Determination of urine catecholamines and metanephrines by reversed-phase liquid chromatography-tandem mass spectrometry

The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma.The goal of this work was to develop a simple liquid chromatography-tandem mass spectrometry(LC-MS/MS)method for determining catecholamines and metanephrines in urine to replace an existing liquid chromatographic method using electrochemical detection.Urine samples were prepared using Oasis weak-cation-exchange cartridges.The eluate was analyzed on an Agilent ZORBAX Eclipse Plus Phenyl-Hexyl column in 3 min.Adrenaline,noradrenaline,dopamine,metanephrine,normetanephrine,and their deuterated internal standards were monitored in positive electrospray ionization mode by multiple reaction monitoring(MRM).No evidence of ion suppression was observed.The assay was linear up to 5μmol/L for adrenaline,5μmol/L for noradrenaline,6.1μmol/L for dopamine,5.6μmol/L for metanephrine,and 34.6μmol/L for normetanephrine,with lower limits of quantification of 5,5,12,6 and 7nmol/L,respectively.The intra-day and inter-day precisions for all analytes ranged from 0.59%to 4.64%and1.98%to 4.80%,respectively.External quality assurance samples were assayed and showed excellent agreement with the target values.This simple method provides an improved assay for determining urine catecholamines and metanephrines.

Capillary electrophoresis with direct chemiluminescence detection for the analysis of catecholamines in human urine

A rapid and sensitive method for the analysis of three catecholamines by capillary electrophoresis （CE） with direct chemiluminescence （CL） detection is described. The detection limits （S/N= 3） were 1.3 × 10^-8 g/mL for isoprenaline, 1.0 × 10^-8g/mL for epinephrine and 2.8 × 10^-8 g/mL for dopamine. The proposed method was successfully applied to the analysis of catecholamines in urine samples of cigarette smokers and nonsmokers. The results showed that there is a close relation between the release of dopamine in human body fluids and cigarette smoking/nonsmoking.

Modified monolithic silica capillary for preconcentration of catecholamines

Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva,the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic silica capillary when it was used to concentrate catecholamines.

CARDIAC RISK STRATIFICATION IN PATIENTS WITH CONGESTIVE HEART FAILURE:A CATECHOLAMINES-β-ADRENOCEPTOR-cAMP PATHWAY

Objective To investigate the stratification risk of catecholamines-β-adrenoceptor (β-AR)-cAMP pathway for cardiogenic death events in patients with congestive heart failure (CHF). Methods A total of 83 identified CHF patients with a baseline and follow-up plasma levels of norepinephrine (NE) and epinephrine (E), lymphocytes β-AR density (Bmax), and intralymphocyte cAMP content in peripheral blood were followed up. Major cardiogenic death events were registered. Results The period between the initial entry and the last follow-up measurement were 51±16 months, the total duration of clinical follow-up after the last measurement were 14±8 months. During follow-up, 39 patients died of cardiogenic (sudden death 17 patients, worsening heart failure 22 patients). Persistence of high NE, E, and cAMP from baseline to follow-up were confirmed as risk predicting factors of cardiovascular events. Persistence NE above 4.0 nmol/L, E above 3.5 nmol/L, and the intralymphocyte cAMP content above 3.5 pmd·mg-1·pro-1 from baseline to follow-up were significant adverse prognostic predictors. The major cardiogenic death events rates per 100 patients-years were 1.33 and 4.82 in patients with NE below and above 4.0 nmol/L (HR: 2.91; 95% CI: 1.08-7.33; P = 0.015); were 1.42 and 4.36 in the patients with E levels below and above 3.5 nmol/L (HR: 2.64; 95% CI: 1.02-6.41; P = 0.019); were 1.81 and 4.67 in the patients with the intralymphocyte cAMP content below and above 3.5 pmd·mg-1·pro-1 (HR: 2.79; 95% CI: 1.04-6.83; P = 0.017), but difference was not significant between the β-AR density below and above median. Conclusions Persistent increase in circulating catecholamines and intralymphocyte cAMP content may increase the long-term mortality in CHF patients.

Factors Affecting Catecholamines in Caregivers of Patients with De­mentia

Background:Caregivers of dementia patients have significantly higher levels of serum IL-6 and CRP compared to non-caregivers,and the ac­cumulation of everyday stressors reportedly promotes the induction of inflammatory markers.However,few studies have identified factors that affect catecholamine levels in caregivers who experience a combination of physical and mental stress from caregiving.Purpose:This study aimed to identify physical factors that impact catecholamine levels in caregivers of dementia patients.Methods:Participants were elderly caregivers living together with elderly Alzhei­mer’s-type dementia patients.We performed logistic regression analysis,with levels of adrenaline,noradrenaline,and dopamine(indicators of catecholamine)as dependent variables.Results:Caregiver BMI had a significant impact on adrenaline levels(OR:0.792;95%CI:0.654-0.960)and noradrenaline levels(OR:1.210;95%CI:1.009-1.451),whereas age had a significant impact on dopamine levels(OR:1.162;95%CI:1.019-1.324).Discussion:While caregiver BMI significantly impacted adrenaline and noradrenaline levels,the mechanism underlying these relationships is unclear.One possibility is that obesity(BMI)and a rise in sympathetic nerve activity contributed to hypertension.Our findings suggest that chronic stress in elderly caregivers may potentially impair the dopaminergic activation system in the brain.Conclusion:There is a need to identify factors which increase BMI in caregivers.Future studies aimed at gaining a better understanding of the lifestyle habits of caregiv­ers and intervention studies aimed at reducing their BMI are warranted.

Flow-injection Chemiluminescence Determination of Catecholamines

A flow injection chemiluminescence (CL) method for the determination of catecholamines is described which is based on their inhibition of the intensity of CL from the luminol-hypochlorite system The hypochlorite was electrogenerated on-line by a constant current electrolysis, resulting in the elimination of the instability of the hypochlorite solution prepared from a commercial reagent of sodium hypochlorite. The detection limits are 0.6 ng/ml for dopamine, 0.8 ng/ml for adrenaline and isoprenaline. The proposed method has been successfully applied to the determination of catecholamines in pharmaceutical injections.

The dopaminergic system and Alzheimer's disease

Alzheimer's disease is a common neurodegenerative disorder in older adults.Despite its prevalence,its pathogenesis remains unclea r.In addition to the most widely accepted causes,which in clude excessive amyloid-beta aggregation,tau hyperphosphorylation,and deficiency of the neurotransmitter acetylcholine,numerous studies have shown that the dopaminergic system is also closely associated with the occurrence and development of this condition.Dopamine is a crucial catecholaminergic neurotransmitter in the human body.Dopamine-associated treatments,such as drugs that target dopamine receptor D and dopamine analogs,can improve cognitive function and alleviate psychiatric symptoms as well as ameliorate other clinical manifestations.Howeve r,therapeutics targeting the dopaminergic system are associated with various adverse reactions,such as addiction and exacerbation of cognitive impairment.This review summarizes the role of the dopaminergic system in the pathology of Alzheimer's disease,focusing on currently available dopamine-based therapies for this disorder and the common side effects associated with dopamine-related drugs.The aim of this review is to provide insights into the potential connections between the dopaminergic system and Alzheimer's disease,thus helping to clarify the mechanisms underlying the condition and exploring more effective therapeutic options.

Crosstalk between catecholamines and erythropoiesis

BACKGROUND： Erythropoiesis is regulated by a range of intrinsic and extrinsic factors, including different cytokines. Recently, the role of catecholamines has been highlighted in the development of erythroid cell lineages. OBJECTIVE： This study focuses on the biological links interconnecting erythroid development and the sympathetic nervous system. The emerging evidence that underscores the role of catecholamines in the regulation of erythropoietin and other erythropoiesis cytokines are thoroughly reviewed, in addition to elements such as iron and the leptin hormone that are involved in erythropoiesis. METHODS： Relevant English-language studies were identified and retrieved from the PubMed search engine （1981-2017） using the following keywords： ＂Erythropoiesis＂, ＂Catecholamines＂, ＂Nervous system＂, and ＂Cytokines.＂ RESULTS： Chronic social stress alters and suppresses erythroid development. However, the physiological release of catecholamines is an additional stimulator of erythropoiesis in the setting of anemia. Therefore, the severity and timing of catecholamine secretion might distinctly regulate erythroid homeostasis. CONCLUSION： Understanding the relationship of catecholamines with different elements of the erythroid islands will be essential to find the tightly regulated production of red blood cells （RBCs） in both chronic and physiological catecholamine activation.

Determination of catecholamines by ion chromatography coupled to acidic potassium permanganate chemiluminescence detection

A simple,fast,sensitive,highly selective and eco-friendly analytical method for the determination of catecholamines in human urine by ion chromatography（IC） with chemiluminescence（CL） detection was described in this paper.Using 12 mmol/L H_2SO_4 without any organic additive as eluent,three catecholamines including epinephrine（EP）,norepinephrine（NE） and dopamine（DA） were well separated on a cation-exchange column.The CL detection was based on the reaction of analytes with acidic potassium permanganate in the presence of formaldehyde as an enhancer.The absence of methanol and acetonitrile in eluent made the proposed method more sensitive and eco-friendly.Under the optimal conditions,the linear range of the proposed method was in the range of 0.02-0.5μg/mL.The limit of detection（LOD） was in the range of 0.6 and 5.1μg/L.The relative standard deviations （RSD） for 0.1μg/mL mixed standard solution were in the range of 0.8-1.9%（n = 11）.The method has been applied to the determination of catecholamines in human urine successfully.Excellent spiked recoveries were achieved for catecholamines ranged from 91.2%to 112.7%.

The relationship between catecholamines levels in mother and fetus, and pathogenesis of pregnancy-induced hypertension

Objective To study the relationship between pregnancy induced hypertension (PIH) and catecholamine levels Methods Catecholamines levels in maternal and fetal blood were determined in 116 patients with PIH and 40 normal control subjects using high performance liquid chromatography The normal control subjects and PIH cases were selected from patients at term pregnancy receiving elective cesarean section Results Plasma norepinephrine (NE) levels were significantly higher in patients with severe PIH than those in control subjects ( P <0 05) Both patients and control subjects had higher NE levels in the umbilical artery blood than in the umbilical vein blood ( P <0 05) NE levels in the umbilical artery blood were five times higher than those in the maternal blood Conclusion The pathogenesis of PIH may relate to catecholamine concentrations in fetus

Simultaneous Determination of Catecholamines and Related Metabolites by Capillary Electrophoresis with Amperometric Detection

An electrophoretic method was developed for the determination of several important catecholamine markers, namely norepinephrine, epinephrine, dopamine, metanephrine, vanillylmandelic acid and homovanillic acid in urine samples. Under the optimum conditions, the six marker compounds could be well separated with the major coexisting interference compound uric acid within 24 rain at a separation voltage of 16 kV in a borate running buffer （80 mmol/L, pH=9.48）. Highly linear response can be obtained over three orders of magnitude for the above markers with the low limits of detection ranging from 1.0 ng/mL to 5.0 ng/mL（S/N=3）. The proposed capillary electrophoresis with amperometric detection（CE-AD） method has been used to simultaneously determine the six catecholamine markers in urine samples of healthy volunteers and patients suffering from different diseases avoiding redundant measurements and high assay cost; and the electrochemical profiles can suggest more diagnostic information of multiple diseases, which provides a promising and convenient entry into primary diagnoses of several clinical diseases.

Role of intestinal glucagon-like peptide-1 in impaired counterregulatory responses to hypoglycemia

Patients with type 1 diabetes mellitus(T1DM)experience multiple episodes of hypoglycemia,resulting in dysfunctional counter-regulatory responses with time.The recent experimental study by Jin et al explored the role of intestinal glucagon-like peptide-1(GLP-1)in impaired counter-regulatory responses to hypoglycemia.They identified intestinal GLP-1 along with GLP-1 receptor(GLP-1R)as the new key players linked with impaired counter-regulatory responses to hypoglycemia in type 1 diabetic mice.They also demonstrated that excessive expression of GLP-1 and GLP-1R was associated with attenuated sympathoadrenal responses and decreased glucagon secretion.The study has enormous clinical relevance as de-fective counter regulation and hypoglycemia unawareness negatively impacts the intensive glycemic management approach in this group of patients.However,the physiological processes must be validated in dedicated human studies to compre-hensively understand the pathophysiology of this complex relationship,and to clarify the true extent of impaired hypoglycemia counter regulation by intestinal GLP-1.For now,following the results of the index study and other similar studies,GLP-1 analogues usage in T1DM must be carefully monitored,as there is an inherent risk of worsening the already impaired counter-regulatory responses in these patients.Further studies in the future could identify other key players in-volved in this clinically relevant interaction.

Sympathetic nervous system activation and heart failure:Current state of evidence and the pathophysiology in the light of novel biomarkers

Heart failure(HF)is a complex clinical syndrome characterized by the activation of at least several neurohumoral pathways that have a common role in maintaining cardiac output and adequate perfusion pressure of target organs and tissues.The sympathetic nervous system(SNS)is upregulated in HF as evident in dysfunctional baroreceptor and chemoreceptor reflexes,circulating and neuronal catecholamine spillover,attenuated parasympathetic response,and augmented sympathetic outflow to the heart,kidneys and skeletal muscles.When these sympathoexcitatory effects on the cardiovascular system are sustained chronically they initiate the vicious circle of HF progression and become associated with cardiomyocyte apoptosis,maladaptive ventricular and vascular remodeling,arrhythmogenesis,and poor prognosis in patients with HF.These detrimental effects of SNS activity on outcomes in HF warrant adequate diagnostic and treatment modalities.Therefore,this review summarizes basic physiological concepts about the interaction of SNS with the cardiovascular system and highlights key pathophysiological mechanisms of SNS derangement in HF.Finally,special emphasis in this review is placed on the integrative and up-to-date overview of diagnostic modalities such as SNS imaging methods and novel laboratory biomarkers that could aid in the assessment of the degree of SNS activation and provide reliable prognostic information among patients with HF.

Locus coeruleus-norepinephrine: basic functions and insights into Parkinson’s disease

The locus coeruleus is a pontine nucleus that produces much of the brain's norepinephrine.Despite its small size,the locus coeruleus is critical for a myriad of functions and is involved in many neurodegenerative and neuropsychiatric disorders.In this review,we discuss the physiology and anatomy of the locus coeruleus system and focus on norepinephrine's role in synaptic plasticity.We highlight Parkinson's disease as a disorder with motor and neuropsychiatric symptoms that may be understood as aberrations in the normal functions of locus coeruleus.

Differential Effects of d, l-Sotalol and d-Sotalol on Isoproterenol-Increased Delayed Rectifier Outward Potassium Current in Guinea Pig Single Ventricular Myocytes

The aim of this study was to compare the effects of d, l-Sotalol and dSotalol on the delayed rectifier K+ outward current in the presence of isoproterenol at different concentrations. Time-dependent delayed rectifier K+ outward currents were measured in isolated guinea pig single myocytes using the whole-cell configuration of the patch-clamp technique. Currents were measured in response to 300 ms depolarizing pulses from a holding potential of -40 mV in three experimental protocols [control, isoproterenol (10^(9)mol/L - 10^(-6) mol/L ), and isoproterenol (10^(-9)mol/L - 10^(-6)mol/L ) plus either d, l-Sotalol (10^(-4) mol/L) or d-Sotalol (10^(-4) mol/L)]. IK tail currents were measured upon repolarization to -40 mV. It was found that Ik was significantly amplified in the presence. of isoproterenol (10^(-9) mol/L- 10^(-6) mol/L) plus d-Sotalol. At 10-8 mol/L isoproterenol, Ik was increased by 92. 7%±17. 1 % (P<0. 05) and 54. 3 %±13. 4 % after d-Sotalol addition (P<0. 05). In contrast, d, l-Sotalol completely conteracted the increase of iK by isoproterenol (<10^(-8) mol/L), and compared to control, Ic was decreased by 35. 6 % ±8. 1% at 10^(-8) mol/L isoproterenol plus d, l-Sotalol (P<0. 05). It is concluded that the β-adrenergic blocking property of d, l-Sotalol but not that of dSotalol maintains the delayed rectifier K+ outward current blockade in the presence of isoproterenol in guinea pig myocytes. This might contribute to a superior antiarrhythmic efficacy as compared to d-Sotalol.

Risks of suicidality in adult patients with epilepsy

AIM: To determine the prevalence and risks of suicidality in a group of patients with epilepsy. METHODS: Included were 200 adult patients and 100 matched healthy subjects. The clinical interview using The Diagnostic and Statistical Manual of Mental Disorders(4th edition), Beck Depression Inventory(2nd edition)(BDI-Ⅱ), Hamilton Anxiety Rating Scale(HAM-A), Yale-Brown Obsessive Compulsive Scale(Y-BOCS) and Eysenck Personality Questionnaire-Revised Rating Scale testings were used for diagnosis and assessment of severity of psychiatric symptoms. Blood concentrations of serotonin, catecholamines and dopamine were also measured.RESULTS: Suicidality was reported in 35%(compared to 9% for controls), of them 80%, 72.86%, 55.71% and 52.9% had depression, anxiety, obsession and aggression respectively. Patients with suicidality had higher scores of BDI-Ⅱ(P = 0.0001), HAM-A(P = 0.0001), and Y-BOCS(P = 0.037) and lower scores of psychotic(P = 0.0001) and extroversion(P = 0.025) personality traits. Regardless the presence or absence of suicidality, patients with epilepsy had low serotonin(P = 0.006), noradrenaline(P = 0.019) and adrenaline(P = 0.0001) levels. With suicidality, significant correlations were identified between:(1) age and scores of BDI-Ⅱ(r = 0.235, P = 0.0001) and HAM-A(r = 0.241, P = 0.046);(2) age at onset and concentrations of noradrenaline(r =-0.502, P = 0.024);(3) duration of illness and scores of BDI-Ⅱ(r = 0.247, P = 0.041), Y-BOCS(r = 0.270, P = 0.025) and neurotic personality trait(r =-0.284, P = 0.018); and(4) doses of antiepileptic drugs and scores of psychotic personality traits(r =-0.495, P = 0.006 for carbamazepine; r =-0.508, P = 0.0001 for valproate).CONCLUSION: This is the first study which systematically estimated the prevalence and risks of suicidality in a homogenous group of patients with epilepsy. This study emphasizes the importance of epilepsy itself as a risk for suicidality and not its treatment.

Apical Ballooning Syndrome: Recent Insights from a Consecutive Series of 104 Patients

Apical ballooning syndrome (Takotsubo cardiomyopathy) is an increasingly recognized form of acute systolic dysfunction which is usually reversible. It typically occurs in post-menopausal women following a major psychological stressor. We conducted a single center, retrospective analysis of all hospitalized patients from 2001-2012 and found 104 patients who met the diagnostic criteria for apical ballooning. In this current largest series of its kind, 83% of the patients were women. Among both men and women, an antecedent stressor was not always identified. The exact pathophysiologic mechanism resulting in apical ballooning remains poorly understood. These findings challenge the paradigm that catecholamine cardiotoxicity in the setting of relative estrogen deficiency results in the cardiomyopathy.

Natural killer cells responsiveness to physical exercise: A brief review

Natural killer cells (NK) are a group of peripheral blood lymphocytes which display cytotoxic activity against a wide range of tumour cells. They are a consistent part of the inflammatory response that is activated when either internal or external injuries occur as they are able to synthesize perforins. An important role is played by NK cells in the host defence against tumours without expressing any antigen-binding recaptor in their membrane which, however, distinguish T and B lymphocytes. NK activity appears early in the immune response, thus providing immediate protection during the time required for the activation and proliferation of cytotoxic T lymphocytes and for their differentiation into functional cells. Even though much research regarding the effects of aerobic training exercise on NK cell numbers and function, there appears to be much controversy regarding its effect. NK cells are rapidly mobilized into circulation in response to acute exercise, most likely by increased shear stress and catecholamine-induced down-regulation of adhesion molecule expression. However, tissue injury and inflammation which often accompanies strenuous exercise have been associated to post-exercise NK cell suppression. Scientific evidence indicates exercise-induced changes in NK cell redistribution and function should be strongly influenced by stress hormones including catecholamines, cortisol and prolactin as well as by soluble mediators such as cytokines and prostaglandins. The role of exercise therapy in cancer patients and survivors rehabilitation is becoming increasingly important as it is thought to modulate immunity and inflammation. However, more knowledge about the effects of exercise on immune function in these patients is needed.

Gene Regulation of Catecholamine Biosynthetic Enzymes by Nitric Oxide in PC12 Cells

Nitric oxide (NO) regulates a wide range of physiological processes. Recent studies show that NO can regulate the release of catecholamines (CA) from the adrenal medulla. In the current study, the PC12 cell line was used to examine the effect of NO on the regulation of the CA biosynthetic enzymes: tyrosine hydroxylase (TH), dopamine-β-hydroxylase (DBH) and phenylethanolamine Nmethyltransferase (PNMT). Treatment of PC12 cells with the NO donor, sodium nitroprusside (SNP) for 6 hours significantly increased TH, DBH and PNMT mRNA levels. In addition, NO potentiates the regulation of gene expression of all three CA biosynthetic enzymes by glucocorticoids and cholinergic agonists. The signaling pathways involved in NO regulation of CA biosynthetic enzymes were investigated with the use of specific kinase activators and inhibitors, with results supporting a contributing role of PKA, PKC and PKG in SNP-mediated induction for all three CA genes (p < 0.01). In addition, inhibitors of transcription and translation inhibited SNP-mediated induction of all three genes (p < 0.001) suggesting that both transcriptional and translational mechanisms may be involved in CA gene regulation by NO. Results from this study show that in addition to regulating CA biosynthetic enzymes, NO can also potentiate cholinergic and glucocorticoid activation of CA genes.

Recovery of nigrostriatal dopaminergic system insufficiency by allotransplantation of embryonic brain tissue

In an experiment in rats with electrolytic lesion of the compact part of substantia nigra (SN) and after allotransplantation of the embryonic tissue of SN in the caudate nucleus the features of movement and emotional behavior in the Open Field Test (OFT), the rotation movements caused by an administration of amphetamine, a content of catecholamines in the caudate nucleus, hypothalamus and blood plasma have been investigated. It is shown that the electrolytic lesion causes violations of the statokinetic reflexes, the horizontal and the vertical movement activity, enhances the rotatory behavior, slow the orienttate-searching and the emotional reactions that combined with disbalance in dopamine-and noradrenalinetransmitter systems functioning. Allotransplantation of the embryonic dofaminsynthesizing brain tissue contributes to the restoration of movement activeity and its specific neurotransmitter ensuring.