Relationship of tryptophan metabolites with the type and severity of multiple sclerosis.

BACKGROUND: Tryptophan is an essential amino acid primarily metabolized by the kynurenine pathway in mammals. Intermediate metabolites emerging in this pathway have been associated with many neurogenerative diseases. This study aimed to compare tryptophan pathway metabolite levels in patients with multiple sclerosis (MS) and healthy controls and reveal the relationship of tryptophan metabolites with disease subtype and the Expanded Disability Status Scale (EDSS) score. METHODS: The study included a total of 80 MS cases [53 with relapsing remitting MS (RRMS) and 27 with secondary progressive MS (SPMS)] and 41 healthy volunteers. The patients with RRMS were further divided into relapse (RRMS-attack) and non-attack (RRMS-stable) groups. Using liquid chromatography mass spectrometry, tryptophan, kynurenine, kynurenic acid, quinolinic acid, 3-hydroxykynurenine, and 3-hydroxyanthranilic acid levels were measured. The serum metabolite levels of the patient and control groups were compared. In addition, the link and relationship between the EDSS score and disease duration of the patients and their plasma tryptophan metabolite levels were examined. RESULTS: The tryptophan level of the patient group was significantly lower than that of the healthy controls (p<0.05). The kynurenine (105.38±65.43), quinolinic acid (10.42±3.56), kynurenine/tryptophan ratio (0.0218±0.019), and quinolinic acid/kynurenic acid ratio (1.7054±0.96141) of the patients with MS were significantly higher compared to the controls (p<0.05). In the receiver operating characteristic analysis of the power of kynurenine/tryptophan and quinolinic acid/kynurenic acid ratios in predicting the disease, both ratios predicted the diagnosis of MS (area under the curve: 0.793 and 0.645, respectively; p<0.05), albeit at low sensitivity and specificity. The parameters were similar between the RRMS-attack and RRMS-stable patient groups (p>0.05). There was also no significant difference between the RRMS and SPMS patient groups in terms of tryptophan metabolites (p>0.05). Lastly, no significant relationship was observed between tryptophan metabolites and MS subtype and the EDSS score. CONCLUSION: Our findings revealed that the kynurenine pathway involved in the tryptophan metabolism differed between the patients with MS and healthy controls, and this difference may be a limited guide in the diagnosis of MS, due to major overlaps in values for MS versus Controls, and is insufficient to determine the disease subtype.

Kynurenine pathway of tryptophan metabolism in patients with familial Mediterranean fever.

BACKGROUND: Familial Mediterranean fever (FMF) is an autoinflammatory syndrome characterized by recurrent episodes of fever and aseptic polyserositis. Subclinical inflammation generates a hidden threat to the development of FMF complications such as amyloidosis in attack-free intervals. The kynurenine pathway (KP) has been considered an important player in inflammation and immune response. The study was aimed to measure serum levels of KP metabolites in patients with FMF in the attack-free period. METHODS: A total of 161 participants were recruited from the rheumatology department in this single-centre, case-control study. Participants meeting the eligibility criteria were divided into healthy controls (n = 80) and FMF (n = 81). The laboratory data were obtained from the electronic registration database. Serum tryptophan (TRP), kynurenine (KYN), kynurenic acid (KYNA), 3-hydroxyanthranilic acid, 3-hydroxykynurenine (3HK), and quinolinic acid (QUIN) concentrations were measured with tandem mass spectrometry. Laboratory findings of FMF patients and healthy controls subjects were compared and evaluated. RESULTS: Serum TRP and KYNA levels were significantly decreased in both FMF groups compared to the control group, while the levels of KYN, QUIN, 3HK, the KYN/TRP ratio, and red cell distribution width were higher. CONCLUSION: TRP degradation by the KP is increased in patients with FMF. KP metabolites can be useful in demonstrating subclinical inflammation.

Assessment of serum neopterin and calprotectin as biomarkers for subclinical inflammation in patients with familial Mediterranean fever.

BACKGROUND: Familial Mediterranean fever (FMF) is the most common autoinflammatory disease characterized by short, repeated, and self-limiting attacks of fever and serositis. Subclinical inflammation can persist in the periods with no symptoms and result in amyloidosis even with colchicine treatment. Neopterin and calprotectin have been considered essential players in inflammation and immune response. AIM: The study was aimed to measure serum levels of neopterin and calprotectin in patients with FMF in the attack-free period. METHODS: A total of 160 participants were recruited from the rheumatology department in this single-center, case-control study. Individuals having the inclusion criteria were divided into healthy controls (n = 80) and FMF (n = 80). The laboratory data were acquired from the electronic registration database. Serum calprotectin and neopterin were measured with ELISA test kits. FMF patients and healthy controls' laboratory findings were compared. RESULTS: FMF patients' serum red cell distribution width (RDW), calprotectin, and neopterin values were significantly higher compared to healthy controls. There were no statistically significant differences between calprotectin and neopterin regarding gender, family history, and colchicine response of the FMF patients. CONCLUSIONS: Calprotectin, neopterin, and RDW can be valuable marker candidates to be used in the follow-up of subclinical inflammation in FMF patients.

Raised total methylated arginine load in patients with gout.

Aim: The aim of this study was to measure serum levels of methylarginine derivatives and related metabolites in patients with gout. Materials & methods: This study enrolled 100 patients with gout and 80 patients in the control group. Serum asymmetric dimethylarginine, symmetric dimethylarginine, L-N-monomethylarginine, arginine, homoarginine, citrulline and ornithine levels were measured with tandem mass spectrometry. Results: Serum ornithine, citrulline and total methylated arginine load levels were statistically significantly higher in patients with gout compared with the control group, while serum arginine and homoarginine levels and global arginine bioavailability ratio were statistically significantly lower. Conclusion: There may be an association between gout, methylarginine levels and hyperuricemia and increased risk of cardiovascular disease.

Oxidative Stress-Related miRNAs in Patients with Severe Acne Vulgaris.

Background: Acne vulgaris is a common chronic inflammatory skin disease in adolescents and oxidative stress plays an important role in acne pathology. However, the pathology of acne has not yet been fully elucidated. miRNAs are small noncoding RNAs, and there is increasing evidence for their role in the pathogenesis of skin diseases such as psoriasis, atopic dermatitis, and other inflammatory diseases. Aims and Objectives: The aim of the study was to investigate serum malondialdehyde (MDA) and glutathione (GSH) levels with plasma miRNA expression profile related with oxidative stress in patients with severe acne vulgaris. Materials and Methods: Fifty seven female patients with severe acne and 40 healthy women were included in the study. Plasma miRNA-31, miRNA-200a, and miRNA-21 levels were evaluated by using real-time quantitative polymerase chain rection analysis. MDA and GSH levels were measured as per the manufacturer's procedures using commercial ELISA kits. Results: Plasma miRNA-21 levels were statistically significantly higher in patients with severe acne compared to the control group (P =0.003). Plasma miRNA-200a (P =0.303) and miRNA-31 (P =.652) levels were slightly higher in patients with severe acne compared to the control group, but this difference was not statistically significant. Serum MDA levels (P =.047) were higher in patients with severe acne compared to control group, while serum GSH levels (P =.001) were lower. Conclusion: These results show that oxidative damage is involved in acne etiopathogenesis and especially miRNA-21 may have an important role in the pathogenesis of acne vulgaris.

Determination of serum methylarginine levels by tandem mass spectrometric method in patients with ankylosing spondylitis.

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.

Altered methylarginine levels after surgery in subjects with multinodular goiter.

OBJECTIVES: Thyroid disorders are important risk factor for cardiovascular diseases. Levels of methylarginines such as asymmetric dimethyl arginine (ADMA), L-monomethyl arginine (L-NMMA), symmetric dimethyl arginine (SDMA) are increase in cardiovascular diseases. Multinodular goiter (MNG) is the most common type of goiter in adults. To date, no study has been conducted to determine the levels of methylarginine in euthyroid MNG patients. Our aim in this study is to compare levels of methylarginines and related metabolites in the preoperative, postoperative MNG patients and controls. METHODS: Serum ADMA, SDMA, L-NMMA, homoarginine (hArg), arginine and citrulline concentrations were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS: ADMA (p<0.001), L-NMMA (p=0.002), l-arginine (p=0.006) and citrulline (p<0.001) levels were statistically significantly higher in preop group than postop group. ADMA (p=0.003), L-NMMA (p=0.003) levels were statistically significantly higher and SDMA/ADMA (p<0.001), hArg/ADMA (p<0.001) levels were statistically significantly lower in preop group than control group. CONCLUSIONS: The levels of methylarginines and related metabolites altered in the euthyroid MNG patients compared to the control group, and more importantly, there were significant differences between the preop and postop groups. Therefore, these metabolites can be useful in the diagnosis and prognosis of thyroid disorders, even if thyroid hormone levels are normal.

Serum ADMA levels were positively correlated with EDSS scores in patients with multiple sclerosis.

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.

The relationship between serum clozapine concentrations and hematological parameters by a validated mass spectrometric method.

OBJECTIVE: Clozapine is one of the most effective drugs for resistant schizophrenia, but its severe metabolic and hematological side effects limit the use of clozapine. It has been reported that clozapine blood concentrations should be maintained between 350-600 ng/mL. Our aim was to develop a determination method for clozapine and its main metabolites norclozapine and clozapine-N-oxide, to perform validation studies and to investigate the change of various biochemical parameters in patients using clozapine. METHODS: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for clozapine measurement. Thus, blood samples were collected from 38 patients with schizophrenia and 32 healthy volunteers. Biochemical and hematological parameters were measured by Beckman-Coulter AU 5800 (Beckman Coulter, Brea, USA) and Beckman Coulter LH 780 analyzer (Beckman Coulter, Miami, FL, USA), respectively. Hormone levels were analyzed using Cobas 6000 analyzer (Roche Diagnostics, Germany). RESULTS: The LCMS/MS method was linear between 1.22-2500 ng/mL (r2 = 0.9971) for clozapine. The retention times of clozapine, norclozapine and clozapine-N-oxide were 0.92, 0.89 and 0.95, respectively. Blood glucose (GLU) (p = 0.025), low density lipoprotein (LDL-cholesterol) (p = 0.015), triglyseride (TG) (p = 0.042) and total cholesterol (TC) (p = 0.024) levels were higher; hemoglobin (HGB) (0.015), mean corpuscular hemoglobin (MCH) (0.036), red blood cell count (RBC) (0.020), neutrophil (NEU) (0.034), and platelet (PLT) (P = 0.005) levels were lower in the clozapine group. CONCLUSIONS: This LC-MS/MS method was rapid, simple, cost-effective and suitable for the routine clozapine monitoring. Furthermore, norclozapine and clozapine-N-oxide were also determined. Monitoring of metabolic and hematological parameters with clozapine levels is very important. However, the limitations of the study were that the method was not validated for norclozapine and clozapine-N-oxide, so the validation parameters were not evaluated for these two metabolites.

Determination of serum imatinib and its' metabolite in patients chronic myeloid leukemia.

INTRODUCTION: Imatinib has favorable pharmacokinetic properties, but primary and secondary resistance mechanisms may cause a decrease in clinical response over time. There is a positive correlation between serum imatinib concentrations and treatment response. Our aim was to develop a method for the measurement of imatinib and its' active metabolite N-desmethyl imatinib. METHODS: Serum imatinib and N-desmethyl imatinib levels were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and validation studies were carried out according to CLSI (The Clinical & Laboratory Standards Institute) protocols. Serum samples were collected from 40 patients with chronic myeloid leukemia (CML) and analyzed with LC-MS/MS and ultra high-performance liquid chromatography (UHPLC) methods. RESULTS: The linearity range and correlation coefficient were 12.2-12,500 ng/mL and 0.9987 for LC-MS/MS method, respectively. Limit of quantitation was determined as 24.4 ng/mL. The retention times of imatinib and N-desmethyl imatinib were 1.66 and 1.60 min, respectively. There was no statistically significant difference between the results of both methods. DISCUSSION: This LC-MS/MS method is cost-effective and has adavantages such as using low serum volumes, requiring simple pretreatment steps (only protein precipitation) and reduced turnaround times for analysis.