ORCID Profile
0000-0002-9449-2602
Current Organisation
Flinders University
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Publisher: MDPI AG
Date: 02-02-2022
DOI: 10.3390/MOLECULES27031017
Abstract: The pharmacokinetic profile of ZST316 and ZST152, arginine analogues with inhibitory activity towards human dimethylarginine dimethylaminohydrolase-1 (DDAH1), was investigated in mice using a newly developed HPLC-MS/MS method. The method proved to be reproducible, precise, and accurate for the measurement of the compounds in plasma and urine. Four-week-old female FVB mice received a single dose of ZST316 and ZST152 by intravenous bolus (30 mg/Kg) and oral gavage (60 mg/Kg). ZST316 Cmax was 67.4 µg/mL (intravenous) and 1.02 µg/mL (oral), with a half-life of 6 h and bioavailability of 4.7%. ZST152 Cmax was 24.9 µg/mL (intravenous) and 1.65 µg/mL (oral), with a half-life of 1.2 h and bioavailability of 33.3%. Urinary excretion of ZST152 and ZST316 was 12.5%–22.2% and 2.3%–7.5%, respectively. At least eight urinary metabolites were identified. After chronic intraperitoneal treatment with the more potent DDAH1 inhibitor, ZST316 (30 mg/Kg/day for three weeks), the bioavailability was 59% and no accumulation was observed. Treatment was well tolerated with no changes in body weight vs. untreated animals and no clinical signs of toxicity or distress. The results of this study show that ZST316 has a favorable pharmacokinetic profile, following intraperitoneal administration, to investigate the effects of DDAH1 inhibition in mice.
Publisher: SAGE Publications
Date: 08-2017
Abstract: Methotrexate (MTX) treatment in rheumatoid arthritis (RA) has been associated with lower cardiovascular risk compared to other disease-modifying antirheumatic drugs (DMARDs). We sought to identify whether the MTX-associated cardioprotection involves changes in blood pressure (BP) and/or arterial function. Clinic and 24-hour peripheral and central systolic and diastolic BP (SBP and DBP), augmentation index (AIx), pulse wave velocity (PWV) and plasma asymmetric dimethylarginine (ADMA) were assessed in RA patients on stable treatment with either MTX ± other DMARDs (MTX group, n = 56, age 61 ± 13 years, 70% females) or other DMARDs (non-MTX group, n = 30, age 63 ± 12 years, 76% females). Measurements were performed at baseline and after 8 months. After adjusting for visit, age, gender, body mass index, folic acid use and 28-joint disease activity score, the MTX group had significantly lower clinic peripheral SBP (−7.7 mmHg, 95% CI −13.2 to −2.3, p = 0.006) and DBP (−6.1 mmHg, 95% CI −9.8 to −2.4, p = 0.001) and clinic central SBP (−7.8 mmHg, 95% CI −13.1 to −2.6, p = 0.003) and DBP (−5.4 mmHg, 95% CI −9.1 to −1.6, p = 0.005) versus the non-MTX group. Furthermore, the MTX group had significantly lower 24-hour peripheral and central SBP and DBP and PWV versus the non-MTX group ( p 0.01 for all comparisons). By contrast, there were no significant between-group differences in AIx and ADMA. RA patients on MTX treatment had significantly lower clinic and 24-hour peripheral and central BP compared to those who did not take MTX. The lower BP with MTX may be related to differences in PWV, but not in AIx or ADMA concentrations. Further longitudinal studies including randomized controlled trials are warranted to confirm these findings, to identify other possible mechanisms responsible for the effects of MTX on BP and PWV, and to establish whether these effects might account for the reduced cardiovascular risk with MTX.
Publisher: Bentham Science Publishers Ltd.
Date: 05-2021
DOI: 10.2174/1381612827666210106144247
Abstract: Patients with rheumatoid arthritis (RA), a chronic and disabling autoimmune condition that is characterized by articular and extra-articular manifestations and a pro-inflammatory and pro-oxidant state, suffer from premature atherosclerosis and excessive cardiovascular disease burden. A key step in the pathogenesis of atherosclerosis is impaired synthesis of the endogenous messenger nitric oxide (NO) by endothelial cells which, in turn, alters local homeostatic mechanisms and favors vascular damage and plaque deposition. While the exact mechanisms of endothelial dysfunction in RA remain to be established, there is good evidence that RA patients have relatively high circulating concentrations of the methylated arginine asymmetric dimethylarginine (ADMA), a potent endogenous inhibitor of endothelial NO synthase (eNOS). This review discusses the biological and pathophysiological role of ADMA, the interplay between ADMA, inflammation and oxidative stress, and the available evidence on the adverse impact of ADMA on endothelial function and atherosclerosis and potential ADMA-lowering therapies in RA patients.
Publisher: Georg Thieme Verlag KG
Date: 25-06-2015
Publisher: Georg Thieme Verlag KG
Date: 29-12-2011
Publisher: Springer Science and Business Media LLC
Date: 02-09-2017
DOI: 10.1007/S12603-017-0964-6
Abstract: The current study was designed to explore the associations between L-arginine metabolites and muscle mass and function in old age, which are largely unknown. The study used a randomised, double-blind, placebo-controlled design. The study was carried out in a laboratory setting. 50 healthy older adults [median age 70 years (IQR 67-73) 27 males]. Participants undertook an 18-week resistance exercise program, and a nutritional intervention (fish oil vs. placebo). Serum homoarginine, ornithine, citrulline, asymmetric dimethylarginine (ADMA), NG-monomethyl-L-arginine (L-NMMA), and symmetric dimethylarginine (SDMA), maximal voluntary contraction (MVC) and isokinetic torque of the knee extensors at 30° s-1 (MIT), muscle cross sectional area (MCSA) and quality (MQ) were measured at baseline and after the intervention. No significant exercise-induced changes were observed in metabolite concentrations. There were significant sex differences in the associations between metabolites and muscle parameters. After adjusting for age, glomerular filtration rate and fish oil intervention, citrulline (P=0.002) and ornithine (P=0.022) were negatively associated with MCSA at baseline in males but not females. However, baseline citrulline was negatively correlated with exercise-induced changes in MVC (P=0.043) and MQ (P=0.026) amongst females. Furthermore, amongst males, baseline homoarginine was positively associated with exercise-induced changes in MVC (P=0.026), ADMA was negatively associated with changes in MIT (P=0.026), L-NMMA (p=0.048) and ornithine (P<0.001) were both positively associated with changes in MCSA, and ornithine was negatively associated with changes in MQ (P=0.039). Therefore, barring citrulline, there are significant sex differences in the associations between L-arginine metabolites and muscle mass and function in healthy older adults. These metabolites might enhance sarcopenia risk stratification, and the success of exercise programs, in old age.
Publisher: Bentham Science Publishers Ltd.
Date: 26-12-2019
DOI: 10.2174/1381612825666191112091700
Abstract: Increasing age is a strong, independent risk factor for atherosclerosis and cardiovascular disease. Key abnormalities driving cardiovascular risk in old age include endothelial dysfunction, increased arterial stiffness, blood pressure, and the pro-atherosclerotic effects of chronic, low-grade, inflammation. The identification of novel therapies that comprehensively target these alterations might lead to a major breakthrough in cardiovascular risk management in the older population. Systematic reviews and meta-analyses of observational studies have shown that methotrexate, a first-line synthetic disease-modifying anti-rheumatic drug, significantly reduces cardiovascular morbidity and mortality in patients with rheumatoid arthritis, a human model of systemic inflammation, premature atherosclerosis, and vascular aging. We reviewed in vitro and in vivo studies investigating the effects of methotrexate on endothelial function, arterial stiffness, and blood pressure, and the potential mechanisms of action involved. The available evidence suggests that methotrexate might have beneficial effects on vascular homeostasis and blood pressure control by targeting specific inflammatory pathways, adenosine metabolism, and 5& #039 adenosine monophosphate-activated protein kinase. Such effects might be biologically and clinically relevant not only in patients with rheumatoid arthritis but also in older adults with high cardiovascular risk. Therefore, methotrexate has the potential to be repurposed for cardiovascular risk management in old age because of its putative pharmacological effects on inflammation, vascular homeostasis, and blood pressure. However, further study and confirmation of these effects are essential in order to adequately design intervention studies of methotrexate in the older population.
Publisher: Informa UK Limited
Date: 02-2020
DOI: 10.2147/IJN.S237536
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Sara Tommasi.