Higher Norepinephrine Research Articles

Noradrenaline dose cutoffs to characterise the severity of cardiovascular failure: Data-based development and external validation.

The vasopressor dose needed is a common measure to assess the severity of cardiovascular failure, but there is no consensus on the ranges of vasopressor doses determining different levels of cardiovascular support. We aimed to identify cutoffs for determining low, intermediate and high doses of noradrenaline (norepinephrine), the primary vasopressor used in intensive care, based on association with hospital mortality. We conducted a binational registry study to determine cutoffs between low, intermediate and high noradrenaline doses. We required the cutoffs to be statistically rational and practical (rounded to the first decimal and easy to remember), and to result in increasing mortality with increasing doses. The highest noradrenaline dose in the first 24 h after intensive care unit (ICU) admission was used. The cutoffs were developed using data from 8079 ICU patients treated in the ICU at Kuopio University Hospital, Finland, between 2013 and 2019. Subsequently, the cutoffs were validated in the eICU database, including 39,007 ICU admissions to 29 ICUs in the United States of America in 2014-2015. The log-rank statistic, with the Contal and O'Quigley method, was used to determine the cutoffs resulting in the most significant split between the noradrenaline dose groups with regard to hospital mortality. The two most prominent peaks in the log-rank statistic corresponded to noradrenaline doses 0.20 and 0.44 μg/kg/min. Accordingly, we determined three dose ranges: low (<0.2 μg/kg/min), intermediate (0.2-0.4 μg/kg/min) and high (>0.4 μg/kg/min). Mortality increased, whereas the number of patients decreased consistently with increasing noradrenaline doses in both cohorts. In the development cohort, hospital mortality was 6.5% in the group without noradrenaline administered and 14.0%, 26.4% and 40.2%, respectively, in the low-dose, intermediate-dose and high-dose groups. Compared to patients who received no noradrenaline, the hazard ratio for in-hospital death was 1.4 for the low-dose group, 4.0 for the intermediate-dose group and 7.5 for the high-dose group in the validation cohort (p < .001). The highest noradrenaline dose is a useful measure for quantifying circulatory failure. Cutoffs 0.2 and 0.4 μg/kg/min seem to be suitable for defining low, intermediate and high doses.

6891 Exclusive Normetanephrine Secreting Pheochromocytoma In A Young Male

Abstract Disclosure: E. Askar: None. H. Moran: None. IntroductionPheochromocytomas and paragangliomas arise from chromaffin cells and produce excessive catecholamines. Hypertension is their primary clinical symptom. they differ in their catecholamine secretory phenotype; paragangliomas typically secrete norepinephrine, while pheochromocytomas typically secrete epinephrine. Here, we present a case 21-year-old male with pheochromocytoma with elevated norepinephrine but normal epinephrine levels.Case presentationA 21 -year-old male with no past medical history presented with episodes of palpitations, sweating, and elevated blood pressure. He also reported abdominal pain. On admission, his blood pressure was 143/92 mmHg, pulse was 71/min, respiration was 16/min, and oxygen saturation was 100% in room air. The rest of physical exam was not significant. His electrolyte panel was normal. Computed tomography (CT) abdomen and pelvis with contrast was performed and showed a right adrenal mass measuring 4.9 x 4.0 x 6.5 cm which is predominantly hypoattenuating (approximately 30 Hounsfield units) with thick nodular rim of enhancement. Hormonal workup showed normal serum testosterone, DHEA-S, AM cortisol, ACTH, aldosterone, plasma metanephrine, and urine metanephrine, but profoundly high plasma normetanephrine 3641.6 (0.0-210.1) pg/mL. His 24-hour urinary normetanephrine was elevated at 14874 (80-440) ug/24hr, confirming a pheochromocytoma. The high norepinephrine level in the setting of normal epinephrine raised suspicion for Von Hippel Lindau (VHL). He was started on alpha and beta blockage and had laparoscopic removal of the right adrenal gland. The pathology report confirmed the diagnosis of pheochromocytoma confined to right adrenal. The patient was then referred for genetic testing. Conclusion: Pheochromocytoma can be a part of familial disorders, although being sporadic in nature most of the time. As demonstrated in our case, the hallmark of pheochromocytoma associated with VHL is nearly exclusive normetanephrine secretion and a high ratio of normetanephrine to metanephrine. Confirmation and testing of genes aid in proper monitoring and follow-up. The preferred course of treatment is radical resection. Presentation: 6/2/2024

Lifetime chronic stress Exposures, stress Hormones, and biological Aging: Results from the midlife in the United States (MIDUS) study

Psychosocial stress and adversity have been linked to accelerated aging and increased risk for age-related diseases. Animal and in vitro studies have shown that exposure to stress hormones (catecholamines, glucocorticoids) can impact biological aging processes such as DNA damage and cellular senescence, suggesting they play a key role in links between stress and aging; however, these associations have not been well investigated in humans. We examined cross-sectional associations between chronic stress exposures, stress hormones, and biological aging markers in midlife adults and whether stress hormones mediated associations between stress and aging. Participants were 531 adults aged 26–78 years (Mage = 53.9, 50.1 % female) in the nationally representative Midlife in the United States Refresher cohort. They reported chronic stress exposures in childhood and adulthood (Stressful Life Event Inventory) and provided 12-hour urine samples used to assess norepinephrine, epinephrine, and cortisol. RNA sequencing of peripheral blood mononuclear cells derived aging biomarkers: the DNA damage response (DDR; 30-gene composite), cellular senescence signal p16INK4a (CDKN2A), and the pro-inflammatory senescence-associated secretory phenotype (SASP; 57-gene composite). Regression models adjusting for age, sex, race/ethnicity, BMI, smoking status, alcohol use, and medications revealed that more childhood exposures were associated with higher norepinephrine (β = 0.09, p = 0.04), independent from adult exposures. Higher norepinephrine was associated with elevated DDR expression (β = 0.17, p < 0.001). Higher norepinephrine (β = 0.14, p = 0.003) and epinephrine (β = 0.10, p = 0.02) were both associated with elevated SASP expression. Statistical mediation analyses implicated elevated norepinephrine as a plausible mediator of associations between childhood exposures and both DDR (unstandardized b = 0.005, 95 % CI [0.0002, 0.011]) and SASP (b = 0.002, 95 % CI [0.0001, 0.05]). Findings provide preliminary evidence in humans that stress hormones may impact key biological aging processes and may be a mechanism linking chronic stress exposures in childhood to accelerated aging later in life.

Norepinephrine Reuptake Inhibition, an Emergent Treatment for Neurogenic Orthostatic Hypotension.

The NET (norepinephrine transporter) is situated in the prejunctional plasma membrane of noradrenergic neurons. It is responsible for >90% of the norepinephrine uptake that is released in the autonomic neuroeffector junction. Inhibitors of this cell membrane transporter, known as norepinephrine reuptake inhibitors (NRIs), are commercially available for the treatment of depression and attention deficit hyperactivity disorder. These agents increase norepinephrine levels, potentiating its action in preganglionic and postganglionic adrenergic neurons, the latter through activation of α-1 adrenoreceptors. Previous studies found that patients with neurogenic orthostatic hypotension can improve standing blood pressure and reduce symptoms of neurogenic orthostatic hypotension after a single administration of the selective NRI atomoxetine. This effect was primarily observed in patients with impaired central autonomic pathways with otherwise normal postganglionic sympathetic fibers, known as multiple system atrophy. Likewise, patients with normal or high norepinephrine levels may benefit from NRIs. The long-term efficacy of NRIs for the treatment of neurogenic orthostatic hypotension-related symptoms is currently under investigation. In summary, an in-depth understanding of the pathophysiology of neurogenic orthostatic hypotension resulted in the discovery of a new therapeutic pathway targeted by NRI.

The emotion paradox in the aging body and brain.

With age, parasympathetic activity decreases, while sympathetic activity increases. Thus, the typical older adult has low heart rate variability (HRV) and high noradrenaline levels. Younger adults with this physiological profile tend to be unhappy and stressed. Yet, with age, emotional experience tends to improve. Why does older adults' emotional well-being not suffer as their HRV decreases? To address this apparent paradox, I present the autonomic compensation model. In this model, failing organs, the initial phases of Alzheimer's pathology, and other age-related diseases trigger noradrenergic hyperactivity. To compensate, older brains increase autonomic regulatory activity in the pregenual prefrontal cortex (PFC). Age-related declines in nerve conduction reduce the ability of the pregenual PFC to reduce hyperactive noradrenergic activity and increase peripheral HRV. But these pregenual PFC autonomic compensation efforts have a significant impact in the brain, where they bias processing in favor of stimuli that tend to increase parasympathetic activity (e.g., stimuli that increase feelings of safety) and against stimuli that tend to increase sympathetic activity (e.g., threatening stimuli). In summary, the autonomic compensation model posits that age-related chronic sympathetic/noradrenergic hyperactivity stimulates regulatory attempts that have the side effect of enhancing emotional well-being.

Decreased levels of hydrogen sulfide in the hypothalamic paraventricular nucleus contribute to sympathetic hyperactivity induced by cerebral infarction.

Paroxysmal sympathetic hyperactivity (PSH) is a common clinical feature secondary to ischemic stroke (IS), but its mechanism is poorly understood. We aimed to investigate the role of H2S in the pathogenesis of PSH. IS patients were divided into malignant (MCI) and non-malignant cerebral infarction (NMCI) group. IS in rats was induced by the right middle cerebral artery occlusion (MCAO). H2S donor (NaHS) or inhibitor (aminooxy-acetic acid, AOAA) were microinjected into the hypothalamic paraventricular nucleus (PVN). Compared with the NMCI group, patients in the MCI group showed PSH, including tachycardia, hypertension, and more plasma norepinephrine (NE) that was positively correlated with levels of creatine kinase, glutamate transaminase, and creatinine respectively. The 1-year survival rate of patients with high plasma NE levels was lower. The hypothalamus of rats with MCAO showed increased activity, especially in the PVN region. The levels of H2S in PVN of the rats with MCAO were reduced, while the blood pressure and renal sympathetic discharge were increased, which could be ameliorated by NaHS and exacerbated by AOAA. NaHS completely reduced the disulfide bond of NMDAR1 in PC12 cells. The inhibition of NMDAR by MK-801 microinjected in PVN of rats with MCAO also could lower blood pressure and renal sympathetic discharge. In conclusion, PSH may be associated with disease progression and survival in patients with IS. Decreased levels of H2S in PVN were involved in regulating sympathetic efferent activity after cerebral infarction. Our results might provide a new strategy and target for the prevention and treatment of PSH.

Maternal and neonatal cortisol and catecholamines throughout vaginal eutocia and C-section in dogs

Increased fetal cortisol is associated with catecholamine release, a primary factor for neonatal adaptive responses. However, relationship between canine peripartum cortisol and catecholamine is unknown. We aimed to compare serum adrenaline, noradrenaline and cortisol during peripartum in bitches and neonates of distinct obstetric conditions and to assess amniotic fluid cortisol concentration. Twenty females and maximum of three puppies per litter were allocated into Vaginal Eutocia (10 females; 17 neonates) and Elective C-section (10 females; 20 neonates) groups. Amniotic fluid was collected at delivery for cortisol concentration. Maternal and neonatal blood were collected prepartum, intrapartum, postpartum and 1h postpartum, and at birth, 30 and 60min, 12hs and 24hs, respectively, for cortisol, adrenaline and noradrenaline assessment. C-section determined higher noradrenaline throughout delivery and cortisol concentration from intrapartum through 1h postpartum, compared to vaginal birth. C-section maternal cortisol showed progressive increase from intrapartum onwards, while neonatal cortisol remained unchanged. No difference of maternal cortisol concentration occurred along whelping, whereas a significant decrease was verified for vaginal delivery puppies from birth until the 12hs. Puppies delivered vaginally had higher cortisol concentration at birth and 30min, compared to c-section puppies. There was a higher concentration of amniotic fluid cortisol in vaginal eutocia. In conclusion, c-section induces higher maternal stress during and after surgery, whilst vaginal delivery is a more neonatal physiologically stressful condition, contributing to better adaptation during transition.

Анализ содержания катехоламинов и параметров липидного обмена у аборигенного и местного европеоидного населения Арктической зоны Российской Федерации

The study of fat metabolism and the levels of sympathoadrenal hormones in the indigenous population of the Arctic presently changing their lifestyle from nomadic to sedentary is undoubtedly of practical interest. The purpose of this article was to conduct a comparative analysis of the content of catecholamines, triglycerides and saturated fatty acids in the inhabitants of the Arctic zone of the Russian Federation, depending on their lifestyle (nomadic indigenous people, sedentary indigenous people, and local Russian population), age and sex. Materials and methods. The study involved 472 subjects: men and women of the first (men: 22–35 years old; women: 21–35 years old) and second (men: 36–60 years old; women: 36–55 years old) periods of adulthood, leading different lifestyles. The following were determined in the blood serum: triglyceride concentrations using the enzymatic method; level of saturated fatty acids (ƩSFA) using gas-liquid chromatography, followed by а calculation of the content of short-, medium- and long-chain saturated fatty acids (ƩSCFA, ƩMCFA, ƩLCFA). Urine levels of adrenaline and noradrenaline were determined by means of fluorimetry. Results. Regardless of their lifestyle, adult subjects, primarily women, showed high adrenaline values, low triglyceride concentrations and elevated ƩSFA. Correlation analysis established a negative association of adrenaline with ƩLCFA and ƩSFA in sedentary indigenous women aged 21–35 years and with ƩMCFA in those aged 36–55 years. In local Russian women aged 36–55 years, on the contrary, a positive association of noradrenaline with ƩSCFA, ƩMCFA, ƩLCFA and ƩSFA was found. No statistically significant correlations were identified in nomadic indigenous women. Unlike women, men had a correlation between adrenaline content and ƩMCFA only among local Russians: negative in 22–35-year-olds and positive in 36–60-year-olds with high noradrenaline levels. On the one hand, low triglyceride values and elevated ƩSFA among residents of the Arctic zone of the Russian Federation maintain the energy homeostasis of the body. On the other hand, they lead to overweight and obesity, which increases the risk of new-onset metabolic dysfunction-associated diseases, especially in women.

High Norepinephrine State Induces Growth of Colorectal Cancer Cells via ADP-Ribosyltransferase 1 in Type 2 Diabetes Mellitus.

Patients with type 2 diabetes mellitus have a higher susceptibility for colorectal cancer and poorer prognosis, but the mechanism is still unknown. Here, we investigated the effect of ADP-ribosyltransferase 1 (ART1) on the growth of colorectal cancer in an animal model of diabetes with high norepinephrine status, as well as the potential mechanism. We evaluated the size and weight of transplanted CT26 cell tumors with different ART1 expression levels in a mouse model of diabetes, as well as the survival time. CCK8 and flow cytometry were used to evaluate the growth of CT26 cells in vitro. Western blot was performed to analyze differentially expressed proteins in the ART1-modulated pathway. High levels of norepinephrine and ART1 favored the proliferation of CT26 cells in vitro and in vivo. Moreover, inhibition of norepinephrine-dependent proliferation was observed in ART1-silenced CT26 cells compared to those with normal ART1 expression. Following reduction of the serum norepinephrine level by surgery, the size and weight of transplanted CT26 cell tumors was significantly reduced compared to non-operated and sham-operated mice. Furthermore, the expression of ART1, mTOR, STAT3, and p-AKT protein in the tumor tissue of diabetic mice was higher than in non-diabetic mice. Following reduction of the norepinephrine level by renal denervation (RD), expression of the proliferation-related proteins mTOR, STAT3, p-AKT protein decreased, but no change was seen for ART1 expression. At the same concentration of norepinephrine, ART1 induced the expression of p-AKT, mTOR, STAT3, CyclinD1 and c-myc in CT26 cells in vitro. We conclude that faster growth of colorectal cancer in high norepinephrine conditions requires the expression of ART1, and that high ART1 expression may be a novel target for the treatment of diabetes-associated colorectal cancer.

The role of sociability in social instability stress: Behavioral, neuroendocrine and monoaminergic effects

Extensive literature has reported a link between social stress and mental health. In this complex relationship, individual strategies for coping with social stress are thought to have a possible modulating effect, with sociability being a key factor. Despite the higher incidence of affective disorders in females and sex-related neurochemical differences, female populations have been understudied. The aim of the present study was, therefore, to analyze the behavioral, neuroendocrine, and neurochemical effects of stress in female OF1 mice, paying special attention to social connectedness (female mice with high vs low sociability). To this end, subjects were exposed to the Chronic Social Instability Stress (CSIS) model for four weeks. Although female mice exposed to CSIS had increased arousal, there was no evidence of depressive-like behavior. Neither did exposure to CSIS affect corticosterone levels, although it did increase the MR/GR ratio by decreasing GR expression. Female mice exposed to CSIS had higher noradrenaline and dopamine levels in the hippocampus and striatum respectively, with a lower monoaminergic turnover, resulting in an increased arousal. CSIS increased serotonin levels in both the hippocampus and striatum. Similarly, CSIS was found to reduce kynurenic acid, 3-HK, and IDO and iNOS enzyme levels in the hippocampus. Interestingly, the observed decrease in IDO synthesis and the increased serotonin and dopamine levels in the striatum were only found in subjects with high sociability. These highly sociable female mice also had significantly lower levels of noradrenaline in the striatum after CSIS application. Overall, our model has produced neuroendocrine and neurochemical but not behavioral changes, so it has not allowed us to study sociability in depth. Therefore, a model that induces both molecular and behavioral phenotypes should be applied to determine the role of sociability.

Norepinephrine dose, lactate or heart rate: what impacts prognosis in sepsis and septic shock? Results from a prospective, monocentric registry

Objective The study comprehensively investigates the prognostic value of norepinephrine (NE) dose, lactate and heart rate in patients with sepsis and septic shock. Limited data regarding the prognostic value of NE dose, lactate and heart rate in patients meeting the sepsis-3 criteria is available. Methods Consecutive patients with sepsis and septic shock from 2019 to 2021 were included. The prognostic value of NE dose, lactate and heart rate was tested for 30-day all-cause mortality. Statistical analyses included univariable t-tests, Spearman’s correlations, C-statistics, Kaplan–Meier analyses, as well as one-factorial repeated measures analysis of variance (ANOVA) and Cox proportional regression analyses. Results 339 patients with sepsis or septic shock were included. With an area under the curve (AUC) of up to 0.638 and 0.685, NE dose and lactate revealed moderate prognostic accuracy for 30-day all-cause mortality, whereas heart rate was not associated with prognosis. Very high NE doses (i.e. > 1.0 mcg/kg/min) (HR = 2.938; 95% CI 1.933 − 4.464; p = .001) and lactate levels (i.e. ≥ 4 mmol/l) (HR = 2.963; 95% CI 2.095 − 4.191; p = .001) on admission were associated with highest risk of death. Finally, increasing NE doses and lactate levels from day 1 to 3 indicated increased risk of death, which was consistent after multivariable adjustment. Conclusion Both very high NE doses and lactate levels – but not heart rate – were associated with increased risk of 30-d all-cause mortality in patients with sepsis and septic shock.

Refractory septic shock and alternative wordings: A systematic review of literature

BackgroundWe reviewed the different studies using the terms “refractory septic shock” and/or “catecholamine resistance” and/or “high dose norepinephrine” so as to highlight the heterogeneity of the definitions used by authors addressing such concepts. MethodA systematic review was conducted assessing the papers reporting data on refractory septic shock. We used keywords as exact phrases and subject headings according to database syntax. ResultsOf 276 papers initially reviewed, we included 8 studies – 3 randomized controlled trials, 3 prospective studies and 2 retrospective studies, representing a total of 562 patients with septic shock. Catecholamine resistance was generally defined as “a decreased vascular responsiveness to catecholamine independently of the administered norepinephrine dose”. Refractory septic shock was broadly defined as “a clinical condition characterized by persistent hyperdynamic shock even though adequate fluid resuscitation (individualized doses) and high doses of norepinephrine (≥ 1 μg/kg/min)”. Reported “high doses” of norepinephrine were often ≥1 μg/kg/min. However, wide variability was found throughout the literature on the use of these terms. DiscussionMarked inconsistencies were identified in the usage of the terms for refractory septic shock. There is a pressing need to determine consensus definitions so as to establish a common language in the medical literature and to harmonize future studies.

Upregulations of α1 adrenergic receptors and noradrenaline synthases in the medial prefrontal cortex are associated with emotional and cognitive dysregulation induced by post-weaning social isolation in male rats

Early-life social isolation induces emotional and cognitive dysregulation, such as increased aggression and anxiety, and decreases neuron excitability in the medial prefrontal cortex (mPFC). The noradrenergic system in the mPFC regulates emotion and cognitive function via α1 or α2A adrenergic receptors, depending on noradrenaline levels. However, social isolation-induced changes in the mPFC noradrenergic system have not been reported. Here, male Wistar rats received post-weaning social isolation for nine consecutive weeks and were administered behavioral tests (novel object recognition, elevated plus maze, aggression, and forced swimming, sequentially). Protein expression levels in the mPFC noradrenergic system (α1 and α2A adrenergic receptors, tyrosine hydroxylase, and dopamine-β-hydroxylase used as indices of noradrenaline synthesis and release) were examined through western blotting. Social isolation caused cognitive dysfunction, anxiety-like behavior, and aggression, but not behavioral despair. Socially-isolated rats exhibited increased protein levels of the α1 adrenergic receptor, tyrosine hydroxylase, and dopamine-β-hydroxylase in the mPFC; there was no significant difference between the groups in the α2A adrenergic receptor expression levels. Preferential activation of the α1 adrenergic receptor caused by high noradrenaline concentration in the mPFC may be involved in social isolation-induced emotional and cognitive regulation impairments. Targeting the α1 adrenergic receptor signaling pathway is a potential therapeutic strategy for psychiatric disorders with symptomatic features such as emotional and cognitive dysregulation.

Active vs passive novelty-related strategies: Sex differences in exploratory behaviour and monoaminergic systems

Sex differences are apparent in numerous behavioural characteristics. In order to compare and characterise male and female variability of exploratory behaviour, 365 male and 401 female rats were assessed in a task where a bimodal response distribution had previously been established in males. Female rats had significantly higher exploratory activity, and presented normal distribution of the behaviour, very differently from the bimodal distribution of males. No major effect of litter or oestrous cycle was detected. Several differences between male and female rats were found in monoamine metabolism measured ex vivo. Male rats had lower levels of dopamine (DA) in frontal cortex, and higher levels of 3,4-dihydroxyphenylacetic acid (DOPAC) in raphe area; higher levels of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in dorsal striatum but lower levels of 5-HT and 5-HIAA in locus coeruleus area, 5-HIAA levels were also lower in hippocampus as compared to females. Males had higher noradrenaline (NA) levels in hippocampus and lower normetanephrine (NMN) levels in striatum, in both brain regions male animals had lower NMN/NA ratio. No sex difference was found in accumbens. The only brain region with an interaction between sex and the expression of exploratory activity was raphe: Here 5-HT levels were lower, and DOPAC levels and DOPAC/DA and 5-HIAA/5-HT ratios higher in low exploring male but not female rats. Conclusively, female rats not only display higher levels of exploration but the population distribution of this behaviour is distinct; this may be related to differences in the monoaminergic systems between female and male animals.

PS-B02-5: NICORANDIL SUPPRESSES ISCHEMIA-INDUCED CARDIAC NOREPINEPHRINE ENHANCEMENT AND VENTRICULAR ARRHYTHMIAS IN PRESSURE OVERLOAD-INDUCED HYPERTROPHIC HEARTS.

Objective: Ventricular arrhythmias are a common cause of sudden death in acute myocardial infarction (MI) and hypertension is a major risk factor of MI. Nicorandil, an ATP sensitive potassium channel (KATP) opener, is usually used in the treatment of acute MI. KATP expresses in nerve terminals as well as cardiomyocytes and KATP in nerve terminals regulates norepinephrine release. The effects of nicorandil on ischemic myocyte are fully defined. On the other hand, the roles of nicorandil on ischemic norepinephrine release in hypertrophic cardiac tissue has remained unexplored. We examined whether nicorandil suppressed interstitial norepinephrine level and ventricular arrhythmia during acute ischemia in chronic pressure overload-induced hypertrophic hearts. Design and Methods: Rats were divided into two groups: abdominal aortic constriction (AAC) group and sham-operated (Sham) group. Four weeks after constriction, cardiac geometry and function were examined using echocardiography and hemodynamic measurements, and cardiac tissues were stained with hematoxylin and eosin and Sirius Red for histological examinations. In other rats, 4 weeks after constriction myocardial ischemia was induced by the left anterior descending artery occlusion for 100 minutes in the presence or absence of intravenous infusion of nicorandil. Cardiac interstitial norepinephrine concentration in ischemic region was measured using the microdialysis method. Ventricular arrhythmias were monitered by ECG during whole ischemic period. Results: Four weeks after constriction, remarkable left ventricular wall thickening and diastolic dysfunction were observed in AAC group. In histological examination, remarkable myocyte hypertrophy and interstitial fibrosis were observed in AAC group. Before ischemia, ventricular arrhythmia was not found in both groups. Number of ventricular arrhythmias, including ventricular tachycardia and ventricular fibrillation, was increased in early ischemic period (−20 min) in both groups, and was grater in AAC group. Before ischemia, interstitial norepinephrine concentration in cardiac tissue was higher level in AAC group than in Sham group, and ischemia increased norepinephrine concentration in both groups. Nicorandil administration in ischemic period significantly suppressed the number of ventricular arrhythmias and abolished the ventricular tachycardia and fibrillation without hemodynamic alterations in hypertrophic hearts. Nicorandil also attenuated epinephrine enhancement in acute ischemic period in hypertrophic hearts. Conclusion: Ischemia-induced ventricular arrhythmias were more frequent and severe in hypertrophic hearts and associated with high interstitial norepinephrine concentration. Nicorandil suppressed ischemia-induced interstitial norepinephrine release by neuronal KATP opening, which attenuated ventricular arrhythmias in pressure overload-induced hypertrophic hearts.

Alpha1B-adreneroceptor is involved in norepinephrine-induced pulmonary artery smooth muscle cell proliferation via p38 signaling

The higher norepinephrine (NE) concentration induced by sympathetic nerve hyperactivation participated in pulmonary artery smooth muscle cells (PASMCs) over-proliferation and led to pulmonary vascular remodeling (PVR), which played an important role in pulmonary artery hypertension (PAH). However, the underlying mechanism by which NE induced PASMCs proliferation had not been fully elucidated. In the present study, we found that prazosin, the inhibitor of α1-AR, reversed hypoxia-induced changes in pulmonary circulatory function which were analyzed by echocardiography to measure pulmonary artery acceleration time (PAT) and pulmonary arterial velocity time integral (PAVTI) and right heart catheterization to test right ventricular systolic pressure (RVSP), respectively. Western blotting analysis showed that the expression of alpha1B-adreneroceptor (α1B-AR) increased under hypoxic conditions both in vivo and in vitro. Antagonism of α1B-AR by chloroethylclonidine dihydrochloride (CEC) reversed the NE-induced proliferation in rat PASMCs, which was confirmed by applying Western blotting to test proliferating cell nuclear antigen (PCNA) expression, CCK8 assay to test cell viability, scratch-wounding cellular migration assay to show cell proliferative capacity and immunofluorescence to show Ki67 expression. Furthermore, we revealed that antagonism of α1B-AR alleviated NE-induced acceleration of cell-cycle progression by Western blotting to detect cell-cycle-related protein. In addition, Western blotting results showed that antagonism of α1B-AR reversed NE-promoted phosphorylation of p38 (p-p38) under hypoxia. SB202190, an inhibitor of p38, reversed NE-induced proliferation and acceleration of cell-cycle progression of PASMCs. These results suggested that α1B-AR was involved in NE-induced PASMCs proliferation via p38 signaling pathway, which might be downstream of α1B-AR.

When COVID-19 prophylaxis leads to hydroxychloroquine poisoning

Hydroxychloroquine overdose was a relatively uncommon event prior to the COVID-19 pandemic. However, due to the massive increase in prescriptions, coupled with the search for possibly effective treatment COVID-19 infection, these overdoses have become more frequent. The management of severe hydroxychloroquine overdose does not have any well-established protocols. This report highlights the clinical course and successful management of a life-threatening hydroxychloroquine overdose. An 80-year-old man was admitted to the ICU in shock after a potentially lethal ingestion of hydroxychloroquine for COVID-19 prophylaxis in a COVID-19 negative patient. Treatments included sodium bicarbonate infusion, high dose diazepam, norepinephrine and epinephrine, and continuous electrolyte repletion. After 5 days in the intensive care unit, the patient recovered and was discharged home. In conclusion, hydroxychloroquine overdose can result in life-threatening rapid decompensation requiring gastric decontamination, alkalization, high dose diazepam, hemodynamic support, and frequent electrolyte replacement.

Sustained chemogenetic activation of locus coeruleus norepinephrine neurons promotes dopaminergic neuron survival in synucleinopathy.

Dopaminergic neuron degeneration in the midbrain plays a pivotal role in motor symptoms associated with Parkinson’s disease. However, non-motor symptoms of Parkinson’s disease and post-mortem histopathology confirm dysfunction in other brain areas, including the locus coeruleus and its associated neurotransmitter norepinephrine. Here, we investigate the role of central norepinephrine-producing neurons in Parkinson’s disease by chronically stimulating catecholaminergic neurons in the locus coeruleus using chemogenetic manipulation. We show that norepinephrine neurons send complex axonal projections to the dopaminergic neurons in the substantia nigra, confirming physical communication between these regions. Furthermore, we demonstrate that increased activity of norepinephrine neurons is protective against dopaminergic neuronal depletion in human α-syn A53T missense mutation over-expressing mice and prevents motor dysfunction in these mice. Remarkably, elevated norepinephrine neurons action fails to alleviate α-synuclein aggregation and microgliosis in the substantia nigra suggesting the presence of an alternate neuroprotective mechanism. The beneficial effects of high norepinephrine neuron activity might be attributed to the action of norepinephrine on dopaminergic neurons, as recombinant norepinephrine treatment increased primary dopaminergic neuron cultures survival and neurite sprouting. Collectively, our results suggest a neuroprotective mechanism where noradrenergic neurons activity preserves the integrity of dopaminergic neurons, which prevents synucleinopathy-dependent loss of these cells.

Hyperspectral Imaging for the Evaluation of Microcirculatory Tissue Oxygenation and Perfusion Quality in Haemorrhagic Shock: A Porcine Study.

Background: The ultimate goal of haemodynamic therapy is to improve microcirculatory tissue and organ perfusion. Hyperspectral imaging (HSI) has the potential to enable noninvasive microcirculatory monitoring at bedside. Methods: HSI (Tivita® Tissue System) measurements of tissue oxygenation, haemoglobin, and water content in the skin (ear) and kidney were evaluated in a double-hit porcine model of major abdominal surgery and haemorrhagic shock. Animals of the control group (n = 7) did not receive any resuscitation regime. The interventional groups were treated exclusively with either crystalloid (n = 8) or continuous norepinephrine infusion (n = 7). Results: Haemorrhagic shock led to a drop in tissue oxygenation parameters in all groups. These correlated with established indirect markers of tissue oxygenation. Fluid therapy restored tissue oxygenation parameters. Skin and kidney measurements correlated well. High dose norepinephrine therapy deteriorated tissue oxygenation. Tissue water content increased both in the skin and the kidney in response to fluid therapy. Conclusions: HSI detected dynamic changes in tissue oxygenation and perfusion quality during shock and was able to indicate resuscitation effectivity. The observed correlation between HSI skin and kidney measurements may offer an estimation of organ oxygenation impairment from skin monitoring. HSI microcirculatory monitoring could open up new opportunities for the guidance of haemodynamic management.

PREDICTION OF BIOLOGICAL ACTIVITIES OF A. SQUAMOSA BIOACTIVE COMPOUNDS BY-SILICO DESIGN

Annona squamosa L. belongs to the Annonaceae family and is one of the basic dietary plants with edible fruits and is called "custard apple. The aim of our study was to carry out to PASS Predication investigate potential Prediction of Activity Spectra for phytoconstituents from Alpinia calcarata namely Acetogenins, Isoquinoline, Quercetin 3 Oglucoside, phenanthrene and Anoreticuin towards many deasease. Server based in silico pass prediction of the compounds was performed. Selected phytochemicals were also analyzed for ADME/T properties using the ADMET protocol. Among a wide range of predicting Acetogenins, Isoquinoline, Quercetin-3-O-glucoside, Phenanthrene and Annoreticuin are effective against fungal pathogens of CYP2H substrates and inhibitors of membrane permeability (0.66 less than Pa greater than 0.90) activity and this can be supported by ADMET properties of these compounds. So Acetogenins have good absorbability, especially in human intestinal absorption. Isoquinoline and norepinephrine are kinase inhibitors, while the high molecular weight compounds phenanthrene and norepinephrine have a low GI absorption distribution across the blood-brain barrier (BBB) and central nervous system. Also the results from ADME/T properties ensured the compounds safe for human.