Beta-adrenergic blockade has been associated with improved cancer survival in patients with triple-negative breast cancer (TNBC), but the mechanisms of these effects remain unclear. In clinical epidemiological analyses, we identified a relationship between beta-blocker use and anthracycline chemotherapy in protecting against TNBC progression, disease recurrence, and mortality. We recapitulated the effect of beta-blockade on anthracycline efficacy in xenograft mouse models of TNBC. In metastatic 4T1.2 and MDA-MB-231 mouse models of TNBC, beta-blockade improved the efficacy of the anthracycline doxorubicin by reducing metastatic development. We found that anthracycline chemotherapy alone, in the absence of beta-blockade, increased sympathetic nerve fiber activity and norepinephrine concentration in mammary tumors through the induction of nerve growth factor (NGF) by tumor cells. Moreover, using preclinical models and clinical samples, we found that anthracycline chemotherapy up-regulated β 2 -adrenoceptor expression and amplified receptor signaling in tumor cells. Neurotoxin inhibition of sympathetic neural signaling in mammary tumors using 6-hydroxydopamine or genetic deletion of NGF or β 2 -adrenoceptor in tumor cells enhanced the therapeutic effect of anthracycline chemotherapy by reducing metastasis in xenograft mouse models. These findings reveal a neuromodulatory effect of anthracycline chemotherapy that undermines its potential therapeutic impact, which can be overcome by inhibiting β 2 -adrenergic signaling in the tumor microenvironment. Supplementing anthracycline chemotherapy with adjunctive β 2 -adrenergic antagonists represents a potential therapeutic strategy for enhancing the clinical management of TNBC.
Mechanisms underlying post-stroke immune impairments and subsequent development of fatal lung infection have been suggested to involve multiple pathways, including hyperactivation of the sympathetic nervous system (SNS), which results in the excessive release of catecholamines and activation of β-adrenergic receptors (βARs). Indeed, previous reports from experimental studies demonstrated that post-stroke infection can be inhibited with treatment of β-blockers. However, the effectiveness of β-blockers in reducing post-stroke infection has yielded mixed results in retrospective clinical trials and its use remain controversial. In this study, we performed mid-cerebral artery occlusion in mice either genetically deficient in β2-adrenergic receptor (β2AR) or treated with non-selective and selective βAR antagonists to explore the contributions of the SNS in the development of post-stroke lung infection. Stroke induced a systemic activation of the SNS as indicated by elevated levels of plasma catecholamines and UCP-1 activity. However, β2AR deficient mice showed similar degrees of post-stroke immune impairment and infection rate compared to wildtype counterparts, potentially due to compensatory mechanisms common in transgenic animals. To overcome this, we treated post-stroke wildtype mice with pharmacological inhibitors of the βARs, including the non-selective antagonist propranolol (PPL) and selective β2AR antagonist ICI-118551. Both pharmacological strategies to block the action of SNS signalling were unable to reduce infection in mice that underwent ischaemic stroke. Overall, our data suggests that other mechanisms independent or in combination with β2AR activation contribute to the development of post-stroke infection.
Key points Controversy exists about the physiological mechanism(s) underlying decreases in cardiac output after immediate clamping of the umbilical cord at birth. To define these mechanisms, the four major determinants of ventricular output (afterload, preload, heart rate and contractility) were measured concurrently in fetal lambs at 15 s intervals over a 2 min period after cord clamping and before ventilation following delivery. After cord clamping, right (but not left) ventricular output fell by 20% in the initial 30 s, due to increased afterload associated with higher arterial blood pressures, but both outputs then halved over 45 s, due to a falling heart rate and deteriorating ventricular contractility accompanying rapid declines in arterial oxygenation to asphyxial levels. Ventricular outputs subsequently plateaued from 75 to 120 s, associated with rebound rises in ventricular contractility accompanying asphyxia‐induced surges in circulating catecholamines. These findings provide a physiological basis for the clinical recommendation that effective ventilation should occur within 60 s after immediate cord clamping. AbstractControversy exists about the physiological mechanism(s) underlying large decreases in cardiac output after immediate clamping of the umbilical cord at birth. To define these mechanisms, anaesthetized preterm fetal lambs (127(1)d, n = 12) were instrumented with flow probes and catheters in major central arteries, and a left ventricular (LV) micromanometer‐conductance catheter. Following immediate cord clamping at delivery, haemodynamics, LV and right ventricular (RV) outputs, and LV contractility were measured at 15 s intervals during a 2 min non‐ventilatory period, with aortic blood gases and circulating catecholamine (noradrenaline and adrenaline) concentrations measured at 30 s intervals. After cord clamping, (1) RV (but not LV) output fell by 20% in the initial 30 s, due to a reduced stroke volume associated with increased arterial blood pressures, (2) both outputs then halved over the next 45 s, associated with falls in heart rate, arterial blood pressures and ventricular contractility accompanying a rapid decline in arterial oxygenation to asphyxial levels, (3) reduced outputs subsequently plateaued from 75 to 120 s, associated with rebound rises in blood pressures and ventricular contractility accompanying exponential surges in circulating catecholamines. These findings are consistent with a time‐dependent decline of ventricular outputs after immediate cord clamping, which comprised (1) an initial, minor fall in RV output related to altered loading conditions, (2) ensuing large decreases in both LV and RV outputs related to the combination of bradycardia and ventricular dysfunction during emergence of an asphyxial state, and (3) subsequent stabilization of reduced LV and RV outputs during ongoing asphyxia, supported by cardiovascular stimulatory effects of marked sympathoadrenal activation.
BACKGROUND:High blood pressure (BP) continues to be a major, poorly controlled but modifiable risk factor for cardiovascular death. Among key Western lifestyle factors, a diet poor in fiber is associated with prevalence of high BP. The impact of lack of prebiotic fiber and the associated mechanisms that lead to higher BP are unknown. Here we show that lack of prebiotic dietary fiber leads to the development of a hypertensinogenic gut microbiota, hypertension and its complications, and demonstrate a role for G-protein coupled-receptors (GPCRs) that sense gut metabolites.METHODS:One hundred seventy-nine mice including C57BL/6J, gnotobiotic C57BL/6J, and knockout strains for GPR41, GPR43, GPR109A, and GPR43/109A were included. C57BL/6J mice were implanted with minipumps containing saline or a slow-pressor dose of angiotensin II (0.25 mg·kg-1·d-1). Mice were fed diets lacking prebiotic fiber with or without addition of gut metabolites called short-chain fatty acids ([SCFA)] produced during fermentation of prebiotic fiber in the large intestine), or high prebiotic fiber diets. Cardiac histology and function, BP, sodium and potassium excretion, gut microbiome, flow cytometry, catecholamines and methylation-wide changes were determined.RESULTS:Lack of prebiotic fiber predisposed mice to hypertension in the presence of a mild hypertensive stimulus, with resultant pathological cardiac remodeling. Transfer of a hypertensinogenic microbiota to gnotobiotic mice recapitulated the prebiotic-deprived hypertensive phenotype, including cardiac manifestations. Reintroduction of SCFAs to fiber-depleted mice had protective effects on the development of hypertension, cardiac hypertrophy, and fibrosis. The cardioprotective effect of SCFAs were mediated via the cognate SCFA receptors GPR43/GPR109A, and modulated L-3,4-dihydroxyphenylalanine levels and the abundance of T regulatory cells regulated by DNA methylation.CONCLUSIONS:The detrimental effects of low fiber Westernized diets may underlie hypertension, through deficient SCFA production and GPR43/109A signaling. Maintaining a healthy, SCFA-producing microbiota is important for cardiovascular health.
Healthcare workers core skills are reinforced and knowledge of latest developments ensured by undertaking systematic continuing professional development. The current study explored the impact of health facility location and level of care provided on the continuing professional development offered to maternity services healthcare workers in Victoria, Australia. An online survey of middle to senior management staff of 71 public and private health services as well as 7 professional bodies was conducted, yielding 114 participants. Analysis was by location (metropolitan or regional/rural) and level of care provided. The findings revealed Australian Health Practitioner Regulation Agency registration is the predominant requirement to provide continuing professional development to staff. Dedicated education departments or educators are significantly underrepresented in Level 1&2 facilities, while Level 5&6 facilities are more likely to provide breastfeeding continuing professional development. Metropolitan locations provided more wide-ranging programmes compared with rural/regional locations. Key enablers are the capacity to share resources, have access to external courses and simulation equipment/centres, and the provision of relevant and timely continuing professional development programmes, indicating that 'Educational hubs' with credentialed staff working from better resourced regional facilities could deliver a complete array of CPD programmes to lower level facilities.
In healthcare, continuing professional development is provided to ensure professional standards are maintained and for clinicians to remain fit to practice. The purpose of the study was to identify potential gaps or issues with continuing professional development in maternity services through consultations with key stakeholders and, in addition, to generate possible solutions or recommendations towards the development of a state wide continuing professional development program. The data was collected through semi-structured interviews of a purposive sample between June and August 2018. A thematic analysis was undertaken. Participants included a practicing midwife, allied health practitioner (physiotherapist), manager, healthcare educator, and an outlier service worker (maternal and child health nurse). Following the thematic analysis, four main themes (education, practitioner standards, programme monitoring and resources) were identified along with nine sub-themes. The results suggest organisations need to offer explicit support for staff to access to continuing professional development. In addition, the qualifications of facilitators of continuing professional development and/or consumer education are recommended to go beyond education levels required for registration. In this respect, some organisations credentialed their educators locally in a 'train the trainer' manner however, most participants supported professional preparation for the role of educator.
Background As surges in circulating norepinephrine and epinephrine have chronotropic, pressor, and inotropic effects, we tested the hypothesis that blunted rises in these catecholamines during preterm birth accompanied hemodynamic stability observed after early ventilation and delayed cord clamping (DCC), with findings compared to immediate cord clamping (ICC) and a non-asphyxial cord clamp-to-ventilation interval. Methods Anesthetized preterm fetal lambs were instrumented with arterial micromanometers to obtain pressure and the maximal rate of pressure rise (dP/dt max ) as a surrogate of ventricular contractility and an aortic catheter to obtain blood samples for catecholamine assay. Fetuses were delivered and mechanically ventilated before cord clamping ∼1.5 min later (DCC, n = 9) or subjected to ICC with ventilation started ∼40 s later ( n = 8). Results Perinatal hemodynamics were stable after DCC, with greater fluctuations evident following birth after ICC ( P ≤ 0.05). With DCC, circulating norepinephrine and epinephrine were unchanged after early ventilation but rose following cord clamping ( P ≤ 0.01), with concentrations below the threshold for hemodynamic effects. Norepinephrine was higher in the ICC group after cord clamping and immediately after ventilation ( P < 0.025), but catecholamine levels were otherwise similar between groups. Conclusion Hemodynamic stability at birth after DCC is accompanied by sub-threshold rises in circulating norepinephrine and epinephrine and thus blunted sympathoadrenal activation.
SummaryObjectivePolycystic ovary syndrome (PCOS) is associated with increased obesity with a greater propensity to weight gain and a lack of sustainable lifestyle interventions. Altered brown adipose tissue (BAT) thermogenesis is a potential contributor to obesity in PCOS. BAT activity and modulation have not been studied in PCOS. This observational study explored BAT thermogenesis and its associations in women with and without PCOS.Participants and methodsCutaneous temperature was recorded from supraclavicular (indicator of BAT activity) and upper arm regions using dataloggers (SubCue, Calgary, Canada) in a cross‐sectional substudy, nested within a randomized control trial, of community‐recruited premenopausal women with (n = 47, Rotterdam diagnostic criteria) and without (n = 11) PCOS.ResultsComplete temperature data were available in 44 PCOS (mean age: 30.0 ± 6.2, mean BMI: 29.3 ± 5.5) and 11 non‐PCOS (mean age: 33.0 ± 7.0, mean BMI: 25 ± 3) women. Women with PCOS had lower supraclavicular skin temperature compared to controls overall (33.9 ± 0.7 vs 34.5 ± 1, P < 0.05) and during sleep (34.5 ± 0.6 vs 35.2 ± 0.9, P < 0.001). In the PCOS group, supraclavicular skin temperature overall and over sleep and waking hours correlated inversely with testosterone (r = −0.41 P < 0.05, r = −0.485 P < 0.01 and r = −0.450 P < 0.01 respectively). Testosterone levels explained approximately 15%, 30% and 20% of the variability in supraclavicular skin temperature overall and over sleep and waking hours in women with PCOS, respectively.ConclusionWomen with PCOS have lower BAT activity compared to controls. BAT thermogenesis is negatively associated with androgen levels in PCOS.
Background: High fibre intake is associated with lower blood pressure (BP) in epidemiological and clinical studies. Prebiotic fibre resists digestion in the upper gastrointestinal tract and is fermented by gut microbiota in the intestine. The impact of lack of prebiotic dietary fibre in BP remains unknown. Objectives: To determine the consequences of lack of prebiotic dietary fibre to the development of hypertension through changes in the gut microbiome, associated receptors and immune-based mechanisms using a slow pressor angiotensin II (Ang II) model. Methods: C57BL/6 mice were fed a ‘no fibre’ or ‘high fibre’ diets for 3-weeks prior to sham or Ang II minipump implantation (n=4-21/group), and were followed for 4-weeks post-surgery. Gnotobiotic mice received faecal transplant from ‘no fibre’ sham or Ang II mice (n=5-6/group). Cardiac function, BP and gut microbiome (by 16S sequencing) were determined. Results: Ang II mice that received a ‘no fibre’ diet had significantly higher BP than sham (SBP mean±SEM: 143.7±3.5 vs 91.2±1.8, P<0.001) or ‘high fibre’ Ang II mice (143.7±3.5 vs 125.7±5mmHg, P<0.001). Transfer of a hypertensinogenic microbiota to gnotobiotic mice recapitulates the prebiotic-deprived hypertensive phenotype (93.5±3 vs 107±3mmHg, P=0.017). Re-introduction of short-chain fatty acids (SCFAs; produced during fermentation of prebiotic fibre in the large intestine) acetate, propionate and butyrate to fibre-depleted mice had protective effects on the development of hypertension (143.7±3.5 vs 93±1.2, 112.8, 115.2mmHg, respectively), cardiac hypertrophy (cardiac weight index: 5.7 vs 5.2, 5.0, 4.9mg/g) and fibrosis (25.3 vs 8.9, 12.6, 12.5%) (all P<0.05). The anti-hypertrophic effect of SCFAs were mediated via cognate SCFA receptors GPR43/GPR109A (wild-type cardiac weight index 4.53 vs 6mg/g, 11.9% vs 24.4% perivascular fibrosis, P<0.01). Fibre increased the abundance of splenic T regulatory (Treg) cells (control 4.3 vs 6.2%, P<0.001) and acetate (4.3 vs 5.1, P=0.02). Conclusions: Lack of prebiotic dietary fibre leads to the development of a hypertensinogenic gut microbiome, hypertension and its complications. SCFA might represent new therapeutic opportunities through modulation of G-coupled protein receptors and Treg cells.
Both exercise and breaks in prolonged sitting can reduce blood pressure (BP) in older overweight/obese adults. We investigated whether there is an additive hypotensive effect when exercise is combined with subsequent breaks in sitting. Sex differences and changes in plasma catecholamines as a potential candidate mechanism underlying BP responses were also examined. Sedentary older adults (n=67; 67±7 years; 31.2±4.1 kg/m 2 ) completed 3 conditions in random order—sitting (SIT): uninterrupted sitting (8 hours, control); exercise+sitting (EX+SIT): sitting (1 hour), moderate-intensity walking (30 minutes), uninterrupted sitting (6.5 hours); exercise+breaks (EX+BR): sitting (1 hour), moderate-intensity walking (30 minutes), sitting interrupted every 30 minutes with 3 minutes of light-intensity walking (6.5 hours). Serial BP and plasma epinephrine/norepinephrine measurements occurred during 8 hours. The 8-hour average systolic and diastolic BP (mm Hg 95% CI) was lower in EX+SIT −3.4 (−4.5 to −2.3), −0.8 (−1.6 to −0.04), and EX+BR −5.1 (−6.2 to −4.0), −1.1 (−1.8 to −0.3), respectively, relative to SIT (all P <0.05). There was an additional reduction in average systolic BP of −1.7 (−2.8 to −0.6) in EX+BR relative to EX+SIT ( P =0.003). This additional reduction in systolic BP was driven by women −3.2 (−4.7 to −1.7; P <0.001 EX+BR versus EX+SIT). Average epinephrine decreased in EX+SIT and EX+BR in women (−13% to −12%) but increased in men (+12% to +23%), respectively, relative to SIT ( P <0.05). No differences in average norepinephrine were observed. Morning exercise reduces BP during a period of 8 hours in older overweight/obese adults compared with prolonged sitting. Combining exercise with regular breaks in sitting may be of more benefit for lowering BP in women than in men. Clinical Trial Registration— URL: https://www.anzctr.org.au . Unique identifier: ACTRN12614000737639.
Signaling through β-adrenergic receptors drives cancer progression and β-blockers are being evaluated as a novel therapeutic strategy to prevent metastasis. Orthotopic mouse models of breast cancer show that β-adrenergic signaling induced by chronic stress accelerates metastasis, and that β2-adrenergic receptors on tumor cells are critical for this. Endogenous catecholamines are released during chronic stress: norepinephrine from the adrenal medulla and sympathetic nerves, and epinephrine from the adrenal medulla. β2-adrenergic receptors are much more sensitive to epinephrine than to norepinephrine. To determine if epinephrine is necessary in the effects of stress on cancer progression, we used a denervation strategy to eliminate circulating epinephrine, and quantified the effect on metastasis. Using both human xenograft and immune-intact murine models of breast cancer, we show that circulating epinephrine is dispensable for the effects of chronic stress on cancer progression. Measured levels of circulating norepinephrine were sufficiently low that they were unlikely to influence β2-adrenergic signaling, suggesting a possible role for norepinephrine release from sympathetic nerve terminals.
Schlager mice (BPH/2J) are hypertensive due to a greater contribution of the sympathetic nervous system (SNS) and renin-angiotensin system (RAS). The kidneys of BPH/2J are hyper-innervated suggesting renal nerves may contribute to the hypertension. We therefore determined the effect of bilateral renal denervation (RD) on hypertension in BPH/2J. Mean arterial pressure (MAP) was measured by radiotelemetry before and for 3 weeks after RD in BPH/2J and BPN/3J. The effects of pentolinium and enalaprilat were examined to determine the contribution of the SNS and RAS, respectively. After 3 weeks, MAP was −10.9 ± 2.1 mmHg lower in RD BPH/2J compared to baseline and −2.1 ± 2.2 mmHg in sham BPH/2J (P < 0.001, n = 8–10). RD had no effect in BPN/3J (P > 0.1). The depressor response to pentolinium was greater in BPH/2J than BPN/3J, but in both cases the response in RD mice was similar to sham. Enalaprilat decreased MAP more in RD BPH/2J compared to sham (−12 vs −3 mmHg, P < 0.001) but had no effect in BPN/3J. RD reduced renal noradrenaline in both strains but more so in BPH/2J. RD reduced renin mRNA and protein, but not plasma renin in BPH/2J to levels comparable with BPN/3J mice. We conclude that renal nerves contribute to hypertension in BPH mice as RD induced a sustained fall in MAP, which was associated with a reduction of intrarenal renin expression. The lack of inhibition of the depressor effects of pentolinium and enalaprilat by RD suggests that vasoconstrictor effects of the SNS or RAS are not involved.
Background/Purpose: Sympathetic nervous system activation in obesity is associated with impaired cardiovascular and metabolic function. Animal studies have shown a direct link between sympathetic nervous activation and bone health but little is known about this link in humans. This study examined whether sympathetic activation may impact bone health in overweight adults. Methods: This cross sectional study included 96 overweight or obese middle-aged adults (51 males, mean body mass index: 32.8 kg/m(2), mean age: 55.3 years). Multivariate linear regression models evaluated associations between whole body and leg bone mineral density (BMD) and bone mineral content (BMC) derived from dual energy X-ray absorptiometry and muscle sympathetic nervous system activity (MSNA) measured by micro-neurography. Results: Older age, male sex and higher weight were associated with higher leg and body BMC and BMD. After adjustment for age, sex and weight, MSNA was significantly inversely associated with total BMC (p = 0.012) and with leg BMC (p < 0.01) but was not associated with either total or leg BMD (p = 0.159 and p = 0.063 respectively). When the analysis was sex specific, the relationships between MSNA and total and leg BMC were only significant in males. Conclusions: Our study indicates that in middle aged overweight or obese males, sympathetic activation may have a deleterious effect on bone mineral content.
cerns and Issues’ framework to facilitate group discussion and determine what was working well and what could be improved. Together the participants established key themes and identified appropriate ways forward. Results: 20 focus groups were conducted with 172 clinicians across all pilot sites in November. Commonly identified Claims included; the ease of identifying trends, the use of colours to identify abnormal parameters and being able to view all the observations on the one page. For the BSPN chart the incorporation of the Newborn Risk Assessment section was viewed positively. Key Concerns related to; the increments for recording temperature, documenting desaturation/bradycardic episodes and lack of ability to interpret observations in relation to feeding. Duplication of documentation and compliance with escalation processes were additional concerns. Conclusion: User feedback via focus groups has been a crucial aspect of the evaluation. Findings will inform changes to chart design, ongoing education and implementation strategies in preparation for a planned state-wide roll out in 2017.
Background: A diet rich in fat, in particular saturated fat (SF), may be linked to cardiovascular disease development, possibly due to a detrimental effect of fat on endothelial function (EF). Objective: We aimed to determine whether the habitual SF intake [as a ratio to total fat (the sum of saturated, polyunsaturated, and monounsaturated fat)] might influence endothelial function in young, overweight but otherwise healthy adults. Design: Sixty-nine young adults (49 males, mean age: 23 ± 1 years, mean BMI: 29.1 ± 0.8 kg/m2) were classified into three tertiles according to their habitual SF intake consumption (low SF: <39%, medium SF 39.1-43.7%, and high SF: >43.7% of total fat). Endothelial function was assessed using digital amplitude tonometry. Results: The three groups of individuals were comparable for total energy intake and calories from: fat, protein, and carbohydrates. There was no difference in anthropometric and hemodynamic variables among the groups. Those in the high SF group presented with impaired endothelial function [reactive hyperemia index (RHI): high SF: 1.60 ± 0.08 compared to 2.23 ± 0.16 in the medium SF and 2.12 ± 0.14 in the low SF group, P < 0.01]. Regression analysis, including gender, age, ethnicity, body mass index indicated that the ratio of SF to total fat was an independent predictor of the RHI (P < 0.05). Conclusion: The habitual consumption of a diet high in SF in relation to polyunsaturated and monounsaturated fat was strongly associated with impaired endothelial function in young overweight adults, potentially contributing to increased risk of developing cardiovascular disease.
Background:Asian subjects are at increased cardio-metabolic risk at comparatively lower body mass index (BMI) compared with white subjects. Sympathetic nervous system activation and dyslipidemia, both characteristics of increased adiposity, appear to be related. We therefore analyzed the association of muscle sympathetic nerve activity (MSNA) with the plasma lipidomic profile in young adult Asian and white subjects.Methods:Blood samples were collected from 101 participants of either Asian or white background (age, 18 to 30 years; BMI, 28.1 ± 5.9 kg/m2). Lipids were extracted from plasma and analyzed using electrospray ionization-tandem mass spectrometry. MSNA was quantified using microneurography. The association of MSNA and obesity with lipid species was examined using linear regression analysis.Results:The plasma concentrations of total dihydroceramide, ceramide, GM3 ganglioside, lysoalkylphosphatidylcholine, alkenylphosphatidylethanolamine, and lysophosphatidylinositol were elevated in the Asian subjects relative to the white subjects. After adjustment for confounders, diacylglycerols and triacylglycerols, cholesterol esters, phosphatidylinositols, phosphatidylethanolamines, and phosphatidylglycerols bore significant associations with MSNA but only in the Asian subjects. These associations remained significant after further adjustment for the participants' degree of insulin resistance and appeared not to be related to differences in diet macronutrient content between groups.Conclusions:The lipidomic profile differs between Asian and white subjects. There exists a strong relationship between certain lipid species and MSNA. The association is stronger in Asian subjects, despite their lower BMI. This study demonstrates an association between circulating lipids and central sympathetic outflow. Whether the stronger association between the lipid profile and sympathetic activation underpins the apparent greater risk posed by increased adiposity in Asian individuals merits further attention.
Background: Neck circumference (NC) is a predictor of cardiometabolic risk. The objective of this study was to explore the relationship of NC to muscle sympathetic nerve activity (MSNA) within an overweight and obese population. Methods: The study design was a retrospective cross-sectional analysis. Un-medicated persons (72 men, 53 postmenopausal women) aged 56 ± 1 years (mean ± SEM) with body mass index (BMI) 32.8 ± 0.4 kg/m2, were studied. NC was measured together with traditional anthropometric measures, supine blood pressure, fasting blood lipids, insulin, and glucose. Insulin sensitivity was assessed by homeostasis model (HOMA-IR) and Matsuda Insulin Sensitivity Index (ISI) derived from 75-g oral glucose tolerance test. Resting multiunit MSNA was recorded by microneurography in the peroneal nerve and expressed as burst frequency and burst incidence. Results: Men within the highest tertile of NC had significantly higher fasting and post-glucose plasma insulin levels (insulin AUC0-120), HOMA-IR, non-esterified fatty acids, MSNA (45 ± 2 vs. 36 ± 2 bursts per min; 69 ± 3 vs. 58 ± 3 bursts per 100 hb) and heart rate, and lower Matsuda ISI compared to men in the lowest tertile (P all <0.05). In stepwise regression analyses, NC alone explained 12%, and together with insulin AUC0-120 it accounted for 22%, of the variance in MSNA in men. In women, NC was associated with anthropometric measures but not with MSNA or metabolic indices. Conclusions: Among overweight and obese men, NC was independently associated with elevated MSNA and hyperinsulinemia, and thus may be relevant to cardiometabolic risk prediction. The biological basis of gender differences merits further elucidation.
This study tested the hypothesis that varying degrees of hemodynamic fluctuations seen after birth following immediate cord clamping were related to development of asphyxia with longer cord clamp-to-ventilation intervals, resulting in higher perinatal circulating levels of the catecholamines norepinephrine (NE) and epinephrine (Epi), and thus increased heart rate, blood pressures, and cardiac contractility after birth. Anesthetized preterm fetal lambs were instrumented with 1) aortic (AoT) and pulmonary trunk (PT) micromanometers to obtain pressures and the maximal rate of pressure rise (dP/dtmax) as a surrogate measure of ventricular contractility, and 2) an AoT catheter to obtain samples for blood gas and catecholamine analyses. After delivery, immediate cord clamping was followed by ventilation ∼40 s (n = 7), ∼60 s (n = 8), ∼90 s (n = 9), or ∼120 s later (n = 8), with frequent blood sampling performed before and after ventilation. AoT O2 content fell rapidly after immediate cord clamping (P < 0.001), with an asphyxial state evident at ≥60 s. Plasma NE and Epi levels increased progressively with longer cord clamp-to-ventilation intervals, with an exponential relation between falling AoT O2 content and rising catecholamines (R2 = 0.64-0.67). Elevated circulating catecholamines persisted for some minutes after ventilation onset, with postbirth surges in heart rate, AoT and PT pressures, and AoT and PT dP/dtmax linearly related to loge of catecholamine levels (R2 = 0.41-0.54, all P < 0.001). These findings suggest that 1) a greater degree of asphyxia-induced sympathoadrenal activation (reflected in elevated circulating catecholamine levels) occurs with longer intervals between immediate cord clamping and subsequent ventilation, and 2) this activation is a major determinant of hemodynamic fluctuations evident with birth.
Objective Because sympathetic nervous system activity plays a detrimental role in metabolic and cardiovascular health, this study compared the effects of a centrally acting sympatholytic agent, the effects of a weight loss (WL) program using a low‐calorie diet, and the effects of a combination of both. Methods Young (18‐30 years) male subjects with overweight (BMI > 25 kg/m 2 ) were allocated to a WL program ( n = 10), a moxonidine treatment course (M; n = 10, 0.4 mg/d), a combination of both (WL + M; n = 11), or to a control (C) group ( n = 6) for 6 months. Muscle sympathetic nerve activity (MSNA), endothelial function, renal function (Cockcroft‐Gault formula), and the metabolic profile were assessed before and after intervention. Results WL occurred in the WL and WL + M groups (−7.6 ± 1.9 kg, P < 0.001 in both). MSNA and systolic blood pressure decreased similarly in the WL, M, and WL + M groups (by ∼10 bursts/min, P < 0.001, and by ∼9 mm Hg, P < 0.05). All other parameters for the WL, C, and M groups remained unchanged. In the WL + M group, decreased total cholesterol (−0.78 ± 0.23 mmol/L, P < 0.001), decreased low‐density lipoprotein cholesterol (−0.49 ± 0.16 mmol/L, P < 0.01), decreased insulin (−6.5 ± 2.8 mmol/L, P < 0.05), and attenuated glomerular hyperfiltration (−19 ± 5 mL/min, P < 0.01) occurred. Conclusions The combination of moxonidine with a WL program has beneficial effects on aspects of the metabolic profile and end organ damage in young males with overweight.
sion criteria. The correlation between body mass index and ideal weight gain was analyzed using Pearson test. Results: Based on BMI, 10 subjects (9%) were classified as underweight, 48 subjects (43.2%) were classified as normoweight, 16 subjects (14.4%) were classified as overweight, and 37 subjects (33.3%) were classified as obese. Pearson correlation test showed that there is a significant correlation between BMI before pregnancy and weight gain during pregnancy (p <0.001). Conclusion: Most of women in Pasar Rebo PHC did not reach the ideal weight gain during pregnancy. The underweight and normoweight groups were more likely to have inadequate weight gain compared to overweight and obese groups. The achievement of the ideal weight gain during pregnancy has a weak correlation with BMI before pregnancy.