A Common Tag Nucleotide Variant in MMP7 Promoter Increases Risk for Hypertension via Enhanced Interactions With CREB (Cyclic AMP Response Element-Binding Protein) Transcription Factor

MMP (matrix metalloproteinase)-7-a potent extracellular matrix degrading enzyme-is emerging as a new regulator of cardiovascular diseases. However, potential contributions of MMP7 genetic variations to hypertension remain unknown. In this study, we probed for the association of a tag single-nucleotide polymorphism in the MMP7 promoter (-181A/G; rs11568818) with hypertension in an urban South Indian population (n=1501). The heterozygous AG genotype significantly increased risk for hypertension as compared with the wild-type AA genotype (odds ratio, 1.60 [95% CI, 1.25-2.06]; P=2.4×10^-4); AG genotype carriers also displayed significantly higher diastolic blood pressure and mean arterial pressure than wild-type AA individuals. The study was replicated in a North Indian population (n=949) (odds ratio, 1.52 [95% CI, 1.11-2.09]; P=0.01). Transient transfection experiments using MMP7 promoter-luciferase reporter constructs revealed that the variant -181G allele conferred greater promoter activity than the -181A allele. Computational prediction and structure-based conformational and molecular dynamics simulation studies suggested higher binding affinity for the CREB (cyclic AMP response element-binding protein) to the -181G promoter. In corroboration, overexpression/downregulation of CREB and chromatin immunoprecipitation experiments provided convincing evidence for stronger binding of CREB with the -181G promoter. The -181G promoter also displayed enhanced responses to hypoxia and epinephrine treatment. The higher promoter activity of -181G allele translated to increased MMP7 protein level, and MMP7-181AG heterozygous individuals displayed elevated plasma MMP7 levels, which positively correlated with blood pressure. In conclusion, the MMP7 A-181G promoter polymorphism increased MMP7 expression under pathophysiological conditions (hypoxic stress and catecholamine excess) via increased interactions with CREB and enhanced the risk for hypertension in its carriers.

BDNF downregulates β-adrenergic receptor-mediated hypotensive mechanisms in the paraventricular nucleus of the hypothalamus

Brain-derived neurotrophic factor (BDNF) is upregulated in the paraventricular nucleus of the hypothalamus (PVN) in response to hypertensive stimuli such as stress and hyperosmolality, and BDNF acting in the PVN plays a key role in elevating sympathetic activity and blood pressure. However, downstream mechanisms mediating these effects remain unclear. We tested the hypothesis that BDNF increases blood pressure, in part by diminishing inhibitory hypotensive input from nucleus of the solitary tract (NTS) catecholaminergic neurons projecting to the PVN. Male Sprague-Dawley rats received bilateral PVN injections of viral vectors expressing either green fluorescent protein (GFP) or BDNF and bilateral NTS injections of vehicle or anti-dopamine-β-hydroxylase-conjugated saporin (DSAP), a neurotoxin that selectively lesions noradrenergic and adrenergic neurons. BDNF overexpression in the PVN without NTS lesioning significantly increased mean arterial pressure (MAP) in awake animals by 18.7 ± 1.8 mmHg. DSAP treatment also increased MAP in the GFP group, by 9.8 ± 3.2 mmHg, but failed to affect MAP in the BDNF group, indicating a BDNF-induced loss of NTS catecholaminergic hypotensive effects. In addition, in α-chloralose-urethane-anesthetized rats, hypotensive responses to PVN injections of the β-adrenergic agonist isoprenaline were significantly attenuated by BDNF overexpression, whereas PVN injections of phenylephrine had no effect on blood pressure. BDNF treatment was also found to significantly reduce β₁-adrenergic receptor mRNA expression in the PVN, whereas expression of other adrenergic receptors was unaffected. In summary, increased BDNF expression in the PVN elevates blood pressure, in part by downregulating β-receptor signaling and diminishing hypotensive catecholaminergic input from the NTS to the PVN.NEW & NOTEWORTHY We have shown that BDNF, a key hypothalamic regulator of blood pressure, disrupts catecholaminergic signaling between the NTS and the PVN by reducing the responsiveness of PVN neurons to inhibitory hypotensive β-adrenergic input from the NTS. This may be occurring partly via BDNF-mediated downregulation of β₁-adrenergic receptor expression in the PVN and results in an increase in blood pressure.

Ankyrin-B Q1283H Variant Linked to Arrhythmias Via Loss of Local Protein Phosphatase 2A Activity Causes Ryanodine Receptor Hyperphosphorylation

Supplemental Digital Content is available in the text.

Background:

Human loss-of-function variants of ANK2 (ankyrin-B) are linked to arrhythmias and sudden cardiac death. However, their in vivo effects and specific arrhythmogenic pathways have not been fully elucidated.

Methods:

We identified new ANK2 variants in 25 unrelated Han Chinese probands with ventricular tachycardia by whole-exome sequencing. The potential pathogenic variants were validated by Sanger sequencing. We performed functional and mechanistic experiments in ankyrin-B knockin (KI) mouse models and in single myocytes isolated from KI hearts.

Results:

We detected a rare, heterozygous ANK2 variant (p.Q1283H) in a proband with recurrent ventricular tachycardia. This variant was localized to the ZU5^C region of ANK2, where no variants have been previously reported. KI mice harboring the p.Q1283H variant exhibited an increased predisposition to ventricular arrhythmias after catecholaminergic stress in the absence of cardiac structural abnormalities. Functional studies illustrated an increased frequency of delayed afterdepolarizations and Ca²⁺ waves and sparks accompanied by decreased sarcoplasmic reticulum Ca²⁺ content in KI cardiomyocytes on isoproterenol stimulation. The immunoblotting results showed increased levels of phosphorylated ryanodine receptor Ser2814 in the KI hearts, which was further amplified on isoproterenol stimulation. Coimmunoprecipitation experiments demonstrated dissociation of protein phosphatase 2A from ryanodine receptor in the KI hearts, which was accompanied by a decreased binding of ankyrin-B to protein phosphatase 2A regulatory subunit B56α. Finally, the administration of metoprolol or flecainide decreased the incidence of stress-induced ventricular arrhythmias in the KI mice.

Conclusions:

ANK2 p.Q1283H is a disease-associated variant that confers susceptibility to stress-induced arrhythmias, which may be prevented by the administration of metoprolol or flecainide. This variant is associated with the loss of protein phosphatase 2A activity, increased phosphorylation of ryanodine receptor, exaggerated delayed afterdepolarization-mediated trigger activity, and arrhythmogenesis.

Propranolol protects cerebral autoregulation and reduces hippocampal neuronal cell death through inhibition of interleukin-6 upregulation after traumatic brain injury in pigs

BACKGROUND

Traumatic brain injury (TBI) is associated with reduced cerebral blood flow and impaired autoregulation after TBI, which may lead to poor outcome. Clinical evidence has implicated neurological injuries and associated neuroinflammation as causes of cardiac dysfunction. Studies on newborn pigs show an association of elevated catecholamines with a sex-dependent impairment of cerebral autoregulation after TBI. One strategy to decrease sympathetic hyperactivity is pharmacological intervention with beta blockade. We tested the hypothesis that propranolol would prevent the impairment of cerebral autoregulation and tissue changes after TBI via inhibition of interleukin-6 (IL-6) upregulation.

METHODS

Using newborn pigs of both sexes equipped with a closed cranial window, TBI was induced via lateral fluid percussion injury. Propranolol was administered at 1 h post-TBI. Analyses included cerebral autoregulation (pial artery reactivity) before and 4 h post-TBI, CSF IL-6 analysed (enzyme-linked immunosorbent assay), and histopathology at 4 h post-TBI.

RESULTS

Propranolol administration prevented impairment of hypotensive dilation in both male and female newborn pigs after fluid percussion injury, which was paralleled by reduced upregulation of IL-6 in the CSF. Moreover, propranolol prevented neuronal cell death in cornu amonis (CA)1 and CA3 hippocampus equivalently in male and female pigs after TBI. Papaverine-induced dilation was unchanged by TBI and propranolol.

CONCLUSIONS

These data indicate that sympathetic hyperactivity noted after TBI can be limited by propranolol administration to result in improved brain outcome post-injury via block of IL-6 upregulation, and this effect is irrespective of sex.

Ca2+-independent but voltage-dependent quantal catecholamine secretion (CiVDS) in the mammalian sympathetic nervous system

Action potential-induced vesicular exocytosis is considered exclusively Ca²⁺ dependent in Katz's Ca²⁺ hypothesis on synaptic transmission. This long-standing concept gets an exception following the discovery of Ca²⁺-independent but voltage-dependent secretion (CiVDS) and its molecular mechanisms in dorsal root ganglion sensory neurons. However, whether CiVDS presents only in sensory cells remains elusive. Here, by combining multiple independent recordings, we report that [1] CiVDS robustly presents in the sympathetic nervous system, including sympathetic superior cervical ganglion neurons and slice adrenal chromaffin cells, [2] uses voltage sensors of Ca²⁺ channels (N-type and novel L-type), and [3] contributes to catecholamine release in both homeostatic and fight-or-flight like states; [4] CiVDS-mediated catecholamine release is faster than that of Ca²⁺-dependent secretion at the quantal level and [5] increases Ca²⁺ currents and contractility of cardiac myocytes. Together, CiVDS presents in the sympathetic nervous system with potential physiological functions, including cardiac muscle contractility.

Angiotensin II mediates the axonal trafficking of tyrosine hydroxylase and dopamine β-hydroxylase mRNAs and enhances norepinephrine synthesis in primary sympathetic neurons

In the sympatho-adrenal system, angiotensin II (Ang II) acts as a key neuromodulatory component. At sympathetic nerve terminals, Ang II influences sympathetic transmission by enhancing norepinephrine (NE) synthesis, facilitating NE release and inhibiting NE uptake. Previously, it was demonstrated that tyrosine hydroxylase (TH) mRNA is trafficked to the distal axons of primary superior cervical ganglia (SCG) neurons, directed by a cis-acting regulatory element (i.e. zipcode) located in the 3'UTR of the transcript. Results of metabolic labeling studies established that the mRNA is locally translated. It was further shown that the axonal trafficking of the mRNA encoding the enzyme plays an important role in mediating dopamine (DA) and NE synthesis and may facilitate the maintenance of axonal catecholamine levels. In the present study, the hypothesis was tested that Ang II induces NE synthesis in rat primary SCG neurons via the modulation of the trafficking of the mRNAs encoding the catecholamine synthesizing enzymes TH and dopamine β-hydroxylase (DBH). Treatment of SCG neurons with the Ang II receptor type 1 (AT1R) agonist, L-162,313, increases the axonal levels of TH and DBH mRNA and protein and results in elevated NE levels. Conversely, treatment of rat SCG neurons with the AT1R antagonist, Eprosartan, abolished the L-162,313-mediated increase in axonal levels of TH and DBH mRNA and protein. In a first attempt to identify the proteins involved in the Ang II-mediated axonal transport of TH mRNA, we used a biotinylated 50-nucleotide TH RNA zipcode as bait in the affinity purification of TH zipcode-associated proteins. Mass spectrometric analysis of the TH zipcode ribonucleoprotein (RNP) complex immune-purified from SCG neurons led to the identification of 163 somal and 127 axonal proteins functionally involved in binding nucleic acids, the translational machinery or acting as subunits of cytoskeletal and motor proteins. Surprisingly, immune-purification of the TH axonal trafficking complex, results in the acquisition of DBH mRNA, suggesting that these mRNAs maybe transported to the axon together, possibly in the same RNP complex. Taken together, our results point to a novel mechanism by which Ang II participates in the regulation of axonal synthesis of NE by modulating the local trafficking and expression of TH and DBH, two key enzymes involved in the catecholamine biosynthetic pathway.

[Clinical effect of carvedilol in treatment of children with severe hand-foot-mouth disease caused by enterovirus 71 infection]

OBJECTIVE

To study the clinical effect of carvedilol in the treatment of children with severe hand-foot-mouth disease (HFMD) caused by enterovirus 71 (EV71) infection.

METHODS

A retrospective analysis was performed for the clinical data of 86 children with severe HFMD caused by EV71 infection who were admitted to the hospital from April 2016 to August 2017. According to whether carvedilol was used, the children were divided into conventional treatment group with 51 children and carvedilol treatment group with 35 children. A total of 56 healthy children who underwent physical examination at the outpatient service during the same period were enrolled as the control group. The two treatment groups were compared in terms of clinical features and levels of catecholamines (norepinephrine, adrenaline and dopamine), and the levels of catecholamines were compared between these two treatment groups and the control group.

RESULTS

Before treatment, the conventional treatment group and the carvedilol treatment group had significantly higher levels of norepinephrine and adrenaline than the control group (P<0.05). After treatment, both the conventional treatment group and the carvedilol treatment group had significant reductions in norepinephrine, adrenaline, blood glucose, systolic pressure, diastolic pressure, heart rate, body temperature and leukocyte count (P<0.05). Compared with the conventional treatment group, the carvedilol treatment group had significantly lower dopamine level, blood glucose, heart rate and respiratory rate after treatment (P<0.05).

CONCLUSIONS

Changes in norepinephrine and adrenaline might be involved in the pathogenesis of severe HFMD caused by EV71 infection. Carvedilol, in addition to the conventional treatment, can improve respiration, heart rate and blood glucose in children with severe HFMD caused by EV71 infection.

[Clinical effect of carvedilol in treatment of children with severe hand-foot-mouth disease caused by enterovirus 71 infection]

OBJECTIVE

To study the clinical effect of carvedilol in the treatment of children with severe hand-foot-mouth disease (HFMD) caused by enterovirus 71 (EV71) infection.

METHODS

A retrospective analysis was performed for the clinical data of 86 children with severe HFMD caused by EV71 infection who were admitted to the hospital from April 2016 to August 2017. According to whether carvedilol was used, the children were divided into conventional treatment group with 51 children and carvedilol treatment group with 35 children. A total of 56 healthy children who underwent physical examination at the outpatient service during the same period were enrolled as the control group. The two treatment groups were compared in terms of clinical features and levels of catecholamines (norepinephrine, adrenaline and dopamine), and the levels of catecholamines were compared between these two treatment groups and the control group.

RESULTS

Before treatment, the conventional treatment group and the carvedilol treatment group had significantly higher levels of norepinephrine and adrenaline than the control group (P<0.05). After treatment, both the conventional treatment group and the carvedilol treatment group had significant reductions in norepinephrine, adrenaline, blood glucose, systolic pressure, diastolic pressure, heart rate, body temperature and leukocyte count (P<0.05). Compared with the conventional treatment group, the carvedilol treatment group had significantly lower dopamine level, blood glucose, heart rate and respiratory rate after treatment (P<0.05).

CONCLUSIONS

Changes in norepinephrine and adrenaline might be involved in the pathogenesis of severe HFMD caused by EV71 infection. Carvedilol, in addition to the conventional treatment, can improve respiration, heart rate and blood glucose in children with severe HFMD caused by EV71 infection.

A large pheochromocytoma requiring aortic and inferior vena caval reconstruction: A case report

RATIONALE

It is difficult to discriminate malignant pheochromocytoma (PCC) from benign PCC. The requirement of abdominal aortic and inferior vena cava reconstruction is extremely rare.

PATIENT CONCERNS

We here report a case of a large pheochromocytoma in a 56-year-old woman who complained of only hand trembling and had no hypertension or other symptoms. The operation was difficult because of a tight adhesion to the circumference of great vessels. A replacement of the aortocaval vessels with grafts was necessary to remove the tumor completely.

DIAGNOSES

Ultrasonography, computed tomography (CT), and catecholamine assay revealed suspecting the retroperitoneal PCC.

INTERVENTIONS

Tumor excision and reconstruction of the abdominal aorta and inferior vena cava by externally supported polytetrafluoroethylene (ePTFE) vessels were successfully performed.

OUTCOMES

A follow-up CT angiography showed no recurrence and graft vessels presented good patency after 7years. Catecholamine in urine and serum assay was normal.

LESSONS

The complete resection of the tumor and infiltrated great vessels were necessary for the long-term survival of patients with a large PCC. The ePTFE graft is a good substitute for vessel reconstruction.

Catecholamine-Induced Cardiomyopathy in Pheochromocytoma: How to Manage a Rare Complication in a Rare Disease?

Pheochromocytomas and paragangliomas (PHEOs) are rare neuroendocrine tumors. Clinical manifestations include different cardiovascular signs and symptoms, which are related to excessive secretion of catecholamines. Catecholamine-induced cardiomyopathy in PHEO (CICMPP) is a rare but dreaded complication of PHEO. Once patient is diagnosed with this condition, the prognosis is worse and a surgical risk is much higher than expected. This article focuses on how catecholamines affect the heart and the pathophysiologic mechanism of CICMPP. The cardiovascular responses to catecholamine depend mostly on which catecholamine is released as well as the amount of catecholamine that is released. The acute release of norepinephrine and epinephrine from PHEO increases heart rate, systemic vascular resistance, myocardial contractility, and reduces venous compliance. The excessive adrenergic stimulation by catecholamine results in severe vasoconstriction and coronary vasospasm, myocardial ischemia, and subsequently damage, and necrosis. Chronically elevated catecholamine levels lead to significant desensitization of cardiac β-adrenoceptors. The increased levels of the enzyme β-adrenoceptors kinase (βARK) in the heart seems to mediate these biochemical and physiological changes that are consistently correlated with attenuated responsiveness to catecholamine stimulation. Through these mechanisms different types of cardiomyopathy (CMP) can be formed. This review discusses extensively the 3 types of cardiomyopathies that can be present in a PHEO patient. It also provides the clinical presentation and diagnostic and therapeutic algorithm in managing patients with CICMPP.

Ursolic acid modulates MMPs, collagen-I, α-SMA, and TGF-β expression in isoproterenol-induced myocardial infarction in rats

In the present study, the modulatory effect of ursolic acid (UA) on cardiac fibrosis and mitochondrial and lysosomal enzymes activity in isoproterenol-induced myocardial infarction (MI) in rats were examined. Isoproterenol hydrochloride (ISO; 85 mg/kg body weight) was administered subcutaneously for first two consecutive days. ISO-induced MI in rats significantly decreased the activities of mitochondrial tricarboxylic acid cycle enzymes and respiratory chain enzymes while increased the activities of lysosomal glycohydrolases and cathepsins. The expression of matrix metalloproteinase 2 (MMP-2), MMP-9, collagen type I, α-smooth muscle actin (α-SMA), and transforming growth factor-β (TGF-β) were upregulated in ISO-induced MI in rats. UA administration to rats showed increased activities of mitochondrial tricarboxylic acid cycle enzymes and respiratory chain enzymes and decreased activities of lysosomal glycohydrolases and cathepsins in ISO-induced rats. Furthermore, expression of MMP-2, MMP-9, collagen type I, α-SMA, and TGF-β downregulated in UA-administered rats. Thus, our results demonstrate that UA has an anti-fibrotic effect and attenuates the mitochondrial and lysosomal dysfunction in ISO-induced MI in rats.

Brown adipose activation and reversible beige coloration in adipose tissue with multiple accumulations of 18F-fluorodeoxyglucose in sporadic paraganglioma: A case report

In pheochromocytoma/paraganglioma, nontumorous high 18F-fluorodeoxyglucose accumulations are observed in both beige and brown adipose tissues. Recognizing this feature of 18F-fluorodeoxyglucose accumulation can help physicians make precise diagnoses and help them avoid the pitfalls of a false-positive 18F-fluorodeoxyglucose positron emission tomography result, preventing unnecessary interventions.

Allelic variation in dopamine D2 receptor gene is associated with attentional impulsiveness on the Barratt Impulsiveness Scale (BIS-11)

OBJECTIVES

Previous studies have postulated that noradrenergic and/or dopaminergic gene variations are likely to underlie individual differences in impulsiveness, however, few have shown this. The current study examined the relationship between catecholamine gene variants and self-reported impulsivity, as measured by the Barratt Impulsiveness Scale (Version 11; BIS-11) Methods: Six hundred and seventy-seven non-clinical adults completed the Barratt Impulsiveness Scale (BIS-11). DNA was analysed for a set of 142 single-nucleotide polymorphisms (SNPs) across 20 autosomal catecholamine genes. Association was tested using an additive regression model with permutation testing used to control for the influence of multiple comparison.

RESULTS

Analysis revealed an influence of rs4245146 of the dopamine D2 receptor (DRD2) gene on the BIS-11 attention first-order factor, such that self-reported attentional impulsiveness increased in an additive fashion with each copy of the T allele.

CONCLUSIONS

These findings provide preliminary evidence that allelic variation in DRD2 may influence impulsiveness by increasing the propensity for attentional lapses.

Heritable Differences in Catecholamine Signaling Modulate Susceptibility to Trauma and Response to Methylphenidate Treatment: Relevance for PTSD

Alterations in cortical catecholamine signaling pathways can modulate acute and enduring responses to trauma. Heritable variation in catecholamine signaling is produced by a common functional polymorphism in the catechol-O-methyltransferase (COMT), with Val carriers exhibiting greater degradation of catecholamines than Met carriers. Furthermore, it has recently been suggested that drugs enhancing cortical catecholamine signaling may be a new therapeutic approach for posttraumatic stress disorder (PTSD) patients. We hypothesized that heritable differences in catecholamine signaling regulate the behavioral response to trauma, and that methylphenidate (MPD), a drug that preferentially blocks catecholamine reuptake in the prefrontal cortex (PFC), exerts COMT-dependent effects on trauma-induced behaviors. We first examined the contribution of the functional mutation COMTval158met to modulate enduring behavioral responses to predator stress in a unique "humanized" COMTval158met mouse line. Animals were exposed to a predator (cat) for 10 min and enduring avoidance behaviors were examined in the open field, light-dark box, and "trauma-reminder" tests 1-2 weeks later. Second, we examined the efficacy of chronic methylphenidate to reverse predator stress effects and if these effects were modulated by COMTval158met genotype. Mice were exposed to predator stress and began treatment with either saline or methylphenidate (3 mg/kg/day) 1 week after stress until the end of the testing [avoidance behaviors, working memory, and social preference (SP)]. In males, predator stress and COMTval158met had an additive effect on enduring anxiety-like behavior, with Val stressed mice showing the strongest avoidance behavior after stress compared to Met carriers. No effect of COMT genotype was observed in females. Therefore methylphenidate effects were investigated only in males. Chronic methylphenidate treatment reversed the stress-induced avoidance behavior and increased social investigation independently of genotype. Methylphenidate effects on working memory, however, were genotype-dependent, decreasing working memory in non-stressed Met carriers, and improving stress-induced working memory deficit in Val carriers. These results suggest that heritable variance in catecholamine signaling modulates the avoidance response to an acute trauma. This work supports recent human findings that methylphenidate might be a therapeutic alternative for PTSD patients and suggests that methylphenidate effects on anxiety (generalized avoidance, social withdrawal) vs. cognitive (working memory) symptoms may be modulated through COMT-independent and dependent mechanisms, respectively.

Acute hypotension induced by suction of cystic fluid containing extremely high concentrations of catecholamines during resection of giant pheochromocytoma

Introduction

Since pheochromocytomas present with various complications due to catecholamine hypersecretion, their perioperative management needs special attention.

Case presentation

A 45‐year‐old man visited our hospital with a complaint of abdominal swelling. Radiological and endocrinological assessments determined the tumor as a giant (>20 cm) cystic pheochromocytoma. After administration of doxazosin, the patient underwent radical surgery. Since the tumor was extremely large and fixed to surrounding structures, we punctured it and aspirated cystic fluid to improve the tumor's mobility. However, during the aspiration, the patient developed acute hypotension, which could be reversed by suction withdrawal and vasopressor administration. A similar event occurred during a second aspiration. Eventually, the tumor was successfully excised with negative surgical margin. The cystic fluid proved to contain extremely high concentrations of catecholamines, which might result in the hypotension.

Conclusion

We report the first case who developed acute hypotension due to aspiration of cystic fluid from giant pheochromocytoma.

A Novel Biomarker Renalase and Its Relationship with its Substrates in Schizophrenia

Background

Schizophrenia, particularly the form related to excessive dopamine (DA), is a chronic psychotic disorder affecting millions of people worldwide. Renalase metabolizes its catecholamine (CA) substrates, including DA, suggesting that there might be an association between renalase levels and schizophrenia occurrence. Therefore, the current study aimed to evaluate the renalase and CA levels in the serum of patients with schizophrenia.

Methods

The study was conducted with thirty-three schizophrenia patients and an age- and gender-matched group of thirty-one controls. Renalase and CA levels were measured by using an enzyme-linked immunosorbent assay (ELISA).

Results

Renalase levels were significantly lower in the schizophrenia patients than in the control group (p<0.05), whereas DA levels were significantly higher (p<0.05). The epinephrine (Epi) levels of both groups were similar (p=0.186), while the norepinephrine levels in patients with schizophrenia were significantly lower than those in the control group (p<0.05). The areas under the curves for the renalase-dopamine, renalase-norepinephrine and renalase-epinephrine ratios were 0.805, 95% confidence interval (CI): 0.699–0.912 (p<0.001); 0.726, 95% CI: 0.594–0.859 (p=0.032); and 0.656, 95% CI: 0.520–0.791 (p=0.02).

Conclusions

The high DA levels in patients with schizophrenia might be due to low renalase levels. Renalase enzyme levels may play a substantial role in the pathophysiology of schizophrenia. Thus, this enzyme might be a new future target for the treatment and diagnosis of schizophrenia after intrabrain renalase and DA dynamics have been further evaluated.

Impact of Extrinsic and Intrinsic Hypoxia on Catecholamine Biosynthesis in Absence or Presence of Hif2α in Pheochromocytoma Cells

Pheochromocytomas and paragangliomas (PPGLs) with activated pseudohypoxic pathways are associated with an immature catecholamine phenotype and carry a higher risk for metastasis. For improved understanding of the underlying mechanisms we investigated the impact of hypoxia and pseudohypoxia on catecholamine biosynthesis in pheochromocytoma cells naturally lacking Hif2α (MPC and MTT) or expressing both Hif1α and Hif2α (PC12). Cultivation under extrinsic hypoxia or in spheroid culture (intrinsic hypoxia) increased cellular dopamine and norepinephrine contents in all cell lines. To distinguish further between Hif1α- and Hif2α-driven effects we expressed Hif2α in MTT and MPC-mCherry cells (naturally lacking Hif2α). Presence of Hif2α resulted in similarly increased cellular dopamine and norepinephrine under hypoxia as in the control cells. Furthermore, hypoxia resulted in enhanced phosphorylation of tyrosine hydroxylase (TH). A specific knockdown of Hif1α in PC12 diminished these effects. Pseudohypoxic conditions, simulated by expression of Hif2α under normoxia resulted in increased TH phosphorylation, further stimulated by extrinsic hypoxia. Correlations with PPGL tissue data led us to conclude that catecholamine biosynthesis under hypoxia is mainly mediated through increased phosphorylation of TH, regulated as a short-term response (24–48 h) by HIF1α. Continuous activation of hypoxia-related genes under pseudohypoxia leads to a HIF2α-mediated phosphorylation of TH (permanent status).

A High-Affinity Fluorescent Sensor for Catecholamine: Application to Monitoring Norepinephrine Exocytosis

A fluorescent sensor for catecholamines, NS510, is presented. The sensor is based on a quinolone fluorophore incorporating a boronic acid recognition element that gives it high affinity for catecholamines and a turn-on response to norepinephrine. The sensor results in punctate staining of norepinephrine-enriched chromaffin cells visualized using confocal microscopy indicating that it stains the norepinephrine in secretory vesicles. Amperometry in conjunction with total internal reflection fluorescence (TIRF) microscopy demonstrates that the sensor can be used to observe destaining of individual chromaffin granules upon exocytosis. NS510 is the highest affinity fluorescent norepinephrine sensor currently available and can be used for measuring catecholamines in live-cell assays.

Stress resilience evidenced by grooming behaviour and dopamine levels in male mice selected for high and low immobility using the tail suspension test

Grooming behaviour has different functions on many species during development and can be observed and affected during periods of stress. By selecting male mice with high (HI) and low (LI) immobility traits in the tail suspension test, a screening for antidepressant drugs, we investigate how these phenotypes associated with grooming behaviour may be influenced by the effects of repeated restraint stress. For this we used the sucrose preference test and the splash test in a novel and a familiar cage performed before and after exposure to 2 days of restraint stress. Animals were submitted to an additional day of restraint stress before the hypothalamus, prefrontal cortex and midbrain extraction for dopamine activity analysis. Corticosterone analysis was made in three distinct moments: without stress (prior first restraint session), immediately after the last restrain, and 1 hr after the last restrain episode. Compared to LI group, HI animals exhibited an increased frequency and decreased time of grooming in the familiar cage. In the novel cage, stress increased frequency and time of grooming of HI animals compared to LI. Corticosterone levels were increased in HI animals after 3 days of stress. Lower hypothalamic dopaminergic activity without stress and decreased hypothalamic dopaminergic activity immediately after stress in HI group were observed. The HI group displayed decreased prefrontal cortex dopaminergic activity and increased activity in the mesolimbic area. We proposed that through the influence of stress the two phenotypes manifested as a resilient (LI) and a not resilient (HI) trait in response to restraint stress.

Responses of Plasma Catecholamine, Serotonin, and the Platelet Serotonin Transporter to Cigarette Smoking

Cigarette smoking is one of the major causes of coronary heart disease with a thirty percent mortality rate in the United States. Cigarette smoking acting on the central nervous system (CNS) to stimulate the sympathetic nervous system (SNS) through, which facilitates the secretion of serotonin (5-HT) and catecholamines to supraphysiological levels in blood. The enhanced levels of 5-HT and catecholamines in smokers’ blood are associated with increases in G protein-coupled receptor signaling and serotonylation of small GTPases, which in turn lead to remodeling of cytoskeletal elements to enhance granule secretion and promote unique expression of sialylated N-glycan structures on smokers’ platelets. These mechanisms enhance aggregation and adhesion of smokers’ platelets relative to those of non-smokers. This review focuses on the known mechanisms by which 5-HT and SERT, in coordinated signaling with catecholamines, impacts cigarette smokers’ platelet biology.

Mechanical Efficiency at Different Exercise Intensities Among Adolescent Boys With Different Body Fat Levels

This study investigated the mechanical efficiency (ME) and associated factors in obese, overweight, and normal-weight adolescent boys during incremental cycle exercise test to exhaustion. Forty-five sedentary adolescent boys (13–14 years old) were separated in three groups according to the percentage of fat mass as follows: 15 normal-weight (NW) (body fat: 16.0 ± 1.9%), 15 overweight (OW) (body fat: 24.0 ± 1.6%), and 15 obese (OB) (body fat: 31.0 ± 3.0%). All groups completed an incremental cycle exercise to exhaustion in which energy consumption (E, W), ME (%), lipid oxidation rate (LO, %), plasma epinephrine and norepinephrine concentrations were determined consecutively at rest and at three intensity levels corresponding to 50 and 75% of each participant’s maximal heart rate (50%HRmax and 75%HRmax) and peak oxygen consumption (V˙O_2peak). During the incremental cycle exercise test, plasma epinephrine, and norepinephrine responses as well as ME determined at 50%HRmax, 75%HRmax, and at VO_2peak stages were significantly lower in OB compared to NW and OW individuals (ps < 0.01). Multiple linear regressions showed that body weight (ß = -0.64, p < 0.001), energy consumption (ß = -0.24, p < 0.05) and lipid oxidation (ß = 0.69, p < 0.01) were significant predictors of ME at 50%HRmax. However, at 75%HRmax and V˙O_2peak, significant predictors of ME were epinephrine (ß = 0.34, ß = 0.49, respectively, ps = 0.01), norepinephrine (ß = 0.26, ß = 0.60, respectively, ps < 0.05) and power output (ß = 0.62, ß = 0.71, respectively, ps < 0.01). These findings suggest that excess in body weight exerts a negative effect on ME at a low intensity by increasing energy consumption for obese and overweight adolescent boys, while at higher intensities (75%HRmax and VO_2peak) the lower ME could be better explained by the lower power output and catecholamine responses that were attenuated among obese and overweight adolescent boys.

Catecholamines Induce Left Ventricular Subclinical Systolic Dysfunction: A Speckle-Tracking Echocardiography Study

Background: Pheochromocytomas (PHEO) are tumors arising from chromaffin cells from the adrenal medulla, having the ability to produce, metabolize and secrete catecholamines. The overproduction of catecholamines leads by many mechanisms to the impairment in the left ventricle (LV) function, however, endocardial measurement of systolic function did not find any differences between patients with PHEO and essential hypertension (EH). The aim of the study was to investigate whether global longitudinal strain (GLS) derived from speckle-tracking echocardiography can detect catecholamine-induced subclinical impairments in systolic function. Methods: We analyzed 17 patients (10 females and seven males) with PHEO and 18 patients (nine females and nine males) with EH. The groups did not differ in age or in 24-h blood pressure values. Results: The patients with PHEO did not differ in echocardiographic parameters including LV ejection fraction compared to the EH patients (0.69 ± 0.04 vs. 0.71 ± 0.05; NS), nevertheless, in spackle-tracking analysis, the patients with PHEO displayed significantly lower GLS than the EH patients (−14.8 ± 1.5 vs. −17.8 ± 1.7; p < 0.001). Conclusions: Patients with PHEO have a lower magnitude of GLS than the patients with EH, suggesting that catecholamines induce a subclinical decline in LV systolic function.

EPHB6 controls catecholamine biosynthesis by up-regulating tyrosine hydroxylase transcription in adrenal gland chromaffin cells

EPHB6 is a member of the erythropoietin-producing hepatocellular kinase (EPH) family and a receptor tyrosine kinase with a dead kinase domain. It is involved in blood pressure regulation and adrenal gland catecholamine (CAT) secretion, but several facets of EPHB6-mediated CAT regulation are unclear. In this study, using biochemical, quantitative RT-PCR, immunoblotting, and gene microarray assays, we found that EPHB6 up-regulates CAT biosynthesis in adrenal gland chromaffin cells (AGCCs). We observed that epinephrine content is reduced in the AGCCs from male Ephb6-KO mice, caused by decreased expression of tyrosine hydroxylase, the rate-limiting enzyme in CAT biosynthesis. We demonstrate that the signaling pathway from EPHB6 to tyrosine hydroxylase expression in AGCCs involves Rac family small GTPase 1 (RAC1), MAP kinase kinase 7 (MKK7), c-Jun N-terminal kinase (JNK), proto-oncogene c-Jun, activator protein 1 (AP1), and early growth response 1 (EGR1). On the other hand, signaling via extracellular signal-regulated kinase (ERK1/2), p38 mitogen-activated protein kinase, and ELK1, ETS transcription factor (ELK1) was not affected by EPHB6 deletion. We further report that EPHB6's effect on AGCCs was via reverse signaling through ephrin B1 and that EPHB6 acted in concert with the nongenomic effect of testosterone to control CAT biosynthesis. Our findings elucidate the mechanisms by which EPHB6 modulates CAT biosynthesis and identify potential therapeutic targets for diseases, such as hypertension, caused by dysfunctional CAT biosynthesis.

Detection of Plasma Catecholamines in Human Pheochromocytoma and Primary Hypertension Based on Liquid Chromatography Tandem Mass Spectrometry

BACKGROUND

The measurement of plasma catecholamines (CAs) including dopamine (DA), epinephrine (E), and norepinephrine (NE) and their derivatives including metanephrine (MN), normetanephrine (NMN), vanillylmandelic acid (VMA), and homovanillic acid (HVA) has been used in the diagnosis of pheochromocytoma and paraganglioma (PPGL) and primary hypertension (PH) but are typically detected individually when clinical testing. In this study, pre-column derivatization with dansyl chloride (DNS-Cl) combined with an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to simultaneously quantify HVA, VMA, MN, NMN, DA, E, and NE in the plasma from patients with PPGL and PH.

METHODS

Plasma samples were extracted by acetonitrile and derivatized with DNS-Cl, followed by reverse phase separation and triple quadruple detection. Quantification of the CAs and their derivatives in 10 PPGL, 10 PH, and 100 healthy subjects was performed by UPLC-MS/MS analysis.

RESULTS

All the values of detected CAs/derivatives were in the linearity ranges of the fitted curves. The expression levels of the seven CAs in the PPGL and PH patients were significantly higher than the healthy controls, suggesting increased CA production in the former. There were significant differences in plasma NE, NMN, and VMA levels between the PPGL and PH patients, but there was no significant difference in plasma E, MN, DA, and HVA. A discriminant analysis showed that 90% of the final cases were classified correctly based on the detected CAs/derivatives.

CONCLUSIONS

Our results show that the combined detection of the seven CAs/derivatives could be used for the clinical diagnosis of PPGL and PH.

Noradrenaline Acting on Alpha1 Adrenoceptor as well as by Chelating Iron Reduces Oxidative Burden on the Brain: Implications With Rapid Eye Movement Sleep

The noradrenaline (NA) level in the brain is reduced during rapid eye movement sleep (REMS). However, upon REMS deprivation (REMSD) its level is elevated, which induces apoptosis and the degeneration of neurons in the brain. In contrast, isolated studies have reported that NA possesses an anti-oxidant property, while REMSD reduces lipid peroxidation (LP) and reactive oxygen species (ROS). We argued that an optimum level of NA is likely to play a physiologically beneficial role. To resolve the contradiction and for a better understanding of the role of NA in the brain, we estimated LP and ROS levels in synaptosomes prepared from the brains of control and REMS deprived rats with or without in vivo treatment with either α1-adrenoceptor (AR) antagonist, prazosin (PRZ) or α2-AR agonist, clonidine (CLN). REMSD significantly reduced LP and ROS in synaptosomes; while the effect on LP was ameliorated by both PRZ and CLN; ROS was prevented by CLN only. Thereafter, we evaluated in vitro the effects of NA, vitamin E (Vit E), vitamin C (Vit C), and desferrioxamine (DFX, iron chelator) in modulating hydrogen peroxide (H₂O₂)-induced LP and ROS in rat brain synaptosomes, Neuro2a, and C6 cells. We observed that NA prevented ROS generation by chelating iron (inhibiting a Fenton reaction). Also, interestingly, a lower dose of NA protected the neurons and glia, while a higher dose damaged the neurons and glia. These in vitro and in vivo results are complementary and support our contention. Based on the findings, we propose that REMS maintains an optimum level of NA in the brain (an antioxidant compromised organ) to protect the latter from continuous oxidative onslaught.

Mechanisms of Impaired Brown Adipose Tissue Recruitment in Obesity

Brown adipose tissue (BAT) dissipates energy to produce heat. Thus, it has the potential to regulate body temperature by thermogenesis. For the last decade, BAT has been in the spotlight due to its rediscovery in adult humans. This is evidenced by over a hundred clinical trials that are currently registered to target BAT as a therapeutic tool in the treatment of metabolic diseases, such as obesity or diabetes. The goal of most of these trials is to activate the BAT thermogenic program via several approaches such as adrenergic stimulation, natriuretic peptides, retinoids, capsinoids, thyroid hormones, or glucocorticoids. However, the impact of BAT activation on total body energy consumption and the potential effect on weight loss is still limited. Other studies have focused on increasing the mass of thermogenic BAT. This can be relevant in obesity, where the activity and abundance of BAT have been shown to be drastically reduced. The aim of this review is to describe pathological processes associated with obesity that may influence the correct differentiation of BAT, such as catecholamine resistance, inflammation, oxidative stress, and endoplasmic reticulum stress. This will shed light on the thermogenic potential of BAT as a therapeutic approach to target obesity-induced metabolic diseases.

Dopamine Is a Siderophore-Like Iron Chelator That Promotes Salmonella enterica Serovar Typhimurium Virulence in Mice

We have recently shown that the catecholamine dopamine regulates cellular iron homeostasis in macrophages. As iron is an essential nutrient for microbes, and intracellular iron availability affects the growth of intracellular bacteria, we studied whether dopamine administration impacts the course of Salmonella infections. Dopamine was found to promote the growth of Salmonella both in culture and within bone marrow-derived macrophages, which was dependent on increased bacterial iron acquisition. Dopamine administration to mice infected with Salmonella enterica serovar Typhimurium resulted in significantly increased bacterial burdens in liver and spleen, as well as reduced survival. The promotion of bacterial growth by dopamine was independent of the siderophore-binding host peptide lipocalin-2. Rather, dopamine enhancement of iron uptake requires both the histidine sensor kinase QseC and bacterial iron transporters, in particular SitABCD, and may also involve the increased expression of bacterial iron uptake genes. Deletion or pharmacological blockade of QseC reduced but did not abolish the growth-promoting effects of dopamine. Dopamine also modulated systemic iron homeostasis by increasing hepcidin expression and depleting macrophages of the iron exporter ferroportin, which enhanced intracellular bacterial growth. Salmonella lacking all central iron uptake pathways failed to benefit from dopamine treatment. These observations are potentially relevant to critically ill patients, in whom the pharmacological administration of catecholamines to improve circulatory performance may exacerbate the course of infection with siderophilic bacteria.IMPORTANCE Here we show that dopamine increases bacterial iron incorporation and promotes Salmonella Typhimurium growth both in vitro and in vivo These observations suggest the potential hazards of pharmacological catecholamine administration in patients with bacterial sepsis but also suggest that the inhibition of bacterial iron acquisition might provide a useful approach to antimicrobial therapy.

Catecholamines: Knowledge and understanding in the 1960s, now, and in the future

The late 1960s was a heyday for catecholamine research. Technological developments made it feasible to study the regulation of sympathetic neuronal transmission and to map the distribution of noradrenaline and dopamine in the brain. At last, it was possible to explain the mechanism of action of some important drugs that had been used in the clinic for more than a decade (e.g. the first generation of antidepressants) and to contemplate the rational development of new treatments (e.g. l-dihydroxyphenylalanine therapy, to compensate for the dopaminergic neuropathy in Parkinson’s disease, and β₁-adrenoceptor antagonists as antihypertensives). The fact that drug targeting noradrenergic and/or dopaminergic transmission are still the first-line treatments for many psychiatric disorders (e.g. depression, schizophrenia, and attention deficit hyperactivity disorder) is a testament to the importance of these neurotransmitters and the research that has helped us to understand the regulation of their function. This article celebrates some of the highlights of research at that time, pays tribute to some of the subsequent landmark studies, and appraises the options for where it could go next.

COMTVal158Met Genotype Affects Complex Emotion Recognition in Healthy Men and Women

The catechol-o-methyltransferase (COMT) gene has repeatedly been shown to change amygdala activity and amygdala-prefrontal connectivity during face processing. Although the COMT gene appears to induce a negativity bias during the neural processing of faces, it is currently unclear whether a similar negativity bias emerges during the behavioral processing of faces. To address this issue, we investigated differences in complex emotion recognition between participants (n = 181) that had been a priori genotyped for functional polymorphisms of the COMT (Val158Met) and serotonin transporter (5-HTTLPR) gene. We were, thus, able to analyze differences in face processing on basis of participants’ COMT genotype while controlling for participants’ 5-HTTLPR genotype. Variations of participants’ COMT but not 5-HTTLPR genotype accounted for differences in participants’ emotion recognition performance: Met/Met carriers and Met/Val carriers were more accurate in the recognition of negative, but not neutral or positive, expressions than Val/Val carriers. We, therefore, revealed a similar negativity bias during the behavioral processing of faces that has already been demonstrated during the neural processing of faces, indicating that genotype-dependent changes in catecholamine metabolism may affect face processing on the behavioral and neural level.

Dopamine-induced sulfatase and its regulator are required for Salmonella enterica serovar Typhimurium pathogenesis

Catecholamine hormones enhance the virulence of pathogenic bacteria. Studies in the 1980s made intriguing observations that catecholamines were required for induction of sulfatase activity in many enteric pathogens, including Salmonella enterica serovar Typhimurium. In this report, we show that STM3122 and STM3124, part of horizontally acquired Salmonella pathogenesis island 13, encode a catecholamine-induced sulfatase and its regulator, respectively. Induction of sulfatase activity was independent of the well-studied QseBC and QseEF two-component regulatory systems. S. Typhimurium 14028S mutants lacking STM3122 or STM3124 showed reduced virulence in zebrafish. Because catecholamines are inactivated by sulfation in the mammalian gut, S. Typhimurium could utilize CA-induced sulfatase to access free catecholamines for growth and virulence.

Differential Genetic Effect of the Norepinephrine Transporter Promoter Polymorphisms on Attention Problems in Clinical and Non-clinical Samples

Among the monoaminergic modulatory neurotransmitters, norepinephrine is involved in task orienting, hence noradrenergic genetic variants have been studied in connection to attentional processes. The role of this catecholamine system is also highlighted by the selective norepinephrine transporter blocking atomoxetine, which has proved to be effective in the pharmacological treatment of Attention Deficit Hyperactivity Disorder (ADHD). In the present genetic association study three single nucleotide polymorphisms (rs28386840, rs2242446, rs3785143 SNPs) were analyzed from the 5′ region of the norepinephrine transporter (NET, SLC6A2) gene, which have been linked to ADHD previously. Attention problems scores of the mother-rated Child Behavior Checklist (CBCL) were used in separate analyses of 88 preschoolers (59.1% male, 6 years of age) recruited from the general population and 120 child psychiatry patients with ADHD diagnosis (85.8% male, age: 9.8 ± 2.9). The NET SNPs showed associations with attention problems, but the direction was different in the two groups. Regarding the promoter variant rs28386840, which showed the most consistent association, the T-allele-carrier patients with ADHD had lower CBCL attention problems scores compared to patients with AA genotype (p = 0.023), whereas T-allele-carriers in the community sample had more attention problems (p = 0.042). Based on previous reports of lower NE levels in ADHD children and the inverted-U shape effect of NE on cognitive functions, we propose that rs28386840 (-3081) T-allele, which is associated with lower NET expression (and potentially higher synaptic NE level) would support attention processes among ADHD patients (similarly as atomoxetine increases NE levels), whereas it would hinder cortical functions in healthy children.

Control of Leukocyte Trafficking by Stress-Associated Hormones

Leukocyte migration is a crucial process in both homeostatic and inflammatory conditions. The spatiotemporal distribution of immune cells is balanced between processes of cellular mobilization into the bloodstream, their adhesion to vascular beds and trafficking into tissues. Systemic regulation of leukocyte mobility is achieved by different signals including neuronal and hormonal cues, of which the catecholamines and glucocorticoids have been most extensively studied. These hormones are often associated with a stress response, however they regulate immune cell trafficking also in steady state, with effects dependent upon cell type, location, time-of-day, concentration, and duration of signal. Systemic administration of catecholamines, such as the sympathetic neurotransmitters adrenaline and noradrenaline, increases neutrophil numbers in the bloodstream but has different effects on other leukocyte populations. In contrast, local, endogenous sympathetic tone has been shown to be crucial for dynamic daily changes in adhesion molecule expression in the bone marrow and skeletal muscle, acting as a key signal to the endothelium and stromal cells to regulate immune cell trafficking. Conversely, glucocorticoids are often reported as anti-inflammatory, although recent data shows a more complex role, particularly under steady-state conditions. Endogenous changes in circulating glucocorticoid concentration induce redistribution of cells and potentiate inflammatory responses, and in many paradigms glucocorticoid action is strongly influenced by time of day. In this review, we discuss the current knowledge of catecholamine and glucocorticoid regulation of leukocyte migration under homeostatic and stimulated conditions.

Biogenic Amines: Signals Between Commensal Microbiota and Gut Physiology

There is increasing interest in the interactions among the gut microbiota, gut, and brain, which is often referred to as the "microbiota-gut-brain" axis. Biogenic amines including dopamine, norepinephrine, serotonin, and histamines are all generated by commensal gut microorganisms and are suggested to play roles as signaling molecules mediating the function of the "microbiota-gut-brain" axis. In addition, such amines generated in the gut have attracted attention in terms of possible clues into the etiologies of depression, anxiety, and even psychosis. This review covers the latest research related to the potential role of microbe-derived amines such as catecholamine, serotonin, histamine, as well as other trace amines, in modulating not only gut physiology but also brain function of the host. Further attention in this field can offer not only insight into expanding the fundamental roles and impacts of the human microbiome, but also further offer new therapeutic strategies for psychological disorders based on regulating the balance of resident bacteria.

Poor Sleep Quality Associated With High Risk Of Ventricular Tachycardia After Acute Myocardial Infarction

BACKGROUND

Sleep disorders (SDs) are usually associated with an increase in frequency of ventricular tachycardia (VT). However, the relationship between SDs and the prevalence of VT within the first week of acute myocardial infarction (AMI) remains unclear. This study aimed to evaluate their associations and potential mechanisms.

METHODS

This structured questionnaire-based cross-sectional study enrolled 303 patients with AMI from a hospital in northern China. Pittsburgh Sleep Quality Index (PSQI) was used to determine sleep quality of subjects. Heart rate variability (HRV) of patients was investigated by ambulatory electrocardiography recorders. Enzyme-linked immunosorbent assay was used to measure the plasma levels of catecholamine in a subgroup including 80 patients with AMI.

RESULTS

After adjusting to basic cardiovascular characteristics, results of multivariate logistic regression demonstrated that the global PSQI score and its main components were positively associated with VT prevalence in inpatients with AMI. There were significantly different HRV parameters interpreted as autonomic nerve activity in two groups of AMI patients with different sleep quality. In addition, we found the influence of sleep quality on plasma concentrations of adrenaline and norepinephrine in AMI patients.

CONCLUSION

Sleep status was significantly associated with the initiation of VT within the first week of AMI, probably due to the effect of SDs on sympathetic nerve activity. Amelioration of sleep quality and sympathetic hyperactivity may be prospective strategy to curb arrhythmias after AMI.

The melanization road more traveled by: Precursor substrate effects on melanin synthesis in cell-free and fungal cell systems

Natural brown-black eumelanin pigments confer structural coloration in animals and potently block ionizing radiation and antifungal drugs. These functions also make them attractive for bioinspired materials design, including coating materials for drug-delivery vehicles, strengthening agents for adhesive hydrogel materials, and free-radical scavengers for soil remediation. Nonetheless, the molecular determinants of the melanin "developmental road traveled" and the resulting architectural features have remained uncertain because of the insoluble, heterogeneous, and amorphous characteristics of these complex polymeric assemblies. Here, we used 2D solid-state NMR, EPR, and dynamic nuclear polarization spectroscopic techniques, assisted in some instances by the use of isotopically enriched precursors, to address several open questions regarding the molecular structures and associated functions of eumelanin. Our findings uncovered: 1) that the identity of the available catecholamine precursor alters the structure of melanin pigments produced either in Cryptococcus neoformans fungal cells or under cell-free conditions; 2) that the identity of the available precursor alters the scaffold organization and membrane lipid content of melanized fungal cells; 3) that the fungal cells are melanized preferentially by an l-DOPA precursor; and 4) that the macromolecular carbon- and nitrogen-based architecture of cell-free and fungal eumelanins includes indole, pyrrole, indolequinone, and open-chain building blocks that develop depending on reaction time. In conclusion, the availability of catecholamine precursors plays an important role in eumelanin development by affecting the efficacy of pigment formation, the melanin molecular structure, and its underlying scaffold in fungal systems.

Allosteres to regulate neurotransmitter sulfonation

Catecholamine neurotransmitter levels in the synapses of the brain shape human disposition-cognitive flexibility, aggression, depression, and reward seeking-and manipulating these levels is a major objective of the pharmaceutical industry. Certain neurotransmitters are extensively sulfonated and inactivated by human sulfotransferase 1A3 (SULT1A3). To our knowledge, sulfonation as a therapeutic means of regulating transmitter activity has not been explored. Here, we describe the discovery of a SULT1A3 allosteric site that can be used to inhibit the enzyme. The structure of the new site is determined using spin-label-triangulation NMR. The site forms a cleft at the edge of a conserved ∼30-residue active-site cap that must open and close during the catalytic cycle. Allosteres anchor into the site via π-stacking interactions with two residues that sandwich the planar core of the allostere and inhibit the enzyme through cap-stabilizing interactions with substituents attached to the core. Changes in cap free energy were calculated ab initio as a function of core substituents and used to design and synthesize a series of inhibitors intended to progressively stabilize the cap and slow turnover. The inhibitors bound tightly (34 nm to 7.4 μm) and exhibited progressive inhibition. The cap-stabilizing effects of the inhibitors were experimentally determined and agreed remarkably well with the theoretical predictions. These studies establish a reliable heuristic for the design of SULT1A3 allosteric inhibitors and demonstrate that the free-energy changes of a small, dynamic loop that is critical for SULT substrate selection and turnover can be calculated accurately.

Association Between Residential Greenness and Cardiovascular Disease Risk

Background Exposure to green vegetation has been linked to positive health, but the pathophysiological processes affected by exposure to vegetation remain unclear. To study the relationship between greenness and cardiovascular disease, we examined the association between residential greenness and biomarkers of cardiovascular injury and disease risk in susceptible individuals. Methods and Results In this cross-sectional study of 408 individuals recruited from a preventive cardiology clinic, we measured biomarkers of cardiovascular injury and risk in participant blood and urine. We estimated greenness from satellite-derived normalized difference vegetation index ( NDVI ) in zones with radii of 250 m and 1 km surrounding the participants' residences. We used generalized estimating equations to examine associations between greenness and cardiovascular disease biomarkers. We adjusted for residential clustering, demographic, clinical, and environmental variables. In fully adjusted models, contemporaneous NDVI within 250 m of participant residence was inversely associated with urinary levels of epinephrine (-6.9%; 95% confidence interval, -11.5, -2.0/0.1 NDVI ) and F2-isoprostane (-9.0%; 95% confidence interval, -15.1, -2.5/0.1 NDVI ). We found stronger associations between NDVI and urinary epinephrine in women, those not on β-blockers, and those who had not previously experienced a myocardial infarction. Of the 15 subtypes of circulating angiogenic cells examined, 11 were inversely associated (8.0-15.6% decrease/0.1 NDVI ), whereas 2 were positively associated (37.6-45.8% increase/0.1 NDVI ) with contemporaneous NDVI . Conclusions Independent of age, sex, race, smoking status, neighborhood deprivation, statin use, and roadway exposure, residential greenness is associated with lower levels of sympathetic activation, reduced oxidative stress, and higher angiogenic capacity.

Effects of acute and chronic nicotine on catecholamine neurons of the nucleus of the solitary tract

Nicotine is an addictive drug that has broad effects throughout the brain. One site of action is the nucleus of the solitary tract (NTS), where nicotine initiates a stress response and modulates cardiovascular and gastric function through nicotinic acetylcholine receptors (nAChRs). Catecholamine (CA) neurons in the NTS influence stress and gastric and cardiovascular reflexes, making them potential mediators of nicotine's effects; however nicotine's effect on these neurons is unknown. Here, we determined nicotine's actions on NTS-CA neurons by use of patch-clamp techniques in brain slices from transgenic mice expressing enhanced green fluorescent protein driven by the tyrosine hydroxylase promoter (TH-EGFP). Picospritzing nicotine both induced a direct inward current and increased the frequency of spontaneous excitatory postsynaptic currents (sEPSCs) in NTS-CA neurons, effects blocked by nonselective nAChR antagonists TMPH and MLA. The increase in sEPSC frequency was mimicked by nAChRα7 agonist AR-R17779 and blocked by nAChRα7 antagonist MG624. AR-R17779 also increased the firing of TH-EGFP neurons, an effect dependent on glutamate inputs, as it was blocked by the glutamate antagonist NBQX. In contrast, the nicotine-induced current was mimicked by nAChRα4β2 agonist RJR2403 and blocked by nAChRα4β2 antagonist DHβE. RJR2403 also increased the firing rate of TH-EGFP neurons independently of glutamate. Finally, both somatodendritic and sEPSC nicotine responses from NTS-CA neurons were larger in nicotine-dependent mice that had under gone spontaneous nicotine withdrawal. These results demonstrate that 1) nicotine activates NTS-CA neurons both directly, by inducing a direct current, and indirectly, by increasing glutamate inputs, and 2) NTS-CA nicotine responsiveness is altered during nicotine withdrawal.

Risk Stratification on Pheochromocytoma and Paraganglioma from Laboratory and Clinical Medicine

Pheochromocytoma (PCC) and sympathetic paraganglioma (PGL) are rare neuroendocrine tumors characterized by catecholamine production in the adrenal medulla and extra-adrenal paraganglia. PCC and PGL (PPGL) with metastasis was termed malignant PPGL. However, the distinction between “benign” and “malignant” PPGLs has been debated. Currently, all PPGLs are believed to have some metastatic potential and are assigned malignant tumors (ICD-O/3) by the WHO Classification of Endocrine Organs (2017, 4th edition). Therefore, the previous categories benign and malignant PPGL have been eliminated in favor of risk stratification approach. The Grading of Adrenal Pheochromocytoma and Paraganglioma (GAPP) is a tool for risk stratification for predicting metastasis and the prognosis of patients. At least 30% of PPGLs are hereditary, with 20 genes identified and genotype-phenotype correlations clarified. Of these genes, VHL, RET and NF1 have been well investigated and are the primary cause of bilateral PCC. In addition, mutation of succinate dehydrogenase gene subunits SDHB and SDHD are strongly correlated with extra-adrenal location, younger age, multiple tumors, metastasis and poor prognosis. Disease stratification by catecholamine phenotype and molecular profiling correlates with histological grading by GAPP. PPGLs should be understood comprehensively based on clinical, biochemical, molecular and pathological data for patient care. A flow chart for pathological diagnosis is included.

Antihyperalgesic Activity of Atomoxetine on Diabetes-Induced Neuropathic Pain: Contribution of Noradrenergic and Dopaminergic Systems

Atomoxetine is a selective noradrenaline reuptake inhibitor drug. Based on the knowledge that agents increasing monoamine levels in the central nervous system have therapeutic potential for neuropathic pain, it is planned to investigate the possible efficacy of atomoxetine on diabetes-induced hyperalgesia, in this study. Randall-Selitto (mechanical noxious stimuli) and Hargreaves (thermal noxious stimuli) tests were used to evaluate nociceptive perception of rats. Obtained data indicated that streptozotocin-induced diabetes causes significant decreases in the paw withdrawal threshold and paw withdrawal latency values of the animals, respectively. However, atomoxetine administered at 3 mg/kg/day for 7 and 14 days improved these diabetes-induced hyperalgesia responses. Furthermore, antihyperalgesic activity was antagonized with α-methyl-para-tyrosine methyl ester, phentolamine, propranolol, and sulpiride pre-treatments. The same effect was not reversed, however, by SCH 23390. These findings demonstrated, for the first time, that atomoxetine possesses significant antihyperalgesic activity on diabetes-induced neuropathic pain and this effect seems to be mediated by α- and β-adrenergic and D₂/D₃ dopaminergic receptors. Results of this present study seem to offer a new indication for an old drug; atomoxetine, but these preclinical data should first be confirmed with further well-designed clinical trials.

[CME: Pheochromocytoma in the General Practice]

CME: Pheochromocytoma in the General Practice Abstract. Pheochromocytoma are rare tumors, usually symptomatic due to their hormonal activity with excessive catecholamine secretion. Because of their bright spectrum of clinical presentation, they are often undiagnosed. The first diagnostic step is biochemical screening with measurement of free metanephrines in plasma or fractionated metanephrines in 24-hours urine. Knowledge about measurement method used and potential preanalytical factors leading to false results, are necessary for the interpretation. Tumor localisation (imaging) is performed after biochemical evidence of the tumor is present. Laparoscopic surgery is for the majority of cases the primary therapy and curative. Lifelong biochemical follow-up is necessary, with additional tests in case of hereditary tumors.

Myeloid adrenergic signaling via CaMKII forms a feedforward loop of catecholamine biosynthesis

Type 2 immune response has been shown to facilitate cold-induced thermogenesis and browning of white fat. However, whether alternatively activated macrophages produce catecholamine and substantially promote adaptive thermogenesis in adipose tissue remains controversial. Here, we show that tyrosine hydroxylase (TyrH), a rate-limiting enzyme of catecholamine biosynthesis, was expressed and phosphorylated in adipose-resident macrophages. In addition, the plasma level of adrenaline was increased by cold stress in mice, and treatment of macrophages with adrenaline stimulated phosphorylation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and TyrH. Genetic and pharmacological inhibition of CaMKII or PKA signaling diminished adrenaline-induced phosphorylation of TyrH in primary macrophages. Consistently, overexpression of constitutively active CaMKII upregulated basal TyrH phosphorylation, while suppressing the stimulatory effect of adrenaline on TyrH in macrophages. Myeloid-specific disruption of CaMKIIγ suppressed both the cold-induced production of norepinephrine and adipose UCP1 expression in vivo and the stimulatory effect of adrenaline on macrophage-dependent activation of brown adipocytes in vitro. Lack of CaMKII signaling attenuated catecholamine production mediated by cytokines IL-4 and IL-13, key inducers of type 2 immune response in primary macrophages. Taken together, these results suggest a feedforward mechanism of adrenaline in adipose-resident macrophages, and that myeloid CaMKII signaling plays an important role in catecholamine production and subsequent beige fat activation.

Acupuncture Resolves Persistent Pain and Neuroinflammation in a Mouse Model of Chronic Overlapping Pain Conditions

Patients with chronic overlapping pain conditions have decreased levels of catechol-O-methyltransferase (COMT), an enzyme that metabolizes catecholamines. Consistent with clinical syndromes, we previously demonstrated that COMT inhibition in rodents produces persistent pain and heightened immune responses. Here, we sought to determine the efficacy of manual acupuncture in resolving persistent pain and neuroinflammation in the classic inbred C57BL/6 strain and the rapid-wound healing MRL/MpJ strain. Mice received subcutaneous osmotic minipumps to deliver the COMT inhibitor OR486 or vehicle for 13 days. On day 7 after pump implantation, acupuncture was performed at the Zusanli (ST36) point or a non-acupoint for 6 consecutive days. Behavioral responses to mechanical stimuli were measured throughout the experiment. Immunohistochemical analysis of spinal phosphorylated p38 mitogen-activated protein kinase, a marker of inflammation, and glial fibrillary acidic protein, a marker of astrogliosis, was performed on day 13. Results demonstrated that ST36, but not sham, acupuncture resolved mechanical hypersensitivity and reduced OR486-dependent increases in phosphorylated p38 and glial fibrillary acidic protein in both strains. The magnitude of the analgesic response was greater in MRL/MpJ mice. These findings indicate acupuncture as an effective treatment for persistent pain linked to abnormalities in catecholamine signaling and, furthermore, that analgesic efficacy may be influenced by genetic differences. PERSPECTIVE: Chronic overlapping pain conditions remain ineffectively managed by conventional pharmacotherapies. Here, we demonstrate that acupuncture alleviates persistent pain and neuroinflammation linked to heightened catecholaminergic tone. Mice with superior healing capacity exhibit greater analgesic efficacy. Findings indicate acupuncture as an effective treatment for chronic overlapping pain conditions and provide insight into treatment response variability.

Inflammatory Signaling in Hypertension: Regulation of Adrenal Catecholamine Biosynthesis

The immune system is increasingly recognized for its role in the genesis and progression of hypertension. The adrenal gland is a major site that coordinates the stress response via the hypothalamic-pituitary-adrenal axis and the sympathetic-adrenal system. Catecholamines released from the adrenal medulla function in the neuro-hormonal regulation of blood pressure and have a well-established link to hypertension. The immune system has an active role in the progression of hypertension and cytokines are powerful modulators of adrenal cell function. Adrenal medullary cells integrate neural, hormonal, and immune signals. Changes in adrenal cytokines during the progression of hypertension may promote blood pressure elevation by influencing catecholamine biosynthesis. This review highlights the potential interactions of cytokine signaling networks with those of catecholamine biosynthesis within the adrenal, and discusses the role of cytokines in the coordination of blood pressure regulation and the stress response.

The mono(catecholamine) derivatives as iron chelators: synthesis, solution thermodynamic stability and antioxidant properties research

There is a growing interest in the development of new iron chelators as novel promising therapeutic strategies for neurodegenerative disorders. In this article, a series of mono(catecholamine) derivatives, 2,3-bis(hydroxy)-N-(hydroxyacyl)benzamide, containing a pendant hydroxy, have been synthesized and fully characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy and mass spectrum. The thermodynamic stability of the chelators with Fe^III, Mg^II and Zn^II ions was then investigated. The chelators enable formation of (3 : 1) Fe^III complexes with high thermodynamic stability and exhibited improved selectivity to Fe^III ion. Meanwhile, the results of 1,1-diphenyl-2-picryl-hydrazyl assays of mono(catecholamine) derivatives indicated that they all possess excellent antioxidant properties. These results support the hypothesis that the mono(catecholamine) derivatives be used as high-affinity chelator for iron overload situations without depleting essential metal ions, such as Mg^II and Zn^II ions.

Sound-induced monoaminergic turnover in the auditory forebrain depends on endocrine state in a seasonally-breeding songbird

Sensory responses to courtship signals can be altered by reproductive hormones. In seasonally-breeding female songbirds, for example, sound-induced immediate early gene expression in the auditory pathway is selective for male song over behaviourally irrelevant sounds only when plasma estradiol reaches breeding-like levels. This selectivity has been hypothesized to be mediated by release of monoaminergic neuromodulators in the auditory pathway. We previously showed that in oestrogen-primed female white-throated sparrows, exposure to male song induced dopamine and serotonin release in auditory regions. In order to mediate hormone-dependent selectivity, this release must be (1) selective for song and (2) modulated by endocrine state. Therefore, in the current study we addressed both questions by conducting playbacks of song or a control sound to females in a breeding-like or non-breeding endocrine state. We then used high performance liquid chromatography to measure turnover of dopamine, norepinephrine, and serotonin in the auditory midbrain and forebrain. We found that sound-induced turnover of dopamine and serotonin did in fact depend on endocrine state; hearing sound increased turnover in the auditory forebrain only in the birds in a breeding-like endocrine state. Contrary to our expectations, these increases occurred in response to either song or artificial tones; in other words, they were not selective for song. The selectivity of sound-induced monoamine release was thus strikingly different from that of immediate early gene responses described in previous studies. We did, however, find that constitutive monoamine release was altered by endocrine state; whether the birds heard sound or not, turnover of serotonin in the auditory forebrain was higher in a breeding-like state than in a non-breeding endocrine state. Our results suggest that dopaminergic and serotonergic responses to song and other sounds, as well as serotonergic tone in auditory areas, could be seasonally modulated. This article is protected by copyright. All rights reserved.

Clozapine-Induced Cardiovascular Side Effects and Autonomic Dysfunction: A Systematic Review

Background: Clozapine is the antipsychotic of choice for treatment-resistant schizophrenia and has minimal risk for extrapyramidal symptoms. Therapeutic benefits, however, are accompanied by a myriad of cardiometabolic side-effects. The specific reasons for clozapine's high propensity to cause adverse cardiometabolic events remain unknown, but it is believed that autonomic dysfunction may play a role in many of these.

Objective: This systematic review summarizes the literature on autonomic dysfunction and related cardiovascular side effects associated with clozapine treatment.

Method: A search of the EMBASE, MEDLINE, and EBM Cochrane databases was conducted using the search terms antipsychotic agents, antipsychotic drug^*, antipsychotic^*, schizophrenia, schizophren^*, psychos^*, psychotic^*, mental ill^*, mental disorder^*, neuroleptic^*, cardiovascular^*, cardiovascular diseases, clozapine^*, clozaril^*, autonomic^*, sympathetic^*, catecholamine^*, norepinephrine, noradrenaline, epinephrine, adrenaline.

Results: The search yielded 37 studies that were reviewed, of which only 16 studies have used interventions to manage cardiovascular side effects. Side effects reported in the studies include myocarditis, orthostatic hypotension and tachycardia. These were attributed to sympathetic hyperactivity, decreased vagal contribution, blockade of cholinergic and adrenergic receptors, reduced heart rate variability and elevated catecholamines with clozapine use. Autonomic neuropathy was identified by monitoring blood pressure and heart rate changes in response to stimuli and by spectral analysis of heart rate variability. Metoprolol, lorazepam, atenolol, propranolol, amlodipine, vasopressin and norepinephrine infusion were used to treat tachycardia and fluctuations in blood pressure, yet results were limited to case reports.

Conclusion: The results indicate there is a lack of clinical studies investigating autonomic dysfunction and a limited use of interventions to manage cardiovascular side effects associated with clozapine. As there is often no alternative treatment for refractory schizophrenia, the current review highlights the need for better designed studies, use of autonomic tests for prevention of cardiovascular disease and development of novel interventions for clozapine-induced side effects.

Primary functioning hepatic paraganglioma mimicking hepatocellular carcinoma: A case report and literature review

INTRODUCTION

Hepatic paraganglioma (HPGL) originates from the sympathetic nervous tissue in the liver, and is an extremely rare type of the sympathetic paragangliomas. Till now, only 11 HPGL cases have been reported.

CASE PRESENTATION

A 49-year-old woman presented to our hospital with a lesion in the right lobe of the liver, which grew from 2 to 6 cm in 2 years. In addition, she had a 6-year history of diabetes. The patient was initially diagnosed as hepatocellular carcinoma and hepatectomy was performed. Surgical resection of the liver lesion was successful, but the blood pressure rose and fell sharply when the lesion was being removed. The pathological examination of the liver lesion showed that it was HPGL. After the operation, the patient recovered uneventfully. Follow-up examination showed the blood glucose level went back to the normal range in 20 days after the operation, and MRI and I-MIBG scan showed that there was no evidence of recurrence and metastasis in >2 years.

CONCLUSION

By means of reporting this case and reviewing 11 reported cases, we conclude that the incidence of HPGLs is extremely low and the clinical and radiological characteristics of HPGLs are nonspecific; thus, it is hard to diagnose HPGLs correctly. Surgical resection is curative therapy for HPGLs, whereas the removing of HPGLs may cause the releasing of catecholamine, and then lead to hypertension crisis and arrhythmia. Thus, antihypertensive therapy is necessary during the operation. Follow-ups after the operation are important for HPGL patients, for pathological examinations are not sufficient to differ malignant HPGLs from benign ones, and follow-ups are helpful for HPGL patients to find the recurrent foci or metastases timely.