Publications
51 results found
Tesfai A, MacCallum N, Kirkby NS, et al., 2017, Metabolomic profiling of amines in sepsis predicts changes in NOS canonical pathways, PLoS ONE, Vol: 12, ISSN: 1932-6203
RationaleNitric 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.ObjectiveOur 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 measurements34 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 resultsOf 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.ConclusionsIn 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.
Huang L-Y, Yen I-C, Tsai W-C, et al., 2017, Rhodiola crenulata Attenuates High Glucose Induced Endothelial Dysfunction in Human Umbilical Vein Endothelial Cells, AMERICAN JOURNAL OF CHINESE MEDICINE, Vol: 45, Pages: 1201-1216, ISSN: 0192-415X
Mohamed NA, Davies RP, Lickiss PD, et al., 2017, Chemical and biological assessment of metal organic frameworks (MOFs) in pulmonary cells and in an acute in vivo model: relevance to pulmonary arterial hypertension therapy, Pulmonary Circulation, Vol: 7, Pages: 1-11, ISSN: 2045-8940
Pulmonary arterial hypertension (PAH) is a progressive and debilitating condition. Despite promoting vasodilation, current drugs have a therapeutic window within which they are limited by systemic side effects. Nanomedicine uses nanoparticles to improve drug delivery and/or reduce side effects. We hypothesize that this approach could be used to deliver PAH drugs avoiding the systemic circulation. Here we report the use of iron metal organic framework (MOF) MIL-89 and PEGylated MIL-89 (MIL-89 PEG) as suitable carriers for PAH drugs. We assessed their effects on viability and inflammatory responses in a wide range of lung cells including endothelial cells grown from blood of donors with/without PAH. Both MOFs conformed to the predicted structures with MIL-89 PEG being more stable at room temperature. At concentrations up to 10 or 30 µg/mL, toxicity was only seen in pulmonary artery smooth muscle cells where both MOFs reduced cell viability and CXCL8 release. In endothelial cells from both control donors and PAH patients, both preparations inhibited the release of CXCL8 and endothelin-1 and in macrophages inhibited inducible nitric oxide synthase activity. Finally, MIL-89 was well-tolerated and accumulated in the rat lungs when given in vivo. Thus, the prototypes MIL-89 and MIL-89 PEG with core capacity suitable to accommodate PAH drugs are relatively non-toxic and may have the added advantage of being anti-inflammatory and reducing the release of endothelin-1. These data are consistent with the idea that these materials may not only be useful as drug carriers in PAH but also offer some therapeutic benefit in their own right.
Ahmetaj-Shala B, Tesfai A, Constantinou C, et al., 2017, Pharmacological assessment of ibuprofen arginate on platelet aggregation and colon cancer cell killing, Biochemical and Biophysical Research Communications, Vol: 484, Pages: 762-766, ISSN: 1090-2104
Nonsteroidal anti-inflammatory drugs (NSAIDs), including ibuprofen, are amongst the most commonly used medications and produce their anti-inflammatory and analgesic benefits by blocking cyclooxygenase (COX)-2. These drugs also have the potential to prevent and treat cancer and some members of the class including ibuprofen can produce anti-platelet effects. Despite their utility, all NSAIDs are associated with increased risk of cardiovascular side effects which our recent work suggests could be mediated by increased levels of the endogenous NO synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA) leading to reduced endothelial NOS activity and associated endothelial cell dysfunction. ADMA is a cardiotoxic hormone and biomarker of cardiovascular risk whose effects can be prevented by l-arginine. The ibuprofen salt, ibuprofen arginate (Spididol®) was created to increase drug solubility but we have previously established that it not only effectively blocks COX-2 but also provides an arginine source able to reverse the effects of ADMA in vitro and in vivo. Here we have gone on to explore whether the formulation of ibuprofen with arginine influences the potency and efficacy of the parent molecule using a range of simple in vitro assays designed to test the effects of NSAIDs on (i) platelet aggregation and (iii) colon cancer cell killing. Our findings demonstrate that ibuprofen arginate retains these key functional effects of NSAIDs with similar or increased potency compared to ibuprofen sodium, further illustrating the potential of ibuprofen arginate as an efficacious drug with the possibility of improved cardiovascular safety.
Duluc L, Ahmetaj-Shala B, Mitchell J, et al., 2017, Tipifarnib prevents development of hypoxia-induced pulmonary hypertension, Cardiovascular Research, Vol: 113, Pages: 276-287, ISSN: 1755-3245
Aims.RhoB plays a key role in the pathogenesis of hypoxia-induced pulmonary hypertension. Farnesylated RhoB promotes growth responses in cancer cells and we investigated whether inhibition of protein farnesylation will have a protective effect. Methods and Results.The analysis of lung tissues from rodent models and pulmonary hypertensive patientsshowed increased levels of protein farnesylation. Oral farnesyltransferase inhibitor tipifarnib prevented development of hypoxia-induced pulmonary hypertension in mice. Tipifarnib reduced hypoxia-induced vascular cell proliferation, increased endothelium-dependent vasodilatation and reduced vasoconstriction of intrapulmonary arteries without affecting cell viability. Protective effects of tipifarnib were associated with inhibition of Ras and RhoB, actin depolymerisation and increased eNOS expression in vitroand in vivo. Farnesylated-only RhoB (F-RhoB) increased proliferative responses in cultured pulmonary vascular cells, mimicking the effects of hypoxia, while both geranylgeranylated-only RhoB (GG-RhoB) and tipifarnib had an inhibitory effect. Label-free proteomics linked F-RhoB with cell survival, activation of cell cycle and mitochondrial biogenesis. Hypoxia increased and tipifarnib reduced the levels of F-RhoB-regulated proteins in the lung, reinforcing the importance of RhoB as a signalling mediator.Unlike simvastatin, tipifarnib did not increase the expression levels of Rho proteins.Conclusions.Our study demonstrates the importance of protein farnesylation in pulmonary vascular remodeling and provides a rationale for selective targeting of this pathway in pulmonary hypertension.
Kirkby NS, Tesfai A, Ahmetaj-Shala B, et al., 2016, Ibuprofen arginate retains eNOS substrate activity and reverses endothelial dysfunction: implications for the COX-2/ADMA axis, The FASEB Journal, Vol: 30, Pages: 4172-4179, ISSN: 0892-6638
: Nonsteroidal antiinflammatory drugs, including ibuprofen, are among the most commonly used medicationsand produce their antiinflammatory effects by blocking cyclooxygenase (COX)-2. Their use is associatedwith increased risk of heart attacks caused by blocking COX-2 in the vasculature and/or kidney, with our recent workimplicating the endogenous NOS inhibitor asymmetric dimethylarginine (ADMA), a cardiotoxic hormone whoseeffects can be prevented by L-arginine. The ibuprofen salt ibuprofen arginate (Spididol) was created to increasesolubility but we suggest that it could also augment the NO pathway through codelivery of arginine. Here weinvestigated the idea that ibuprofen arginate can act to simultaneously inhibit COX-2 and preserve the NO pathway.Ibuprofen arginate functioned similarly to ibuprofen sodium for inhibition of mouse/human COX-2, but onlyibuprofen arginate served as a substrate for NOS. Ibuprofen arginate but not ibuprofen sodium also reversed theinhibitory effects of ADMA and NG-nitro-L-arginine methyl ester on inducible NOS (macrophages) and endothelialNOS in vitro (aorta) and in vivo (blood pressure). These observations show that ibuprofen arginate provides, in onepreparation, a COX-2 inhibitor and NOS substrate that could act to negate the harmful cardiovascular consequencesmediated by blocking renal COX-2 and increased ADMA. While remarkably simple, our findings arepotentially game-changing in the nonsteroidal antiinflammatory drug arena.—Kirkby, N. S., Tesfai, A., AhmetajShala,B., Gashaw, H. H., Sampaio, W., Etelvino, G., Leão, N. M., Santos, R. A., Mitchell, J. A. Ibuprofen arginateretains eNOS substrate activity and reverses endothelial dysfunction: implications for the COX-2/ADMA axis.
Mohamed NA, Ahmetaj-Shala B, Duluc L, et al., 2016, A New NO-Releasing Nanoformulation for the Treatment of Pulmonary Arterial Hypertension., Journal of Cardiovascular Translational Research, Vol: 9, Pages: 162-164, ISSN: 1937-5395
Pulmonary arterial hypertension (PAH) is a chronic and progressive disease which continues to carry an unacceptably high mortality and morbidity. The nitric oxide (NO) pathway has been implicated in the pathophysiology and progression of the disease. Its extremely short half-life and systemic effects have hampered the clinical use of NO in PAH. In an attempt to circumvent these major limitations, we have developed a new NO-nanomedicine formulation. The formulation was based on hydrogel-like polymeric composite NO-releasing nanoparticles (NO-RP). The kinetics of NO release from the NO-RP showed a peak at about 120 min followed by a sustained release for over 8 h. The NO-RP did not affect the viability or inflammation responses of endothelial cells. The NO-RP produced concentration-dependent relaxations of pulmonary arteries in mice with PAH induced by hypoxia. In conclusion, NO-RP drugs could considerably enhance the therapeutic potential of NO therapy for PAH.
Raouf J, Kirkby NS, Ahmetaj-Shala B, et al., 2016, mPGES-1 DELETION INCREASES PROSTACYCLIN AND EVADES THE ELEVATED SYSTEMIC ADMA ASSOCIATED WITH COX-2 INHIBITORS: RELEVANCE TO CARDIOVASCULAR SAFETY OF mPGES-1 INHIBITORS, 36th European Workshop for Rheumatology Research (EWRR), Publisher: BMJ PUBLISHING GROUP, Pages: A11-+, ISSN: 0003-4967
- Author Web Link
- Cite
- Citations: 4
Kirkby NS, Chan MV, Zaiss AK, et al., 2016, Systematic study of constitutive cyclo-oxygenase-2 expression: role of NFκB and NFAT transcriptional pathways, Proceedings of the National Academy of Sciences of the United States of America, Vol: 113, Pages: 434-439, ISSN: 1091-6490
Cyclooxygenase-2 (COX-2) is an inducible enzyme that drives inflammation and is the therapeutic target for widely used nonsteroidal antiinflammatory drugs (NSAIDs). However, COX-2 is also constitutively expressed, in the absence of overt inflammation, with a specific tissue distribution that includes the kidney, gastrointestinal tract, brain, and thymus. Constitutive COX-2 expression is therapeutically important because NSAIDs cause cardiovascular and renal side effects in otherwise healthy individuals. These side effects are now of major concern globally. However, the pathways driving constitutive COX-2 expression remain poorly understood. Here we show that in the kidney and other sites, constitutive COX-2 expression is a sterile response, independent of commensal microorganisms and not associated with activity of the inflammatory transcription factor NF-κB. Instead, COX-2 expression in the kidney but not other regions colocalized with nuclear factor of activated T cells (NFAT) transcription factor activity and was sensitive to inhibition of calcineurin-dependent NFAT activation. However, calcineurin/NFAT regulation did not contribute to constitutive expression elsewhere or to inflammatory COX-2 induction at any site. These data address the mechanisms driving constitutive COX-2 and suggest that by targeting transcription it may be possible to develop antiinflammatory therapies that spare the constitutive expression necessary for normal homeostatic functions, including those important to the cardiovascular-renal system.
Raouf J, Kirkby N, Ahmetaj-Shala B, et al., 2016, mPGES-1 deletion increases prostacyclin and evades the elevated systemic ADMA associatedwith COX-2 inhibitors: relevance to cardiovascular safety of mPGES-1 inhibitors, Publisher: TAYLOR & FRANCIS LTD, Pages: 24-25, ISSN: 0300-9742
Ahmetaj-Shala B, Kirkby NS, Knowles R, et al., 2015, Reply to Letter Regarding Article, “Evidence That Links Loss of Cyclooxygenase-2 With Increased Asymmetric Dimethylarginine: Novel Explanation of Cardiovascular Side Effects Associated With Anti-Inflammatory Drugs”, Circulation, Vol: 132, Pages: E213-E214, ISSN: 0009-7322
Lambden S, Kelly P, Ahmetaj-Shala B, et al., 2015, Dimethylarginine Dimethylaminohydrolase 2 Regulates Nitric Oxide Synthesis and Hemodynamics and Determines Outcome in Polymicrobial Sepsis, ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY, Vol: 35, Pages: 1382-1392, ISSN: 1079-5642
- Author Web Link
- Cite
- Citations: 36
Mitchell JA, Ahmetaj-Shala B, Kirkby NS, et al., 2015, Role of prostacyclin in pulmonary hypertension., Global Cardiology Science and Practice, Vol: 2014, Pages: 382-393, ISSN: 2305-7823
Prostacyclin is a powerful cardioprotective hormone released by the endothelium of all blood vessels. Prostacyclin exists in equilibrium with other vasoactive hormones and a disturbance in the balance of these factors leads to cardiovascular disease including pulmonary arterial hypertension. Since it's discovery in the 1970s concerted efforts have been made to make the best therapeutic utility of prostacyclin, particularly in the treatment of pulmonary arterial hypertension. This has centred on working out the detailed pharmacology of prostacyclin and then synthesising new molecules based on its structure that are more stable or more easily tolerated. In addition, newer molecules have been developed that are not analogues of prostacyclin but that target the receptors that prostacyclin activates. Prostacyclin and related drugs have without doubt revolutionised the treatment and management of pulmonary arterial hypertension but are seriously limited by side effects within the systemic circulation. With the dawn of nanomedicine and targeted drug or stem cell delivery systems it will, in the very near future, be possible to make new formulations of prostacyclin that can evade the systemic circulation allowing for safe delivery to the pulmonary vessels. In this way, the full therapeutic potential of prostacyclin can be realised opening the possibility that pulmonary arterial hypertension will become, if not curable, a chronic manageable disease that is no longer fatal. This review discusses these and other issues relating to prostacyclin and its use in pulmonary arterial hypertension.
Ahmetaj-Shala B, Kirkby NS, Knowles R, et al., 2015, Evidence That Links Loss of Cyclooxygenase-2 With Increased Asymmetric Dimethylarginine, Publisher: Ovid Technologies (Wolters Kluwer Health), Pages: 633-642, ISSN: 0009-7322
<jats:sec> <jats:title>Background—</jats:title> <jats:p>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.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods and Results—</jats:title> <jats:p> Transcriptome analysis of wild-type and cyclooxygenase-2 <jats:sup>−/−</jats:sup> 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- <jats:sc>l</jats:sc> -arginine. Cyclo-oxygenase-2 <jats:sup>−/−</jats:sup> mice had increased plasma levels of ADMA and monomethyl- <jats:sc>l</jats:sc> -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. </jats:p> </jats:sec> <jats:sec&g
Ahmetaj-Shala B, Kirkby NS, Knowles R, et al., 2015, Evidence that links loss of cyclooxygenase-2 with increased asymmetric dimethylarginine novel explanation of cardiovascular side effects associated with anti-inflammatory drugs, Circulation, Vol: 131, Pages: 633-U113, ISSN: 0009-7322
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.
Reed DM, Foldes G, Kirkby NS, et al., 2014, Morphology and vasoactive hormone profiles from endothelial cells derived from stem cells of different sources, Biochemical and Biophysical Research Communications, Vol: 455, Pages: 172-177, ISSN: 1090-2104
Kelly P, Wang Z, Ahmetaj B, et al., 2014, Dimethylarginine dimethylaminohydrolase 2 (DDAH2) regulates nitric oxide production, haemodynamics and vascular responsiveness under basal conditions and outcome in polymicrobial sepsis, NITRIC OXIDE-BIOLOGY AND CHEMISTRY, Vol: 42, Pages: 130-130, ISSN: 1089-8603
Ahmetaj-Shala B, Kirkby NS, Al-yamani M, et al., 2013, Evidence That Links Cyclo-oxygenase-2 Inhibition With Increased Asymmetric Dimethylarginine: Novel Explanation of Cardiovascular Side Effects Associated With Anti-inflammatory Drugs, Scientific Sessions and Resuscitation Science Symposium of the American-Heart-Association, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322
Wang Z, Caplin B, Delahaye M, et al., 2013, The Hemodynamic Effects of Deletion of DDAH2 in Conscious Mice, Scientific Sessions and Resuscitation Science Symposium of the American-Heart-Association, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322
Arrigoni F, Ahmetaj B, Leiper J, 2010, The Biology and Therapeutic Potential of the DDAH/ADMA Pathway, CURRENT PHARMACEUTICAL DESIGN, Vol: 16, Pages: 4089-4102, ISSN: 1381-6128
Arrigoni F, Ahmetaj B, Leiper J, 2010, The Biology and Therapeutic Potential of the DDAH/ADMA Pathway, CURRENT PHARMACEUTICAL DESIGN, Vol: 16, Pages: 4089-4102, ISSN: 1381-6128
- Author Web Link
- Cite
- Citations: 32
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.