Altered Arginine/Nitric Oxide Pathway in Children Diagnosed Attention Deficit Hyperactivity Disorder, and the Effect of 10 Weeks Methylphenidate Treatment

Objective: Rheumatoid arthritis (RA) is a chronic inflammatory disease and it is associated with premature atherosclerosis development. RA patients have multiple factors to develop premature atherosclerosis. Enhanced asymmetric dimethylarginine (ADMA) is considered as a risk factor for the development of atherosclerosis by inducing endothelial dysfunction. The aim of this study was to investigate the role of asymmetric dimethylarginine, arginine and citrulline levels in patients with RA and their relation to the disease activity parameters for possible role on the disease activity. Methods: 92 patients with RA and 34 healthy controls were included the study. Patients and control blood samples collected for ADMA, arginine and citrulline levels. ADMA, arginine and citrulline levels were measured by pre-column derivatization fluorescence HPLC method. CRP and ESR levels examined on the same day were taken from the patient records. Results: While ADMA levels significantly increased, arginine levels decreased in the patient group. There was no difference in citrulline levels between both groups. Only citrulline and arginine showed a weak positive correlation. ADMA, arginine, and citrulline levels showed no correlation with either biochemical parameters such as CRP or ESR, or disease activity or disease severity. Conclusion: Our study has shown that an increase in ADMA levels with the decrease in arginine levels suggests an increase in arginine turnover to ADMA. Increased ADMA levels can be used for an increased risk for premature development of atherosclerosis in patients with RA. Since high ADMA levels prevent the NO-dependent vasodilatation, a possible role of ADMA in development of premature atherosclerosis may be independent from inflammation.

Nitric oxide (NO) has a critical role in neuronal function; however, high levels lead to cellular injury. While guanidino-methylated arginines (MA) including asymmetric dimethylarginine (ADMA) and N(G)-methyl-l-arginine (NMA) are potent competitive inhibitors of nitric oxide synthase (NOS) and are released upon protein degradation, it is unknown whether their intracellular concentrations are sufficient to critically regulate neuronal NO production and secondary cellular function or injury. Therefore, we determine the intrinsic neuronal MA concentrations and their effects on neuronal NOS function and excitotoxic injury. Kinetic studies demonstrated that the K(m) for l-arginine is 2.38 microm with a V(max) of 0.229 micromol mg(-1) min(-1), while K(i) values of 0.67 microm and 0.50 microm were determined for ADMA and NMA, respectively. Normal neuronal concentrations of all NOS-inhibiting MA were determined to be approximately 15 microm, while l-arginine concentration is approximately 90 microm. These MA levels result in >50% inhibition of NO generation from neuronal NOS. Down-modulation or up-modulation of these neuronal MA levels, respectively, dramatically enhanced or suppressed NO-mediated excitotoxic injury. Thus, neuronal MA profoundly modulate NOS function and suppress NO mediated injury. Pharmacological modulation of the levels of these intrinsic NOS inhibitors offers a novel approach to modulate neuronal function and injury.

Background: Bronchopulmonary dysplasia (BPD) continues to be an important problem in neonates especially premature infants despite improved facilities of care, monitoring and treatment. Pulmonary hypertension (PH) is a major complicating factor and key cause of mortality in this population. Altered vascular and alveolar growth particularly in canalicular and early saccular stages of lung development following mechanical ventilation and oxygen therapy result in arrest of the lung development leading to BPD with PH. Early recognition of PH in infants with these risk factors is important for optimal management. We tested the hypothesis that asymmetric dimethylarginine, would be greater in infants with bronchopulmonary dysplasia associated pulmonary hypertension than in infants with BPD alone. The Aim: The aim of the current study was to measure the Asymmetric dimethylarginine (ADMA) levels, arginine levels & the plasma arginine-to-ADMA ratio in newborn infants with broncho-pulmonary dysplasia, to evaluate echocardiographic parameters among neonates with bronchopulmonary dysplasia, to correlate between plasma ADMA & arginine-to-ADMA ratio and echocardiographic (ECHO) parameters in those patients and to compare full term & preterm neonates with bronchopulmonary dysplasia as regard to plasma ADMA level. Methods: A case-control study was carried out of ninety (90) newborns selected from those admitted to Neonatal Intensive Care Unit at Maternity & Children Hospital and Alzhraa University hospital during the period from October 2015 to March 2018. Neonates were divided into 2 groups: Patient with BPD with PH (cases group): It included 45 neonates with BPD & PH, 35 preterm neonates and 10 full term neonates. Patient with BPD only (Control group): It included 45 neonates with BPD without PH. These 45 neonates were divided as 22 preterm neonates and 23 full term neonates. Laboratory work was done in Alzhraa University hospital. Asymmetric dimethylarginine (ADMA) levels & arginine levels were measured using competitive enzyme linked immune-assay (ELISA). Results: Patients with both BPD and PH had greater plasma levels of ADMA than patients with BPD alone (P value 0.000). ADMA level > 186 ng/dl can predict development of PH in patient with BPD with sensitivity 100% and specify 100%. Preterm neonates with BPD had greater level of ADMA than full term neonates (P value 0.002). There was no statically significance difference between level of ADMA if withdrawn before or after 28 days of age (range of age at time of sampling in our study was 23 - 40 days) (P value 0.878), even ADMA level increased above the cut point early in the disease before we screened some cases by ECHO. There was no statically significance difference between level of arginine in cases and control groups with P value 0.530. The plasma arginine-to-ADMA ratio was lower in cases than in controls suggesting a greater likelihood of inhibition of nitric oxide production in patients with both BPD and PH than in patients with BPD alone (P value 0.000). ADMA level can predict severity of pulmonary hypertension in patient with BPD, as it was positively correlated with the grade of pulmonary hypertension (P value 0.006). ADMA level is higher in neonates with BPD and PH who died than those who survived; it can predict death in neonates with BPD &PH at cut off point > 643 ng/dl. Conclusion: ADMA increased in newborn infants with BPD, who developed PH. ADMA may have diagnostic and prognostic values. ADMA level was higher in preterm neonates than full term neonates and its level was correlated positively with severity of PH. ADMA levels were significant higher in infants with BPD with PH who died later than those who survived. There was no statically significance difference between levels of ADMA, whether it was drawn before or after 28 days of age (range 23 - 40 days). Echocardiographic screening and ADMA measurement could help in prevention of PH, diagnosis and early treatment of newborn infants suffering from BPD.

FIGURE 1. Changes in cortical thickness provide one measure of brain maturation. A large longitudinal study found that for most areas of cortex, children with attention deficit hyperactivity disorder (ADHD) reach peak cortical thickness several years later than typically developing children, supporting presence of developmental delay. The rate of cortical thinning also differed between the group who continued to meet diagnostic criteria into adulthood (persistent ADHD) and those who did not (remitted ADHD). Areas of cortex in which the rate of thinning correlated with adult symptom level (green, more symptoms associated with more thinning) are approximated on medial and lateral simplified representations of cortex. An earlier study also identified multiple areas in which cortex was thinner in adults with persistent ADHD compared with controls (orange). In addition, this study noted some areas of thicker cortex in remitted ADHD when compared with persistent ADHD (blue).

ADMA and SDMA levels in healthy men exposed to tobacco smoke

Asymmetric dimethylarginine (ADMA) has been found as correlated with endothelial dysfunction and oxidative stress. There are few studies regarding ADMA and nitric oxide (NO) levels in patients with migraine and alterations of ADMA and NO levels during migraine attack are not well-known. Therefore, in present study, we aimed to measure NO and ADMA levels in patients with migraine and compare them with the control group to investigate the correlation between migraine, oxidative stress and endothelial dysfunction. The migraine group consisted of 59 patients, including 22 suffering from migraine with aura and 37 suffering from migraine without aura. The control group consisted of 31 healthy volunteers without headache. The patients in migraine group were divided into subgroups based on whether attack period was present or not and whether it was migraine with or without aura. Plasma ADMA levels were measured using an enzyme-linked immunosorbent assay method. Migraine patients had higher concentrations of NO (35.6 ± 7.7, 31.0 ± 6.2 μmol/L, respectively, p = 0.005) and ADMA (0.409 ± 0.028, 0.381 ± 0.044 μmol/L, respectively, p = 0.001) levels when compared with the healthy controls. During migraine attack, NO and ADMA levels were found to be significantly higher in migraine group as compared to control group (respectively, p = 0.015, p = 0.014). Similarly, NO and ADMA levels in the patients with migraine in the interictal period were found to be significantly higher as compared to control group (p = 0.011, p = 0.003). In conclusion, higher ADMA and NO levels of patients with migraine supported that oxidative stress and endothelial dysfunction may have a role in migraine pathogenesis.

Objectives. We aimed to explore whether the use of methylphenidate relates leptin, ghrelin, adiponectin, and brain-derived neurotrophic factor (BDNF). In addition, the relationship between methylphenidate-related weight loss in attention deficit hyperactivity disorder (ADHD) patients and these biomolecules were evaluated. Methods. Thirty ADHD patients receiving methylphenidate and 20 healthy controls were included. Leptin, ghrelin, adiponectin, and BDNF levels were measured at baseline and after two-month treatment in both groups. Results. At baseline, leptin, ghrelin, adiponectin, and BDNF levels were similar in the ADHD and control groups. The most common adverse events occurring in the ADHD group after a 2-month treatment period included loss of appetite (70%) and weight loss (66.7%). A significant difference was found in body weight, BMI, and CGI scores of the ADHD patients after the treatment. While post-treatment ghrelin and adiponectin levels were significantly higher in the ADHD group, BDNF level was significantly lower. Post-treatment decrease in leptin levels was not significant. Conclusions. Leptin and BDNF were not associated with poor appetite and/or weight loss due to methylphenidate treatment. However, ghrelin and adiponectin might be biomolecules that play a role in underlying neurobiological mechanisms of methylphenidate-related appetite or weight loss.

The effects of asymmetric dimethyl arginine and nitric oxide levels on early prognosis in patients with myocardial infarction

Objective: Nitric oxide (NO) formed by the enzyme NO synthase (NOS) from l-arginine, is an important mediator for pathogen elimination. Being a potent vasodilator NO is implicated in hypotension and decreased organ perfusion in sepsis. Asymmetric dimethylarginine (ADMA) is an endogenous NOS inhibitor. We investigated ADMA and l-arginine levels in neonatal sepsis and their relation to disease severity.Methods: A prospective controlled study was conducted including 31 neonates with sepsis and 20 controls. Serum ADMA and l-arginine levels were measured within 24 h of sepsis diagnosis. Clinical and laboratory data including clinical risk index for babies (CRIB) score, presence of septic shock, organ dysfunction and death were recorded.Results: l-Arginine and ADMA levels were higher in neonates with sepsis compared to controls (p = 0.029 and p = 0.001, respectively). Neonates with septic shock had higher ADMA levels compared to septic neonates without shock (p = 0.026) and controls (p < 0.001). l-Arginine levels were higher in neonates with septic shock compared to septic neonates without shock (p = 0.012) and controls (p < 0.001). Survivors and non-survivors had similar l-arginine and ADMA levels. ADMA levels were correlated with CRIB score (rho = 0.320, p = 0.025).Conclusion: l-arginine and ADMA levels are elevated in neonatal sepsis and even higher levels are observed in septic shock.

10573 Background: Cancer associated thrombotic complications are primarily due to endothelial dysfunction and upregulation of inflammatory processes. Nitric oxide (NO) represents one of the major endothelial derived vasoactive mediators. Asymmetric dimethylarginine (ADMA) is an endogenous competitive inhibitor of NO synthase which inhibits NO production at pathophysiologic levels. Plasma ADMA levels are upregulated in atherosclerosis, hypertension, end stage renal disease, chronic heart failure and microangiopathy. Methods: To test the hypothesis that endothelial dysfunction in cancer patients may result in increased ADMA levels, plasma samples were retrospectively analyzed from an open label, multidose, active comparator designed study in which all patients (n = 110) were initially treated with low molecular weight heparin, enoxaparin (E) at 1–1.5 mg/kg sc for 5 days and further subdivided into group E which continued to receive E and warfarin (W) group which was given oral anticoagulants for a period of up to 12 weeks. Baseline blood samples (BL), 5 days post E (IPE) and 4–6 week samples from the E and W were analyzed for ADMA and NO levels by ELISA methods. Results: Both the ADMA and NO levels were markedly elevated in cancer patients. The E treated group showed a marked decrease in the ADMA levels which persisted throughout the treatment period. However, in the W converted group the ADMA levels rebounded to an increased level indicating that E differentially regulated ADMA in these patients. The down regulation pattern of NO was similar for both E and W. Conclusions: These results suggest that patients with cancer and thrombosis exhibit simultaneous upregulation of ADMA and NO. While E and W show a differential regulation of ADMA both result in downregulation of NO. The fact that E regulates ADMA is highly suggestive of its role in iNOS regulation which may be involved in the inflammatory response in cancer patients. [Table: see text] No significant financial relationships to disclose.

Aim. Attention Deficit Hyperactivity Disorder (ADHD) is a major risk factor for the development of substance use disorders (SUD). Patients with both ADHD and SUD become addicted at a younger age, use more substances and are hospitalized more often than SUD patients without ADHD. However, in clinical practice ADHD patients with SUD are not diagnosed sufficiently, especially in adulthood. This study aims to evaluate characteristics of ADHD patients with SUD. Method. This is a retrospective, non-randomized study. All the files of the patients who had applied for treatment for substance use disorders were screened. The patients who had been suffering just for alcoholism were excluded. The patients who had illegal substance use were included and divided into two groups. The first group was consisted with the patients who had both ADHD and SUD together. The second group was consisted with the patients who had only SUD. All the files of the patients were screened for onset of SUD, substance preferences, comorbid psychiatric disorders and history of family SUD . Results. Of the 72 patients were affected by SUD (57 males and 15 females), 55 of them were met the ADHD criteria according to DSM-IV. No statistical significant differences were observed between ADHD and non-ADHD subjects as far as mean age, gender, education level were concerned. The two groups did not show any significant differences in primary substance choice. Cannabis was the most commonly used substance for abuse and dependence. We divided drugs into different categories such as cannabis, heroin, hallucinogen, amphetamine, volatile, nicotine, alcohol, cocaine and no statistical significant differences were found between ADHD and non-ADHD groups (all values, p > 0.05). Using ecstasy showed statistically significant difference between ADHD and non-ADHD groups [χ2 (1) = 4.124, p 0.05). Abuse of synthetic cannabinoids were found significantly different between ADHD group and non-ADHD group [χ2 (1) = 5.493, p < 0.05]. ADHD group uses synthetic cannabinoids significantly higher than the non-ADHD group. The age of onset of substance use in ADHD and non-ADHD groups differed significantly [χ2 (1)= 32,998 p < 0.001]. Subjects with ADHD had an earlier onset of SUD compared to the subjects of non- ADHD. Most of the ADHD group starts using illicit drugs before 15 years of age. Discussion. Findings of this study consistent with previous studies reported that ADHD can be considered as an important risk factor for the development of addiction.The results of the present study show that ADHD is not rare among the patients with SUD who are seeking treatment. Moreover, even if the patient suffers just only for SUD he/she should be evaluated for ADHD for an effective treatment.

Background: Nitric oxide (NO), synthesized from the amino acid L-arginine by the action of NO synthases (NOS), is a pulmonary vasodilator. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NOS. Preterm infants have higher plasma ADMA concentrations than term infants which could cause inhibition of NO synthesis and deterioration in pulmonary functions. We aimed to investigate the relationship between serum ADMA and L-arginine levels of preterm infants and respiratory distress syndrome (RDS), requirement of surfactant treatment, duration of mechanical ventilation, oxygen treatment, and development of bronchopulmonary dysplasia (BPD).Methods: A prospective cohort study was conducted including 80 preterm infants born with gestational age (GA) ≤ 32 weeks and birth weight (BW) ≤ 1500 g. Blood samples were obtained from all infants immediately after birth, and at postnatal 28th day of age. The relationship of first-day serum ADMA and L-arginine levels and surfactant requirement, duration of mechanical ventilation, oxygen treatment was investigated. Serum ADMA and L-arginine levels at 1st and 28th days were compared at patients with and without BPD. The role of serum ADMA levels at postnatal 28th day of age to predict the requirement of oxygen at postmenstrual 36 weeks of age was also investigated.Results: Eighty preterm infants (42 male, 38 female) were enrolled in the study. Mean BW and GA for the total cohort was 1144.81 ± 220.44 g and 28.3 ± 1.8 weeks, respectively. Sixty-one infants were diagnosed as RDS and 44 infants treated with surfactant. The first-day ADMA levels were significantly higher in infants with surfactant requirement (1.14 ± 0.23 versus 0.86 ± 0.37, p < 0.01). First-day L-arginine levels were lower in infants with surfactant requirement compared to infants without surfactant requirement (22.32 ± 2.33 versus 23.75 ± 2.42, p > 0.05) but not significantly. Serum ADMA and L-arginine concentrations at first day were not different among infants with and without BPD (p > 0.05). ADMA concentrations at 28th day was significantly higher in infants with BPD (1.00 ± 0.25 versus 0.81 ± 0.25, p < 0.05). The cutoff level of 0.875 μmol/L for ADMA at 28th day offered the best predictive value for oxygen requirement at postnatal 36 weeks of age with a sensitivity of 88% and a specificity of 54%.Conclusıon: Serum ADMA and L-arginine levels are related to pulmonary morbidities in newborn. The results of this study show that increased ADMA levels are associated with poor pulmonary outcomes in preterm infants.

The traditional risk factors of hypercholesterolemia, hypertension, diabetes mellitus, and tobacco exposure identify a subset of patients at greater cardiovascular risk. A variety of clinical phenotypes, biochemical markers, and genetic polymorphisms have been proposed to explain the variance in risk not explained by the traditional factors. Notably, all of the traditional risk factors, as well as the great majority of new risk markers, are associated with endothelial vasodilator dysfunction. Because the end points (endothelial dysfunction leading to plaque formation, progression, and rupture) are the same, it follows that diverse risk factors ultimately share common pathways(s) of pathobiology. We and others have provided evidence for a ubiquitous mechanism of endothelial pathobiology shared by all risk factors and markers examined to date. This mechanism of endothelial derangement is mediated by an endogenous inhibitor of nitric oxide synthase (NOS), a molecule known as asymmetrical dimethylarginine (ADMA). Risk factors impair endothelial vasodilator function by causing the accumulation of ADMA. Furthermore, by blocking NO generation, ADMA initiates and promotes processes involved in atherogenesis, plaque progression. and plaque rupture. This review examines the burgeoning body of literature that supports ADMA as an “Uber marker,” a biochemical factor mediating the adverse vascular effects of many other risk factors and markers. Endothelial NOS converts the amino acid l-arginine into l-citrulline and NO. The importance of NO in vascular homeostasis has been discussed elsewhere.1 In addition to its vasodilator activity, NO inhibits key processes involved in vascular disease, including leukocyte adhesion, platelet aggregation, and vascular smooth muscle cell proliferation. In animal models, alterations in vascular NO synthesis profoundly influence the progression of atherosclerosis and restenosis.2–6 These experimental observations have gained greater significance with recent reports that impairment of the NOS pathway independently predicts cardiovascular events.7–11 Major causes of impairment of the NOS pathway are …

Asymmetric dimethylorginine levels and carotid intima-media thickness in obese patients with polycystic ovary syndrome

In this issue of the Journal, Grasemann and coworkers (pp. 1363–1368) report that levels of asymmetric dimethyl arginine (ADMA) are increased in cystic fibrosis (CF) airways (1). ADMA inhibits cellular arginine uptake and nitric oxide (NO) synthase (NOS) activity. Levels of ADMA decrease during antibiotic therapy in association with improved lung function. This observation may prove to have therapeutic relevance. However, it is important to note that increased ADMA in CF airways may be both beneficial (through inhibition of NO production) and harmful (through inhibition of S-nitrosothiol production). Nitric oxide in the concentrations measured in exhaled air (parts per billion) is generally irrelevant to normal lung physiology (2). However, NO can be relevant to lung pathology. It interacts with oxygen, superoxide, and other molecules to injure airway epithelium. Products of these reactions, such as nitrous acid and peroxynitrous acid, are potent cytotoxins downstream of inducible NOS activity (3). Nitric oxide can also affect bacteria in the CF airway (4, 5). Indeed, the CF airway is a complex ecosystem in which nitrogen oxides, oxygen, protons, and more complex chemical species are exchanged between prokaryotic and eukaryotic cells (Figure 1; 4–7). For example, levels of NO are lower than normal in the CF airway, in part because NO is consumed by Pseudomonas, Aspergillus, and other denitrifying organisms (4). NO can serve both as an electron acceptor (dissimilatory denitrification, ultimately forming ammonia) and as a precursor for amino acid formation (assimilatory denitrification). Airway NO levels rise and NH3 levels fall with antibiotic therapy in CF (4). Levels of oxidized NO in the form of nitrate are high in the CF airway (6); and nitrate, like NO, can feed denitrifying organisms. Together, the effects of NOS products to cause cytotoxicity and promote prokaryotic growth suggest that the high levels of ADMA should be advantageous for patients with CF, and that a decrease in ADMA levels with antibiotic therapy might be disadvantageous. Figure 1. Cystic fibrosis airway nitrogen redox ecology. Nitric oxide (NO) synthase (NOS) isoforms in the cystic fibrosis (CF) lung produce both NO and S-nitrosothiols. NO is oxidized to nitrite (NO2−) and nitrate (NO3−). In this issue of the Journal ... However, NOS also produces S-nitrosothiols in concentrations two log orders higher than NO (8–10). S-nitrosothiols are antimicrobial. They augment ciliary beat frequency (2). They relax human airway smooth muscle and prevent tachyphylaxis to β2-adrenergic agonists (2, 10, 11). They inhibit amiloride-sensitive sodium transport (12). They augment expression, maturation and function of delF508 CF transmembrane conductance regulator through inhibition of the expression of Hsp70/Hsp90-organizing protein (13). S-nitrosothiol levels are decreased in the CF airway (14), consistent with high ADMA levels (1); indeed, S-nitrosothiol replacement therapy improves oxygenation in CF (9). Prevention of S-nitrosothiol formation is therefore likely to be an important disadvantage of having high levels of ADMA in the CF airway (1). We do not know why ADMA levels are high in CF. One possible mechanism is based on what we know about the CF airway ecosystem. Anti-pseudomonal therapy decreases ADMA levels in patients with CF (1). Biochemically, ADMA levels are decreased by dimethylarginine dimethylaminohydrolases (DDAHs). DDAHs are inhibited by S-nitrosylation, or physiological protein modification by NO (15). S-nitrosylation is driven both by NOS activation and—in relatively acidic conditions in the CF airway ecosystem (5)—by nitrite protonation; at baseline, this should increase ADMA levels. Antimicrobial therapy can decrease bacterial conversion of abundant airway nitrate to nitrite. Nitrite depletion would decrease DDAH S-nitrosylation, thereby increasing ADMA breakdown during the course of therapy. However, this proposed mechanism is speculative. Much work remains to be done. The CF airway is dark, damp, and largely anaerobic (7). It is also surprisingly well-suited to denitrifying prokaryotic species, given that NOS expression is decreased and ADMA levels are increased. To understand why—and to learn how to use nitrogen oxide redox ecology to therapeutic advantage—we need to get beyond simply modeling NO radical diffusion (2, 3). The Cystic Fibrosis Foundation has shown the benefit of promoting interactions among scientists across disciplines. The work of Grasemann and coworkers suggests that there might be much to gain by organizing a small working group to bring together nitrogen balance ecologists, biochemists, CF airway epithelial biologists, and mathematicians experienced in biochemical modeling. This group could model prokaryotic and eukaryotic outcomes of specific CF interventions to identify strategies to optimize therapeutic development in CF. The elegant insights of Grasemann and coworkers serve to alert us that both the benefits and toxicities of airway nitrogen oxides need to be better understood to improve clinical outcomes in CF.