Sympathectomy Effects on Intra-Abdominal Organ Catecholamine Levels in a Streptozotocin-Induced Diabetic Rat Model

Diabetes mellitus (DM) is a metabolic disorder whose prevalence has continuously increased worldwide and is associated with dysfunction of the autonomic nervous system and, in particular, that of the sympathetic nervous system (SNS). The objective of this study was to analyze the interaction of DM and the SNS, building a model of sympathectomized diabetic rats to determine alterations in the content of CA (catecholamines) in different intra-abdominal organs. Sympathectomy was conducted with guanethidine (GNT). Additionally, DM was induced with STZ (Streptozotocin). Treatment with GNT decreased norepinephrine (NE) content in all analyzed tissues, with significant differences found in the paraganglia, liver, pancreas, duodenum, and heart compared to the control group. With respect to epinephrine (E), which was only found in the liver, pancreas, and heart, presenting significant differences (p < 0.05) in the heart, a decrease in its concentration was observed for all of the experimental groups with respect to the control. The decrease in dopamine (DA) content due to the GNT−STZ treatment was 30.1% in the heart with respect to the diabetic (STZ) group. The amount of CA in the adrenal medulla indicates the effect of sympathectomy on the GNT group where there was a significant reduction (p < 0.05) of DA. These findings suggest that the elimination of the sympathetic nervous system in diabetic organisms contributed to a decrease in blood glucose; likewise, an alteration in the levels of CA was observed in the different selected organs, possibly attributed to the severity, duration, and pathogenesis of the complications of acute and chronic DM.

Anxiolytic and Antioxidant Effect of Phytoecdysteroids and Polyphenols from Chenopodium quinoa on an In Vivo Restraint Stress Model

The variety of stressful conditions in daily human activity requires nutritional support with safe, specialized food products containing functional food ingredients (FFIs) enriched with biologically active plant substances with proven adaptogenic properties. In this in vivo study, by evaluating a set of physiological parameters and biochemical markers, we investigated the effectiveness of the developed FFIs from Chenopodium quinoa grains in stress conditions induced by daily episodes of immobilization for 36 days. The results of the evaluation of the anxiety-like functions, locomotor, and search activity of rats in the "open field" and "elevated plus maze" tests demonstrated the ability of FFIs to reduce stressful behavior induced by immobilization. The improvement in the long-term memory of animals treated with FFIs was noted in the passive avoidance test. Together with the hypolipidemic effect and compensation of transaminase levels, FFIs normalized the excretion of catecholamines in the urine and reduced the levels of malondialdehyde to values of the control group. According to the results of the assessment of FFI acute oral toxicity, the LD₅₀ value exceeded 5000 mg/kg of body weight, which categorizes the FFIs under hazard class 5-substances with low hazard. The conducted experiment demonstrated the effectiveness of nutritional support with FFIs on the selected stress model. The positive safety profile of FFIs makes them reasonable to study on other stress models and to conduct clinical testing as part of specialized food products in various categories of people exposed to chronic stress.

PAMAM-Calix-Dendrimers: Second Generation Synthesis, Fluorescent Properties and Catecholamines Binding

A convenient method for the synthesis of the second generation of PAMAM dendrimers based on a p-tert-butylthiacalix[4]arene core in cone, partial cone and 1,3-alternate conformations was developed. Unusual fluorescence of the obtained PAMAM-calix-dendrimers has been found and explained. The binding ability of the synthesized dendrimers toward catecholamines (dopamine, L-adrenaline and L-noradrenaline) was shown by UV-Vis, fluorescence, 1D and 2D NMR spectroscopy and the binding constants (logK_a 3.85-4.74) calculated. As was shown, the PAMAM-calix-dendrimers bind catecholamines by the internal cavities. All the studied hormones were most efficiently bound by the dendrimers bearing a macrocyclic core in 1,3-alternate conformation. The size of the formed supramolecular systems of dendrimer/catecholamine was established by the DLS method. A decrease in hemolytic activity of the PAMAM-calix-dendrimers with an increase in the generation number of a dendrimer was shown for the dendrimers with a core in 1,3-alternate conformation. The prospects for the use of the synthesized dendrimers with the macrocyclic core as drug delivery agents were discussed.

Spatial contextual recognition memory updating is modulated by dopamine release in the dorsal hippocampus from the locus coeruleus

Detecting novelty is critical to consolidate declarative memories, such as spatial contextual recognition memory. It has been shown that stored memories, when retrieved, are susceptible to modification, incorporating new information through an updating process. Catecholamine release in the hippocampal CA1 region consolidates an object location memory (OLM). This work hypothesized that spatial contextual memory updating could be changed by decreasing catecholamine release in the hippocampal CA1 terminals from the locus coeruleus (LC). In a mouse model expressing Cre-recombinase under the control of the tyrosine hydroxylase (TH) promoter, memory updating was impaired by photoinhibition of the CA1 catecholaminergic terminals from the LC (LC-CA1) but not from the ventral tegmental area (VTA-CA1). In vivo microdialysis confirmed that the extracellular concentration of both dopamine (DA) and noradrenaline (NA) decreased after photoinhibition of the LC-CA1 terminals (but not VTA-CA1) during the OLM update session. Furthermore, DA D1/D5 and beta-adrenergic receptor antagonists disrupted behavior, but only the former impaired memory updating. Finally, photoinhibition of LC-CA1 terminals suppressed long-term potentiation (LTP) induction in Schaffer's collaterals as a plausible mechanism for memory updating. These data will help understand the underpinning mechanisms of DA in spatial contextual memory updating.

Epistaxis, paroxysmal anxiety episodes, and hypertension in a child with SDHB-associated paraganglioma: A case report

A child presented with anxiety and weight gain which were overlooked until she had epistaxis. She was found to have hypertension secondary to paraganglioma. She was managed with curative surgery involving multidisciplinary care. The tumor removal led to the amelioration of symptoms and marked control of hypertension.

Takotsubo Cardiomyopathy and β-Blocker Poisoning: A Case Report

β-blocker poisoning is frequently observed because of its primary use for the treatment of cardiovascular diseases. The management of β-blocker toxicity is dependent on the cardiovascular response and the severity of presentation. The present study describes the case of a patient with combined drug intoxication, β-blocker, digoxin, benzodiazepines, acetaminophen and opiates in a suicidal attempt. A 63-year-old female was found somnolent and in a confused state at her residence following intentional poly-drug ingestion. Upon presentation, she was found to be hemodynamically unstable and was thus treated with vasopressors. The toxicological screening performed upon presentation was positive for polydrug ingestion. On day 3, the patient developed chest pain and ST-segment elevation in anterior leads, while transthoracic echocardiographic assessment disclosed a non-dilated left ventricle with moderate dysfunction and akinesia of the apex. Coronary angiogram revealed normal coronary arteries and, subsequently, the diagnosis of Takotsubo cardiomyopathy (TTC) was suspected. Supportive treatment was initiated with favorable evolution and left ventricular ejection fraction normalization. The management of hemodynamic instability with vasopressors should be judiciously administered in the treatment of β-blocker poisoning, in view of the adverse effects on cardiac functions, including stress cardiomyopathy.

Stress exacerbates pancreatic cancer both directly and indirectly by creating an immunosuppressive environment

BACKGROUND/PURPOSE

Sympathetic nerve stimulation by stress exacerbates various solid tumors, including pancreatic cancer (PCa). The relationship between cancer and immunity has been suggested; however, there is limited information about the effects of nerve stimulation on immunity and cancer. We aimed to investigate the involvement of sympathetic nerve stimulation in immune cells and its effects on PCa using a restraint stress mouse model.

METHODS

In the in vitro experiment, the mouse-derived PCa cell line (LTPA) was cultured in a noradrenalin-supplemented medium. In the in vivo experiment, mice were divided into non-stress and stress groups.

RESULTS

LTPA proliferated significantly more when cultured in a noradrenalin-supplemented medium than in a normal medium. Flow cytometry analysis of blood immune cells revealed a significant decrease in B cells, T cells, and macrophages and a significant increase in myeloid-derived suppressor cells (MDSCs) in the stress group. Furthermore, a significant increase in blood noradrenaline levels was observed in the stress group (p < .01). In the PCa mice model, immune cells in the blood showed a similar trend, and the stress group had a poor prognosis. Furthermore, immunostaining at the tumor site showed that there was a lower number of B and T cells in the stress group. In addition, MDSCs were present at the tumor margins.

CONCLUSION

These results suggest that sympathetic nerve stimulation is not only directly involved in PCa growth but also exacerbates PCa by creating an immunosuppressive environment in the blood and tumor tissue.

Saxagliptin: A potential doping agent? A randomized, double-blinded, placebo-controlled, and crossover pilot study in young active men

Neuropeptide Ys (NPYs) contribute to sympathetic-adreno stimulation: NPY1-36 potentiates the effects of catecholamines (CATs), whereas NPY3-36 inhibits CAT release. We sought to investigate whether inhibiting dipeptidyl-peptidase-4 (DPP4), cleaving NPY1-36 into NPY3-36, leads to increased NPY1-36 potentiating effects and reduced NPY3-36 inhibitory effects on CATs, thereby improving endurance performance. Seven male participants (age 27 ± 3 years, BMI 23.1 ± 2.4 kg/m² ) performed time-to-exhaustion cycling exercise at 95% of peak power output with either placebo, or saxagliptin, a DPP4 inhibitor. Oxygen consumption (V̇O₂ ), heart rate variability, NPY1-36, NPY3-36, catecholamines, and lactate were measured at several time points before, during, and after exercise. With saxagliptin, DPP4 activity (12.7 ± 1.6 vs. 0.2 ± 0.3 U/L, p = 0.001; d = 10.7) was decreased at rest, while NPY3-36 (1.94 ± 0.88 vs. 0.73 ± 0.22 pm; p < 0.001; d = 2.04) decreased and NPY1-36 increased during exercise (2.64 ± 2.22 vs. 4.59 ± 2.98 pm; p < 0.01; d = 0.19). CATs were unchanged. Time-to-exhaustion was 32% higher with saxagliptin. The difference in time-to-exhaustion between placebo and saxagliptin was correlated with NPY1-36 differences (R = 0.78, p < 0.05). Peak V̇O₂ and other cardio-respiratory values were not different, whereas peak NPY concentrations were higher with saxagliptin. DPP4 blockade improved performance, increased NPY1-36, and decreased NPY3-36 concentrations which may have potentiating effects on the influences of CATs. However, DPP4 is involved in many different actions, thus NPYs are one group of factors that may underly its performance-enhancing effects; further studies are required to determine the exact mechanisms.

Effects of catheter-based renal denervation on renin-aldosterone system, catecholamines, and electrolytes: A systematic review and meta-analysis

In recent years, catheter-based renal denervation (RDN) has emerged as a promising instrumental therapy for hypertension. The interruption of sympathetic nervous system was regarded as a possible mechanism for RDN regulating blood pressure. While the results reflected by renin-angiotensin-aldosterone system (RAAS), catecholamines and electrolytes remained inconsistent and was never systematically assessed. Pubmed, Embase, and Web of Science were comprehensively searched from inception to September 5, 2021. Studies that evaluated the effects of RDN on RAAS, catecholamines, and electrolytes were identified. Primary outcomes were changes in RAAS hormones after RDN, and secondary outcomes involved changes in plasma norepinephrine, serum, and urinary sodium and potassium. Out of 6391 retrieved studies, 20 studies (two randomized controlled studies and 18 observational studies) involving 771 persons were eventually included. Plasma renin activity had a statistically significant reduction after RDN (0.24 ng/mL/h, 95% CI 0.04 to 0.44, P = .02). While no significant change was found regarding plasma aldosterone (1.53 ng/dL, 95% CI -0.61 to 3.67, P = .16), norepinephrine (0.42 nmol/L, 95% -0.51 to 1.35, P = 0.38), serum sodium and potassium (0.16 mmol/L, 95% CI -0.17 to 0.49, P = .34; -0.02 mmol/L, 95% CI -0.09 to 0.04, P = .48, respectively), and urinary sodium and potassium (3.95 mmol/24 h, 95% CI -29.36 to 37.26, P = .82; 10.22 mmol/24 h, 95% CI -12.11 to 32.54, P = .37, respectively). In conclusion, plasma renin activity significantly decreased after RDN, while no significant change was observed in plasma aldosterone, plasma norepinephrine, and serum and urinary electrolytes.

Clonidine suppression test for a reliable diagnosis of pheochromocytoma: When to use

OBJECTIVE

In clinical practice, false-positive results in biochemical testing for suspected pheochromocytoma/paraganglioma (PPGL) are not infrequent and may lead to unnecessary examinations. We aimed to evaluate the role of the clonidine suppression test (CST) in the era of analyses of plasma-free metanephrines for the diagnosis or exclusion of PPGL in patients with adrenal tumours and/or arterial hypertension.

DESIGN AND METHODS

This single-centre, prospective trial investigated the use of CST in 60 patients with suspected PPGL associated with out-patient elevations of plasma normetanephrine (NMN) and/or metanephrine (MN), in most cases accompanied with hypertension or an adrenal mass. Measurements of plasma catecholamines and free metanephrines were performed by liquid chromatography with electrochemical detection and tandem mass spectrometry, respectively.

RESULTS

Forty-six patients entered final analysis (n = 20 with PPGL and n = 26 with a nonfunctional adrenal mass and/or hypertension). CST reliably excluded false-positive baseline NMN results with a specificity of 100%. The sensitivity of CST improved from 85% to 94% when tumours with isolated MN increase (n = 3) were not considered. In patients with elevated baseline NMN (n = 24), CST correctly identified all patients without PPGL. Patients with falsely elevated baseline NMN results (n = 7, 26.9%) exhibited increases of baseline NMN up to 1.7-fold above the upper reference limit.

CONCLUSION

CST qualifies as a useful diagnostic tool for differential diagnosis of borderline elevated plasma-free NMN in patients with suspected PPGL. In this context, CST helps to correctly identify all false-positive NMN screening results.

Hypertension, Anxiety and Obstructive Sleep Apnea in Cardiovascular Disease and COVID-19: Mediation by Dietary Salt

This perspective paper used a grounded theory method to synthesize evidence proposing that sodium toxicity from excessive dietary salt intake is a potential common pathophysiological mechanism that mediates the association of hypertension, obstructive sleep apnea, and anxiety with cardiovascular disease and COVID-19. Increased anxiety in these conditions may be linked to a high-salt diet through stimulation of the sympathetic nervous system, which increases blood pressure while releasing catecholamines, causing a "fight or flight" response. A rostral shift of fluid overload from the lower to the upper body occurs in obstructive sleep apnea associated with COVID-19 and cardiovascular disease, and may be related to sodium and fluid retention triggered by hypertonic dehydration. Chronic activation of the renin-angiotensin-aldosterone system responds to salt-induced dehydration by increasing reabsorption of sodium and fluid, potentially exacerbating fluid overload. Anxiety may also be related to angiotensin II that stimulates the sympathetic nervous system to release catecholamines. More research is needed to investigate these proposed interrelated mechanisms mediated by dietary salt. Furthermore, dietary interventions should use a whole-food plant-based diet that eliminates foods processed with salt to test the effect of very low sodium intake levels on hypertension, anxiety, and obstructive sleep apnea in cardiovascular disease and COVID-19.

Low and Moderate Doses of Caffeinated Coffee Improve Repeated Sprint Performance in Female Team Sport Athletes

The aim of this study was to determine the effect of low and moderate doses of caffeine ingestion via caffeinated coffee on repeated sprint test (RST) and plasma catecholamine concentration in trained female team-sport athletes. In a randomized, double-blind, crossover design, 13 female team-sport athletes (VO2max: 48.7 ± 4 mL·kg·min−1) completed three RST trials, separated by 4-day, 60 min post-ingestion of either 3 mg·kg−1 (LCOF) or 6 mg·kg−1 (MCOF) or placebo (PLA). The RST consisted of 12 × 4 s sprints on a cycle ergometer interspersed with 20 s of active recovery. Blood lactate (BLa) and glucose (GLU) and epinephrine and norepinephrine concentrations were collected before and 60 min after coffee ingestion, and after RST. Heart rate (HR) and ratings of perceived exertion (RPE) were measured at the beginning of RST, and after the 6th and 12th sprints. Average peak power score during RST was significantly improved after LCOF (p = 0.016) and MCOF (p = 0.041) compared to PLA, but peak and mean power output of the individual sprints, and fatigue index were not different between trials (all p > 0.05). Epinephrine and norepinephrine concentrations were significantly higher before and after RST in LCOF and MCOF compared to PLA (all p < 0.05). BLa was also higher after RST in both LCOF and MCOF compared to PLA (p = 0.005). HR, RPE, and GLU were not different between conditions (p > 0.05). In conclusion, low and moderate dose of caffeine ingestion can enhance the average peak power score during repeated sprints. These findings partly support low and moderate doses of caffeine supplementation via coffee as a nutritional ergogenic aid for trained female team-sport players during repeated sprint exercise.

Long-Term Excessive Dietary Phosphate Intake Increases Arterial Blood Pressure, Activates the Renin-Angiotensin-Aldosterone System, and Stimulates Sympathetic Tone in Mice

Increased dietary phosphate intake has been associated with severity of coronary artery disease, increased carotid intima–media thickness, left ventricular hypertrophy (LVH), and increased cardiovascular mortality and morbidity in individuals with normal renal function as well as in patients suffering from chronic kidney disease. However, the underlying mechanisms are still unclear. To further elucidate the cardiovascular sequelae of long-term elevated phosphate intake, we maintained male C57BL/6 mice on a calcium, phosphate, and lactose-enriched diet (CPD, 2% Ca, 1.25% P, 20% lactose) after weaning them for 14 months and compared them with age-matched male mice fed a normal mouse diet (ND, 1.0% Ca, 0.7% P). Notably, the CPD has a balanced calcium/phosphate ratio, allowing the effects of elevated dietary phosphate intake largely independent of changes in parathyroid hormone (PTH) to be investigated. In agreement with the rationale of this experiment, mice maintained on CPD for 14 months were characterized by unchanged serum PTH but showed elevated concentrations of circulating intact fibroblast growth factor-23 (FGF23) compared with mice on ND. Cardiovascular phenotyping did not provide evidence for LVH, as evidenced by unchanged LV chamber size, normal cardiomyocyte area, lack of fibrosis, and unchanged molecular markers of hypertrophy (Bnp) between the two groups. However, intra-arterial catheterization revealed increases in systolic pressure, mean arterial pressure, and pulse pressure in mice fed the CPD. Interestingly, chronically elevated dietary phosphate intake stimulated the renin–angiotensin–aldosterone system (RAAS) as evidenced by increased urinary aldosterone in animals fed the CPD, relative to the ND controls. Furthermore, the catecholamines epinephrine, norepinephrine, and dopamine as well as the catecholamine metabolites metanephrine. normetanephrine and methoxytyramine as measured by mass spectrometry were elevated in the urine of mice on CPD, relative to mice on the ND. These changes were partially reversed by switching 14-month-old mice on CPD back to ND for 2 weeks. In conclusion, our data suggest that excess dietary phosphate induces a rise in blood pressure independent of secondary hyperparathyroidism, and that this effect may be mediated through activation of the RAAS and stimulation of the sympathetic tone.

Lipolysis defect in people with obesity who undergo metabolic surgery

OBJECTIVE

Cross-sectional studies demonstrate that catecholamine stimulation of fat cell lipolysis is blunted in obesity. We investigated whether this defect persists after substantial weight loss has been induced by metabolic surgery, and whether it is related to the outcome.

DESIGN/METHODS

Patients with obesity not able to successfully reduce body weight by conventional means (n = 126) were investigated before and 5 years after Roux-en-Y gastric bypass surgery (RYGB). They were compared with propensity-score matched subjects selected from a control group (n = 1017), and with the entire group after adjustment for age, sex, body mass index (BMI), fat cell volume and other clinical parameters. Catecholamine-stimulated lipolysis (glycerol release) was investigated in isolated fat cells using noradrenaline (natural hormone) or isoprenaline (synthetic beta-adrenoceptor agonist).

RESULTS

Following RYGB, BMI was reduced from 39.9 (37.5-43.5) (median and interquartile range) to 29.5 (26.7-31.9) kg/m² (p < 0.0001). The post-RYGB patients had about 50% lower lipolysis rates compared with the matched and total series of controls (p < 0.0005). Nordrenaline activation of lipolysis at baseline was associated with the RYGB effect; those with high lipolysis activation (upper tertile) lost 30%-45% more in body weight, BMI or fat mass than those with low (bottom tertile) initial lipolysis activation (p < 0.0007).

CONCLUSION

Patients with obesity requiring metabolic surgery have impaired ability of catecholamines to stimulate lipolysis, which remains despite long-term normalization of body weight by RYGB. Furthermore, preoperative variations in the ability of catecholamines to activate lipolysis may predict the long-term reduction in body weight and fat mass.

Propofol-Related Infusion Syndrome: A Clinical Review

Propofol-related infusion syndrome (PRIS) is a lethal condition characterized by multiple organ system failures. It can occur due to prolonged administration of propofol (an anesthetic) in mechanically intubated patients. The main presenting features of this condition include cardiovascular dysfunction with particular emphasis on impairment of cardiovascular contractility, metabolic acidosis, lactic acidosis, rhabdomyolysis, hyperkalaemia, lipidaemia, hepatomegaly, acute renal failure, and eventually mortality in most cases. The significant risk factors that predispose one to PRIS are: critical illnesses, increased serum catecholamines, steroid therapy, obesity, young age (significantly below three years), depleted carbohydrate stores in the body, increased serum lipids, and most importantly, heavy or extended dosage of propofol. The primary pathophysiology behind PRIS is the disruption of the mitochondrial respiratory chain that causes inhibition of adenosine triphosphate (ATP) synthesis and cellular hypoxia. Further, excess lipolysis of adipose tissue occurs, especially in critically ill patients where the energy source is lipid breakdown instead of carbohydrates. This process generates excess free fatty acids (FFAs) that cannot undergo adequate beta-oxidation. These FFAs contribute to the clinical pathology of PRIS. It requires prompt management as it is a fatal condition. The clinicians must observe the patient's electrocardiogram (ECG), serum creatine kinase, lipase, amylase, lactate, liver enzymes, and myoglobin levels in urine, under propofol sedation. Doctors should immediately stop propofol infusion upon noticing any abnormality in these parameters. The other essentials of management of various manifestations of PRIS will be discussed in this article, along with a detailed explanation of the condition, its risk factors, diagnosis, pathophysiology, and presenting features. This article aims to make clinicians more aware of the occurrence of this syndrome so that better ways to manage and treat this condition can be formulated in the future.

Workplace Culture and Biomarkers of Health Risk

Workplace culture has been studied for impact on health risk; however, connections with robust biologic markers of health remain to be established. We examined associations between the work environment and urinary levels of catecholamines and their metabolites as biomarkers of sympathetic nervous system activity, indicative of stress. We recruited participants (n = 219; 2018-2019) from a cardiovascular risk cohort to investigate workplace culture, well-being, and stress. Participants completed seven questionnaires. Urine samples were used to measure catecholamines and their metabolites by LC/MS/MS. Pearson correlation and linear regression models were used after adjusting for demographics and creatinine. Participants reporting higher well-being had lower urinary levels of dopamine, serotonin, and 3-methoxytyramine. Participants reporting a more engaged and more positive workplace had lower levels of dopamine and 3-methoxytyramine. Reported workplace isolation was correlated with higher levels of dopamine and 3-methoxytyramine. Given correlations between catecholamines, we used 3-methoxytyramine for linear regression. In fully adjusted models, in environments with a more positive culture, levels of 3-methoxytyramine remained lower (β = -0.065 ± 0.025, p = 0.01) and indicated a positive association between workplace isolation and 3-methoxytyramine (β = 0.064 ± 0.030, p = 0.04). These findings are consistent with an important relationship between workplace environment and sympathetic nervous system activity.

The effect of obstructive sleep apnea therapy on cardiovascular autonomic function: a systematic review and meta-analysis

STUDY OBJECTIVES

Autonomic function is impaired in obstructive sleep apnea (OSA) and may mediate the association between OSA and cardiovascular risk. We investigated the effect of OSA therapy on autonomic function through a systematic review and meta-analysis of intervention studies.

METHODS

A systematic search using three databases (Medline, Embase, and Scopus) was performed up to December 9, 2020. Studies of OSA patients ≥ 18 years with autonomic function assessed before and after treatment with positive airway pressure, oral appliance, positional therapy, weight loss, or surgical intervention were included for review. Random effects meta-analysis was carried out for five groups of autonomic function indices. Risk of bias was assessed using the Cochrane Collaboration tool.

RESULTS

Forty-three eligible studies were reviewed with 39 included in the meta-analysis. OSA treatment led to large decreases in muscle sympathetic nerve activity (Hedges' g = -1.08; 95% CI -1.50, -0.65, n = 8) and moderate decreases in catecholamines (-0.60; -0.94, -0.27, n = 3) and radio nucleotide imaging (-0.61; -0.99, -0.24, n = 2). OSA therapy had no significant effect on baroreflex function (Hedges' g = 0.15; 95% CI -0.09, 0.39, n = 6) or heart rate variability (0.02; -0.32, 0.36, n = 14). There was a significant risk of bias due to studies being primarily non-randomized trials.

CONCLUSIONS

OSA therapy selectively improves autonomic function measures. The strongest evidence for the effect of OSA therapy on autonomic function was seen in reduced sympathetic activity as assessed by microneurography, but without increased improvement in parasympathetic function. OSA therapy may reduce the risk of cardiovascular disease in OSA through reduced sympathetic activity.

Importance of catecholamine signaling in the development of platelet exhaustion after traumatic injury

BACKGROUND

Impaired ex vivo platelet aggregation is common in trauma patients. The mechanisms driving these impairments remain incompletely understood, but functional platelet exhaustion due to excessive in vivo activation is implicated. Given platelet adrenoreceptors and known catecholamine surges after injury, impaired ex vivo platelet aggregation in trauma patients may be linked to catecholamine-induced functional platelet exhaustion.

OBJECTIVE

To determine the relationship of catecholamines with platelet-dependent hemostasis after injury and to model catecholamine-induced functional platelet exhaustion in healthy donor platelets.

PATIENTS/METHODS

Whole blood was collected from 67 trauma patients as part of a prospective cohort study. Platelet aggregometry and rotational thromboelastometry were performed, and plasma epinephrine (EPI) and norepinephrine (NE) concentrations were measured. The effect of catecholamines on healthy donor platelets was examined in a microfluidic model, with platelet aggregometry, and by flow cytometry examining surface markers of platelet activation.

RESULTS

In trauma patients, EPI and NE were associated with impaired platelet aggregation (both p < 0.05), and EPI was additionally associated with decreased viscoelastic clot strength, increased fibrinolysis, and mortality (all p < 0.05). In healthy donors, short duration incubation with EPI enhanced platelet aggregation, platelet adhesion under flow, and increased glycoprotein IIb/IIIa activation, while weaker effects were observed with NE. Compared with short incubation, longer incubation with EPI resulted in decreased platelet adhesion, platelet aggregation, and surface expression of glycoprotein IIb/IIIa.

CONCLUSIONS

These findings suggest sympathoadrenal activation in trauma patients contributes to impaired ex vivo platelet aggregation, which mechanistically may be explained by a functionally exhausted platelet phenotype under prolonged exposure to high plasma catecholamine levels.

Serum Catestatin Levels Correlate with Ambulatory Blood Pressure and Indices of Arterial Stiffness in Patients with Primary Hypertension

Accumulating data suggests that catestatin, an eclectic neuroendocrine peptide, is involved in the pathophysiology of primary hypertension (PH). Nevertheless, clinical studies concerning its role in PH are still scarce. Therefore, in the present study, we aimed to explore an association between serum catestatin levels, ambulatory blood pressure (BP) and arterial stiffness in patients with PH and healthy controls. In this single-center study, 72 patients aged 40−70 diagnosed with PH, and 72 healthy controls were included. In patients with PH, serum catestatin concentrations were significantly higher in comparison to the healthy controls (29.70 (19.33−49.48) ng/mL vs. 5.83 (4.21−8.29) ng/mL, p < 0.001). Untreated patients had significantly higher serum catestatin than patients treated with antihypertensive drugs (41.61 (22.85−63.83) ng/mL vs. 24.77 (16.41−40.21) ng/mL, p = 0.005). Multiple linear regression analysis showed that serum catestatin levels retained a significant association with mean arterial pressure (β ± standard error, 0.8123 ± 0.3037, p < 0.009) after model adjustments for age, sex and body mass index. Finally, catestatin levels positively correlated with pulse wave velocity (r = 0.496, p < 0.001) and central augmentation index (r = 0.441, p < 0.001), but not with peripheral resistance. In summary, increased serum catestatin concentration in PH, predominantly in the untreated subgroup, and its association with ambulatory BP and arterial stiffness address the role of this peptide in PH.

Natural photoredox catalysts promote light-driven lytic polysaccharide monooxygenase reactions and enzymatic turnover of biomass

Lytic polysaccharide monooxygenases (LPMOs) catalyze oxidative cleavage of crystalline polysaccharides such as cellulose and chitin and are important for biomass conversion in the biosphere as well as in biorefineries. The target polysaccharides of LPMOs naturally occur in copolymeric structures such as plant cell walls and insect cuticles that are rich in phenolic compounds, which contribute rigidity and stiffness to these materials. Since these phenolics may be photoactive and since LPMO action depends on reducing equivalents, we hypothesized that LPMOs may enable light-driven biomass conversion. Here, we show that redox compounds naturally present in shed insect exoskeletons enable harvesting of light energy to drive LPMO reactions and thus biomass conversion. The primary underlying mechanism is that irradiation of exoskeletons with visible light leads to the generation of H₂O₂, which fuels LPMO peroxygenase reactions. Experiments with a cellulose model substrate show that the impact of light depends on both light and exoskeleton dosage and that light-driven LPMO activity is inhibited by a competing H₂O₂-consuming enzyme. Degradation experiments with the chitin-rich exoskeletons themselves show that solubilization of chitin by a chitin-active LPMO is promoted by light. The fact that LPMO reactions, and likely reactions catalyzed by other biomass-converting redox enzymes, are fueled by light-driven abiotic reactions in nature provides an enzyme-based explanation for the known impact of visible light on biomass conversion.

Hypermetabolism and Substrate Utilization Rates in Pheochromocytoma and Functional Paraganglioma

The overproduction of catecholamines in pheochromocytoma/paraganglioma (PPGL) induces a hypermetabolic state. The aim of this study was to evaluate the incidence of a hypermetabolic state and differences in substrate metabolism in consecutive PPGL patients divided by catecholamine phenotype. Resting energy expenditure (REE) and respiratory quotient (RQ) were measured in 108 consecutive PPGL patients and 70 controls by indirect calorimetry. Hypermetabolic state was defined according to the Mifflin St. Jeor Equation as a ratio above 110%. Hypermetabolic state was confirmed in 70% of PPGL patients, regardless of phenotype. Older age, prevalence of diabetes mellitus and arterial hypertension were correlated with hypermetabolic PPGL as compared to normometabolic form. Analysis according to overproduced catecholamine showed differences in VCO2 (p < 0.05) and RQ (p < 0.01) and thus different substate metabolism between phenotypes in hypermetabolic form of PPGL. Lipid utilization was higher in the adrenergic phenotype (p = 0.001) and positively associated with the percentage of REE ratio (R = 0.48, p < 0.001), whereas the noradrenergic phenotype preferentially oxidizes carbohydrates (P = 0.001) and is correlated with the percentage of REE ratio (R = 0.60, p < 0.001). Hypermetabolic state in PPGL is a common finding in both catecholamine phenotypes. Hypermetabolic PPGL patients are older and suffer more from diabetes mellitus and arterial hypertension. Under basal conditions, the noradrenergic type preferentially metabolizes carbohydrates, whereas the adrenergic phenotype preferentially metabolizes lipids.

Epinephrine evokes shortening of human airway smooth muscle cells following β2 adrenergic receptor desensitization

Epinephrine (EPI), an endogenous catecholamine involved in the body's fight-or-flight responses to stress, activates α1-adrenergic receptors (α1ARs) expressed on various organs to evoke a wide range of physiological functions, including vasoconstriction. In the smooth muscle of human bronchi, however, the functional role of EPI on α1ARs remains controversial. Classically, evidence suggests that EPI promotes bronchodilation by stimulating β2-adrenergic receptors (β2ARs). Conventionally, the selective β2AR agonism of EPI was thought to be, in part, due to a predominance of β2ARs and/or a sparse, or lack of α1AR activity in human airway smooth muscle (HASM) cells. Surprisingly, we find that HASM cells express a high abundance of ADRA1B (the α1AR subtype B) and identify a spontaneous "switch-like" activation of α1ARs that evokes intracellular calcium, myosin light chain phosphorylation, and HASM cell shortening. The switch-like responses, and related EPI-induced biochemical and mechanical signals, emerged upon pharmacological inhibition of β2ARs and/or under experimental conditions that induce β2AR tachyphylaxis. EPI-induced procontractile effects were abrogated by an α1AR antagonist, doxazosin mesylate (DM). These data collectively uncover a previously unrecognized feed-forward mechanism driving bronchospasm via two distinct classes of G protein-coupled receptors (GPCRs) and provide a basis for reexamining α1AR inhibition for the management of stress/exercise-induced asthma and/or β2-agonist insensitivity in patients with difficult-to-control, disease subtypes.

Non-Targeted Metabolomics Approach Revealed Significant Changes in Metabolic Pathways in Patients with Chronic Traumatic Encephalopathy

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease that is frequently found in athletes and those who have experienced repetitive head traumas. CTE is associated with a variety of neuropathologies, which cause cognitive and behavioral impairments in CTE patients. However, currently, CTE can only be diagnosed after death via brain autopsy, and it is challenging to distinguish it from other neurodegenerative diseases with similar clinical features. To better understand this multifaceted disease and identify metabolic differences in the postmortem brain tissues of CTE patients and control subjects, we performed ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS)-based non-targeted metabolomics. Through multivariate and pathway analysis, we found that the brains of CTE patients had significant changes in the metabolites involved in astrocyte activation, phenylalanine, and tyrosine metabolism. The unique metabolic characteristics of CTE identified in this study were associated with cognitive dysfunction, amyloid-beta deposition, and neuroinflammation. Altogether, this study provided new insights into the pathogenesis of CTE and suggested appealing targets for both diagnosis and treatment for the disease.

Primers for the Adhesion of Gellan Gum-Based Hydrogels to the Cartilage: A Comparative Study

A stable adhesion to the cartilage is a crucial requisite for hydrogels used for cartilage regeneration. Indeed, a weak interface between the tissue and the implanted material may produce a premature detachment and thus the failure of the regeneration processes. Fibrin glue, cellulose nanofibers and catecholamines have been proposed in the state-of-the-art as primers to improve the adhesion. However, no studies focused on a systematic comparison of their performance. This work aims to evaluate the adhesion strength between ex vivo cartilage specimens and polysaccharide hydrogels (gellan gum and methacrylated gellan gum), by applying the mentioned primers as intermediate layer. Results show that the fibrin glue and the cellulose nanofibers improve the adhesion strength, while catecholamines do not guarantee reaching a clinically acceptable value. Stem cells embedded in gellan gum hydrogels reduce the adhesion strength when fibrin glue is used as a primer, being anyhow still sufficient for in vivo applications. This article is protected by copyright. All rights reserved.

The effect of acid use as a preservative on the results of biochemical tests measured in 24-h urine

Twenty-four-hour urine measurements play a crucial role in the diagnosis, follow-up and treatment of various diseases. There are different approaches to the collection of urine in patients who need to collect multiple urine samples at a time, especially in hospitals with heavy workloads. In this study, we compared the sodium, potassium, chloride, amylase, calcium, creatinine, phosphorus, microalbumin, protein, magnesium, urea, uric acid, adrenaline, noradrenaline, dopamine, metanephrine, normetanephrine, vanillylmandelic acid, 5-hydroxyindoleacetic acid and homovanillic acid results of 24-h urine samples analyzed immediately without acid addition, which we accepted as the reference and baseline measurement, with the results of the samples analyzed after waiting for 24 h without acid addition, analyzed immediately with acid addition and analyzed after waiting for 24 h with acid addition. Chloride, microalbumin, amylase and protein tests, which are recommended to be measured in the sample without preservatives, are affected by acid addition. Adrenaline, noradrenaline and dopamine, which are the tests recommended to be measured in acid-added urine are degraded in the samples without acid, and the levels of metanephrine and normetanephrine were not significantly degraded in the absence of preservatives.