Nitric oxide-dependent vasodilation is compromised in isolated pulmonary arteries from COX knockout mice

Cyclooxygenase (COX) has two isoforms and is essential for prostanoid synthesis. COX-1 is constitutive whilst COX-2 is induced in inflammation. Two COX products, prostacyclin (PGI2) and thromboxane (TxA2), regulate vessel tone; PGI2 mediates vasodilation and platelet inhibition, and TxA2 opposes this. PGI2 therapies are used in pulmonary arterial hypertension (PAH). Endogenous TxA2/PGI2 has been linked to PAH in animal models, but the mechanism and isoform involved is debated. We hypothesized that pulmonary artery (PA) from COX-1–/– and COX-2–/– mice would have altered vasodilatory function compared with wild-type (WT; C57Bl6) mice. Vasomotor responses to contractile and relaxant agents were measured by myography. PA from all mice responded similarly to contraction by high potassium or the TxA2 mimetic, U46619. Relaxation to PGI2 receptor or PPARβ/ agonists was also similar in all PAs. However, COX-1–/– and, to a lesser extent, COX-2–/– PA had impaired vasodilation to acetylcholine (ACh), which stimulates endothelial nitric oxide (NO) release, and COX-1–/– PA also dilated less to sodium nitroprusside (SNP); an NO donor that works on smooth muscle (Fig 1). These data indicate an interaction between COX and NO sensing pathways in pulmonary vessels, and have implications for our understanding of PAH.Non peer reviewedFinal Accepted Versio

‘Language shades everything’: Considerations and implications for assessing young children from culturally and linguistically diverse backgrounds

Assessment of young children from culturally and linguistically diverse backgrounds holds the potential to provide important insights into learning. Two researchers investigated an Allied Health screening program that was conducted in three kindergartens in a disadvantaged area of outer Melbourne, Australia. Drawing on narrative inquiry methodology the researchers explored the understandings given to the screening program by Allied Health professionals and Early Childhood teachers and administrators in relation to CALD children. From analysis of interview and focus group data, insights were gained into the way the screening program employed culturally and linguistically responsive practices. Flexible assessment practices, acknowledgement of children’s linguistic abilities and family- centred practice emerged as key strategies to enhance Early Childhood assessment programs that cater to the strengths and needs of young children from CALD backgrounds. However, the investigation demonstrated that issues of equity and compromise are heightened as policy and practice diverge on how to implement these strategies. In conclusion, it is argued, that targeted professional learning could assist Early Childhood teachers to negotiate this divergent space.

Chronic disease outcomes after severe acute malnutrition in Malawian children (ChroSAM): a cohort study

Background Tackling severe acute malnutrition (SAM) is a global health priority. Heightened risk of non-communicable diseases (NCD) in children exposed to SAM at around 2 years of age is plausible in view of previously described consequences of other early nutritional insults. By applying developmental origins of health and disease (DOHaD) theory to this group, we aimed to explore the long-term eff ects of SAM. Methods We followed up 352 Malawian children (median age 9·3 years) who were still alive following SAM inpatient treatment between July 12, 2006, and March 7, 2007, (median age 24 months) and compared them with 217 sibling controls and 184 age-and-sex matched community controls. Our outcomes of interest were anthropometry, body composition, lung function, physical capacity (hand grip, step test, and physical activity), and blood markers of NCD risk. For comparisons of all outcomes, we used multivariable linear regression, adjusted for age, sex, HIV status, and socioeconomic status. We also adjusted for puberty in the body composition regression model. Findings Compared with controls, children who had survived SAM had lower height-for-age Z scores (adjusted diff erence vs community controls 0·4, 95% CI 0·6 to 0·2, p=0·001; adjusted diff erence vs sibling controls 0·2, 0·0 to 0·4, p=0·04), although they showed evidence of catch-up growth. These children also had shorter leg length (adjusted diff erence vs community controls 2·0 cm, 1·0 to 3·0, p<0·0001; adjusted diff erence vs sibling controls 1·4 cm, 0·5 to 2·3, p=0·002), smaller mid-upper arm circumference (adjusted diff erence vs community controls 5·6 mm, 1·9 to 9·4, p=0·001; adjusted diff erence vs sibling controls 5·7 mm, 2·3 to 9·1, p=0·02), calf circumference (adjusted diff erence vs community controls 0·49 cm, 0·1 to 0·9, p=0·01; adjusted diff erence vs sibling controls 0·62 cm, 0·2 to 1·0, p=0·001), and hip circumference (adjusted diff erence vs community controls 1·56 cm, 0·5 to 2·7, p=0·01; adjusted diff erence vs sibling controls 1·83 cm, 0·8 to 2·8, p<0·0001), and less lean mass (adjusted diff erence vs community controls –24·5, –43 to –5·5, p=0·01; adjusted diff erence vs sibling controls –11·5, –29 to –6, p=0·19) than did either sibling or community controls. Survivors of SAM had functional defi cits consisting of weaker hand grip (adjusted diff erence vs community controls –1·7 kg, 95% CI –2·4 to –0·9, p<0·0001; adjusted diff erence vs sibling controls 1·01 kg, 0·3 to 1·7, p=0·005,)) and fewer minutes completed of an exercise test (sibling odds ratio [OR] 1·59, 95% CI 1·0 to 2·5, p=0·04; community OR 1·59, 95% CI 1·0 to 2·5, p=0·05). We did not detect signifi cant diff erences between cases and controls in terms of lung function, lipid profi le, glucose tolerance, glycated haemoglobin A1c, salivary cortisol, sitting height, and head circumference. Interpretation Our results suggest that SAM has long-term adverse eff ects. Survivors show patterns of so-called thrifty growth, which is associated with future cardiovascular and metabolic disease. The evidence of catch-up growth and largely preserved cardiometabolic and pulmonary functions suggest the potential for near-full rehabilitation. Future follow-up should try to establish the eff ects of puberty and later dietary or social transitions on these parameters, as well as explore how best to optimise recovery and quality of life for survivors

Metabolomic profiling of amines in sepsis predicts changes in NOS canonical pathways

Rationale Nitric oxide synthase (NOS) is a biomarker/target in sepsis. NOS activity is driven by amino acids, which cycle to regulate the substrate L-arginine in parallel with cycles which regulate the endogenous inhibitors ADMA and L-NMMA. The relationship between amines and the consequence of plasma changes on iNOS activity in early sepsis is not known. Objective Our objective was to apply a metabolomics approach to determine the influence of sepsis on a full array of amines and what consequence these changes may have on predicted iNOS activity. Methods and measurements 34 amino acids were measured using ultra purification mass spectrometry in the plasma of septic patients (n = 38) taken at the time of diagnosis and 24–72 hours post diagnosis and of healthy volunteers (n = 21). L-arginine and methylarginines were measured using liquid-chromatography mass spectrometry and ELISA. A top down approach was also taken to examine the most changed metabolic pathways by Ingenuity Pathway Analysis. The iNOS supporting capacity of plasma was determined using a mouse macrophage cell-based bioassay. Main results Of all the amines measured 22, including L-arginine and ADMA, displayed significant differences in samples from patients with sepsis. The functional consequence of increased ADMA and decreased L-arginine in context of all cumulative metabolic changes in plasma resulted in reduced iNOS supporting activity associated with sepsis. Conclusions In early sepsis profound changes in amine levels were defined by dominant changes in the iNOS canonical pathway resulting in functionally meaningful changes in the ability of plasma to regulate iNOS activity ex vivo

Pulmonary function deficits in newborn screened infants with cystic fibrosis managed with standard UK care are mild and transient

With the advent of novel designer molecules for cystic fibrosis (CF) treatment, there is huge need for early-life clinical trial outcomes, such as infant lung function (ILF). We investigated the degree and tracking of ILF abnormality during the first 2 years of life in CF newborn screened infants. Forced expiratory volume in 0.5 s (FEV₀.₅), lung clearance index (LCI) and plethysmographic functional residual capacity were measured at ∼3 months, 1 year and 2 years in 62 infants with CF and 34 controls. By 2 years there was no significant difference in FEV₀.₅ z-score between CF and controls, whereas mean LCI z-score was 0.81 (95% CI 0.45–1.17) higher in CF. However, there was no significant association between LCI z-score at 2 years with either 3-month or 1-year results. Despite minimal average group changes in any ILF outcome during the second year of life, marked within-subject changes occurred. No child had abnormal LCI or FEV₀.₅ on all test occasions, precluding the ability to identify “high-risk” infants in early life. In conclusion, changes in lung function are mild and transient during the first 2 years of life in newborn screened infants with CF when managed according to a standardised UK treatment protocol. Their potential role in tracking disease to later childhood will be ascertained by ongoing follow-up

Prenatal Vitamin D Supplementation and Child Respiratory Health: A Randomised Controlled Trial

PMCID: PMC3691177This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Evidence that links loss of cyclooxygenase-2 with increased asymmetric dimethylarginine : novel explanation of cardiovascular side effects associated with anti-inflammatory drugs

© 2014 The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited.BACKGROUND: Cardiovascular side effects associated with cyclooxygenase-2 inhibitor drugs dominate clinical concern. Cyclooxygenase-2 is expressed in the renal medulla where inhibition causes fluid retention and increased blood pressure. However, the mechanisms linking cyclooxygenase-2 inhibition and cardiovascular events are unknown and no biomarkers have been identified.METHODS AND RESULTS: Transcriptome analysis of wild-type and cyclooxygenase-2(-/-) mouse tissues revealed 1 gene altered in the heart and aorta, but >1000 genes altered in the renal medulla, including those regulating the endogenous nitric oxide synthase inhibitors asymmetrical dimethylarginine (ADMA) and monomethyl-l-arginine. Cyclo-oxygenase-2(-/-) mice had increased plasma levels of ADMA and monomethyl-l-arginine and reduced endothelial nitric oxide responses. These genes and methylarginines were not similarly altered in mice lacking prostacyclin receptors. Wild-type mice or human volunteers taking cyclooxygenase-2 inhibitors also showed increased plasma ADMA. Endothelial nitric oxide is cardio-protective, reducing thrombosis and atherosclerosis. Consequently, increased ADMA is associated with cardiovascular disease. Thus, our study identifies ADMA as a biomarker and mechanistic bridge between renal cyclooxygenase-2 inhibition and systemic vascular dysfunction with nonsteroidal anti-inflammatory drug usage.CONCLUSIONS: We identify the endogenous endothelial nitric oxide synthase inhibitor ADMA as a biomarker and mechanistic bridge between renal cyclooxygenase-2 inhibition and systemic vascular dysfunction.Peer reviewedFinal Published versio

Activation and contraction of human ‘vascular’ smooth muscle cells grown from circulating blood progenitors

Blood outgrowth smooth muscle cells offer the means to study vascular cells without the requirement for surgery providing opportunities for drug discovery, tissue engineering and personalised medicine. However, little is known about these cells which has meant their therapeutic potential remains unexplored. Our objective was to investigate for the first time the ability of blood outgrowth smooth muscle cells and vessel derived smooth muscle cells to sense the thromboxane mimetic U46619 by measuring intracellular calcium elevation and contraction. U46619 (10 26 -6 M) increased cytosolic calcium in blood outgrowth smooth muscle cells fibroblasts. Increased calcium signal peaked between 10-20 seconds after U46619 in both smooth muscle cell types. Importantly, U46619 (10-9 to 10-6 M) induced concentration-dependent contractions of both blood outgrowth smooth muscle cells and vascular smooth muscle cells but not in fibroblasts. In summary, we show that functional responses of blood outgrowth smooth muscle cells are in line with vascular smooth muscle cells providing critical evidence of their application in biomedical research

Thrombosis Is Reduced by Inhibition of COX-1, but Unaffected by Inhibition of COX-2, in an Acute Model of Platelet Activation in the Mouse

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Cell-Specific Gene Deletion Reveals the Antithrombotic Function of COX1 and Explains the Vascular COX1/Prostacyclin Paradox.

Rationale: Endothelial cells (ECs) and platelets, which respectively produce antithrombotic prostacyclin and prothrombotic thromboxane A2, both express COX1 (cyclooxygenase1). Consequently, there has been no way to delineate any antithrombotic role for COX1-derived prostacyclin from the prothrombotic effects of platelet COX1. By contrast, an antithrombotic role for COX2, which is absent in platelets, is straightforward to demonstrate. This has resulted in an incomplete understanding of the relative importance of COX1 versus COX2 in prostacyclin production and antithrombotic protection in vivo. Objective: We sought to identify the role, if any, of COX1-derived prostacyclin in antithrombotic protection in vivo and compare this to the established protective role of COX2. Methods and Results: We developed vascular-specific COX1 knockout mice and studied them alongside endothelial-specific COX2 knockout mice. COX1 immunoreactivity and prostacyclin production were primarily associated with the endothelial layer of aortae; freshly isolated aortic ECs released >10-fold more prostacyclin than smooth muscle cells. Moreover, aortic prostacyclin production, the ability of aortic rings to inhibit platelet aggregation and plasma prostacyclin levels were reduced when COX1 was knocked out in ECs but not in smooth muscle cells. When thrombosis was measured in vivo after FeCl3 carotid artery injury, endothelial COX1 deletion accelerated thrombosis to a similar extent as prostacyclin receptor blockade. However, this effect was lost when COX1 was deleted from both ECs and platelets. Deletion of COX2 from ECs also resulted in a prothrombotic phenotype that was independent of local vascular prostacyclin production. Conclusions: These data demonstrate for the first time that, in healthy animals, endothelial COX1 provides an essential antithrombotic tone, which is masked when COX1 activity is lost in both ECs and platelets. These results help us define a new 2-component paradigm wherein thrombotic tone is regulated by both COX1 and COX2 through complementary but mechanistically distinct pathways