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Our aim in this study was to measure serum levels of methylarginines and related metabolites in patients with ankylosing spondylitis (AS), moreover, to investigate the relationship between these parameters and various clinical and laboratory parameters of patients with AS. The study included 60 patients with AS and 60 healthy volunteers. Serum asymmetric dimethylarginine (ADMA), L-N monomethylarginine (L-NMMA), symmetric dimethylarginine (SDMA), arginine (Arg), homoarginine (hArg), ornithine, and citrulline concentrations were measured with tandem mass spectrometry. In addition, participants were divided into three groups according to the treatment regimen: TNF-α inhibitor group (n = 25), conventional therapy group (n = 35), and control group (n = 60). These groups were compared in terms of serum levels of methylarginine pathway metabolites and various biochemical parameters. It was found that total methylated arginine load significantly increased in patients with AS (p < 0.001), and the Arg/ADMA ratio was positively correlated with HDL levels and negatively correlated with glucose, ESR, total cholesterol, triglyceride, and LDL levels. In addition, serum ADMA, SDMA, total methylated arginine load, and CRP levels were lower (p < 0.05) in the TNF-α group compared to the conventional treatment group. To the best of our knowledge, this is the first study to comprehensively investigate serum methylarginine levels in patients with AS. Elevated total methylated arginine load and decreased global arginine bioavailability ratio (GABR) indicate that NO metabolism is impaired in patients with AS. Therefore, the increased cardiovascular risk in patients with AS may be related to the decreased NO production or bioavailability due to the elevated total methylarginine load., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Multiple sclerosis (MS) is an autoinflammatory, chronic central nervous system disease. In the pathogenesis of the disease increased nitric oxide (NO) levels play an important role. Nitric oxide (NO) has neuroprotective effects in physiological conditions, however, it is thought that excessive NO formation in MS may lead to demyelination and axonal damage. Derivatives of methylarginine including asymmetric dimethyl arginine (ADMA), L-N monomethyl arginine (L-NMMA), symmetric dimethyl arginine (SDMA) directly or indirectly reduce NO production. Our aim was to measure the levels of methylarginine derivatives and citrulline, ornithine, arginine, homoarginine levels, which are metabolites associated with NO metabolism, in MS subgroups., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Asymmetric dimethylarginine, symmetric dimethylarginine, and L-monomethylarginine are originated from the subsequent proteolytic catalysis of methylated arginine residues on different proteins and inhibit the endogenous nitric oxide generation. The changes in total methylarginine load (Asymmetric dimethylarginine plus symmetric dimethylarginine plus L-monomethylarginine) may contribute to hypertension. The aim of this study was to determine serum methylarginine concentrations in patients with masked hypertension and determine the association between these biomarkers and blood pressure measurements. Control group, masked hypertension and hypertension groups consisted of 40 subjects (11 males, 28 females, mean age 48.6 ± 13.1), 28 subjects (14 males, 14 females, mean age 50.9 ± 11.0) and 36 subjects (15 males, 21 females, mean age 54.4 ± 12.3 years), respectively ( P = 0.149). Serum total methylarginine load was significantly higher in hypertension group (0.63 ± 0.23) compared to masked hypertension (0.49 ± 0.16) and control groups (0.38 ± 0.13) ( P = 0.008 and P < 0.001). While there was no statistically significant difference between healthy control groups [0.147 (0.03-0.29)] and masked hypertension patients [0.144 (0.05-0.42)] for serum symmetric dimethylarginine levels ( P = 0.970), it was markedly elevated in hypertension group [0.25 (0.07-0.54)] compared to masked hypertension group [0.14 (0.05-0.42)] ( P = 0.001). Serum total methylarginine load was positively correlated with night-time SBP (r = 0.214, P = 0.029). Serum methylarginine levels might be a useful marker for determining the courses of clinical hypertension.

Background: Nitric oxide synthase (NOS) is present in the brain and cerebral arteries and it enables the synthesis of nitric oxide (NO), which plays a critical role in brain perfusion. Asymmetrical dimethylarginine (ADMA) is an endogenous NOS inhibitor., Objectives: The aim of this study was to evaluate serum ADMA levels, which are an indicator of endothelial dysfunction of the renal functions in patients with acute ischemic stroke, and to determine whether there is a possible correlation between ADMA and NO levels and the l-arginine-to-ADMA ratio., Material and Methods: Fifty-two patients (22 male and 30 female; mean age: 75.2 ±10.1 years) with a diagnosis of acute ischemic stroke in the first 24 h post-stroke and 48 healthy individuals (controls; 13 male and 35 female; mean age: 60.1 ±7.92 years) were included in this study. The risk factors recorded and evaluated were age and gender of the patients, serum lipid levels, serum ADMA levels, nitrate-to-nitrite ratios, l-arginine, l-arginine-to-ADMA ratios, sedimentation rate, C-reactive protein (CRP), urea and creatinine levels, and glomerular filtration ratio (eGFR)., Results: The mean serum ADMA level was 0.48 ±0.23 μM for the patients and 0.36 ±0.18 μM for the controls. The mean NO level was 2.78 ±0.59 μM for the patient group and 4.49 ±2.84 μM for the controls. The ADMA levels for the patient group were significantly higher than for the control group (p = 0.011); the NO levels for the patients were significantly lower than for the controls (p < 0.001). The logistic regression method demonstrated that ADMA and NO levels may be independent risk factors for the patient group, and the receiver operating characteristic (ROC) curve analysis showed that both of these variables were discriminative risk factors., Conclusions: An increased serum level of the NOS inhibitor ADMA was found to be a possible independent risk factor for ischemic stroke.

Background: Acne vulgaris is a common skin disease in adolescents known to be associated with oxidative stress. However, the number of studies in which oxidative stress and antioxidants are evaluated together is limited. Aims: In this study, we aimed to investigate L‐arginine/nitric oxide (NO) pathway metabolites, ischemia‐modified albumin (IMA), and vitamin A and E levels in patients with acne and its association with disease severity. Patients/Methods: Ninety patients with acne and 30 healthy adults were included in the study. The serum levels ofL‐arjinin, L‐arginine metabolites, IMA, and vitamins A and E measured in the patient and control groups. Results: Asymmetric dimethylarginine (ADMA), LNG‐monomethyl‐L‐arginine (L‐NMMA) and symmetric dimethylarginine (SDMA), and IMA levels were significantly higher in the patients with acne than in the control group (P ˂.05). The L‐arginine/ADMA ratio and citrulline and vitamin A levels were significantly lower in patients with acne than those of the controls (P ˂.05). ADMA and IMA plasma levels were increased in parallel with the disease severity (P ˂.05). L‐arginine/ADMA ratio, L‐arginine, citrulline, and vitamin A plasma levels decreased as the disease became severe (P ˂.05). Although L‐arginine and vitamin E levels were lower in the patient group compared to the control group, the difference was not statistically significant (P ˃.05). Conclusion: These results suggest that IMA and L‐arginine‐NO pathway associated with ischemia and oxidative stress may play an important role in the pathogenesis and progression of acne vulgaris. [ABSTRACT FROM AUTHOR]