Development of a Hypercoagulable-Hypofibrinolytic State Early After Spinal Cord Injury

OBJECTIVES

To determine whether spinal cord injury (SCI) is associated with adverse changes in coagulation and fibrinolytic factors that underlie thrombogenesis and contribute to atherothrombotic events such as myocardial infarctions (MIs) and strokes.

DESIGN

Cross-sectional study.

SETTING

Neurorehabilitation hospital and general community.

PARTICIPANTS

Thirty young and middle-aged (20-58 years) adults (N=30) were studied: 14 non-injured community dwelling adults. (11M/4F) and 16 with subacute tetraplegic motor complete SCI during initial inpatient rehabilitation (13M/3F; time since injury: 11.8±5.3 wk).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Circulating markers of coagulation [von Willebrand factor (vWf) and factors VII, VIII, and X], the fibrinolytic system [tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor-1 (PAI-1) antigen and activity], and fibrin formation (D-dimer) were determined by enzyme immunoassay.

RESULTS

Thirty young and middle-aged (20-58 years) adults were studied: 14 non-injured (11M/4F) and 16 with subacute tetraplegic motor complete SCI (13M/3F; time since injury: range 4-25 wk). Circulating levels of coagulation factors VII, VIII, and X were significantly higher (∼20%-45%; P<.05) in the adults with SCI than non-injured adults, whereas vWf was similar between groups. Fibrinolytic markers were adversely disrupted with SCI with t-PA antigen, PAI-1 antigen and PAI-1 activity were markedly higher (∼50%-800%; P<.05) in adults with SCI compared with non-injured adults. The molar concentration ratio of active t-PA to PAI-1 was significantly higher (∼350%) in adults with SCI. Concordant with coagulation cascade activation and fibrinolytic system inhibition, D-dimer concentrations were markedly ∼70% higher (P<.05) in adults with SCI compared with non-injured adults.

CONCLUSIONS

Subacute tetraplegic motor complete SCI is associated with a prothrombotic hemostatic profile. Adverse changes in the coagulation cascade and fibrinolytic system appear to occur early after injury and may contribute to the increased atherothrombotic risk in adults living with SCI.

Ascorbic acid prevents stress-induced hypercoagulability in overweight and obese individuals

Ascorbic acid (AA) may contribute to restoring hemostatic balance after mental stress (MS) in overweight/obese adults. We aimed to determine the effects of AA administration on hemostatic responses to MS in overweight/obese men. Fourteen overweight/obesity men (27 ± 7 years; BMI: 29.7 ± 2.6 kg m-2) performed the Stroop color-word stress task for 5 min after non-simultaneous infusion of placebo (PL, 0.9% NaCl) and AA (3 g). Blood was collected at baseline, during MS, and 60 min after MS to measure: activated partial thromboplastin time, prothrombin time, and fibrinogen concentration, by coagulometer; platelet-derived microvesicles (PMV, mv/μL), by flow cytometry; nitrite (μM), by chemiluminescence. In PL session, MS led to decreases in PTs (stress, p = 0.03; 60 min, p < 0.001), PT-INR (stress, p < 0.001; 60 min, p < 0.01), aPTTs (60 min, p = 0.03), aPTT ratio (60 min, p = 0.04) and fibrinogen (60 min, p = 0.04), while increased PT activity (60 min, p = 0.01) when compared to baseline. Furthermore, AA increased PTs (60 min, p < 0.001), PT-INR (60 min, p = 0.03) and decreased PT activity (60 min, p < 0.001) and fibrinogen (stress, p = 0.04) when compared to PL. Nitrite was increased in response to stress during AA session (p < 0.001 vs PL). There was no difference in PMV. Ascorbic acid prevented the impaired hemostatic profile and improved nitrite response to stress in the overweight and obese adults.

Effects of circulating endothelial microvesicles isolated from adults with obesity on endothelial cell inflammation, apoptosis, and nitric oxide production

Circulating endothelial cell-derived microvesicles (EMVs) have been shown to be elevated with obesity and associated with endothelial dysfunction; however, their direct effect on endothelial cells is unknown. The experimental aim of this study was to determine the effect of EMVs isolated from adults with obesity on endothelial cell inflammation, apoptosis, and nitric oxide (NO) production. EMVs (CD144+ microvesicles) were identified, enumerated, and isolated from plasma by flow cytometry from 24 sedentary adults: 12 normal-weight adults [8 M/4 F; age: 55 ± 6 yr; body mass index (BMI): 24.3 ± 0.7 kg/m2; EMV: 144 ± 53 EMVs/µL] and 12 adults with obesity (6 M/6 F; 59 ± 7 yr; BMI: 31.0 ± 1.1 kg/m2; EMV: 245 ± 89 EMVs/µL). Human umbilical vein endothelial cells were cultured and treated with EMVs from either normal-weight adults or adults with obesity. EMVs from obese adults induced significantly higher release of interleukin (IL)-6 (108.2 ± 7.7 vs. 90.9 ± 10.0 pg/mL) and IL-8 (75.4 ± 9.8 vs. 59.5 ± 11.5 pg/mL) from endothelial cells vs. EMVs from normal-weight adults, concordant with greater intracellular expression of phosphorylated NF-κB p65 (Ser536; active NF-κB) [145.0 ± 34.1 vs. 114.5 ± 30.4 arbitrary units (AU)]. Expression of phosphorylated p38-MAPK (15.4 ± 5.7 vs. 9.2 ± 2.5 AU) and active caspase-3 (168.2 ± 65.5 vs. 107.8 ± 40.5 AU), markers of cell apoptosis, was higher in cells treated with obesity-related EMVs. Phosphorylated endothelial nitric oxide synthase (eNOS) (Ser1177) expression (23.5 ± 7.2 vs. 34.7 ± 9.7 AU) and NO production (6.9 ± 1.4 vs. 8.7 ± 0.7 µmol/L) were significantly lower in the cells treated with EMVs from obese adults. These data indicate that circulating EMVs from adults with obesity promote a proinflammatory, proapoptotic, and NO-compromised endothelial phenotype. Circulating EMVs are a potential mediator of obesity-related endothelial dysfunction.NEW & NOTEWORTHY In the present study, we determined the effect of circulating endothelial cell-derived microvesicles (EMVs) isolated from adults with obesity on endothelial cell inflammation, apoptosis, and nitric oxide (NO) production in vitro. Circulating EMVs harvested from adults with obesity promoted a proinflammatory, proapoptotic, and NO-compromised endothelial phenotype. Elevated circulating EMVs in adults with obesity, independent of other cardiometabolic risk factors, are a potential novel systemic mediator of obesity-related endothelial dysfunction and vascular risk.

Global REACH 2018: High Altitude-Related Circulating Extracellular Microvesicles Promote a Proinflammatory Endothelial Phenotype In Vitro

Brewster, L. Madden, Anthony R. Bain, Vinicius P. Garcia, Noah M. DeSouza, Michael M. Tymko, Jared J. Greiner, and Philip N. Ainslie. Global REACH 2018: high altitude-related circulating extracellular microvesicles promote a proinflammatory endothelial phenotype in vitro. High Alt Med Biol. 24:223-229, 2023. Introduction: Ascent to high altitude (HA) can induce vascular dysfunction by promoting a proinflammatory endothelial phenotype. Circulating microvesicles (MVs) can mediate the vascular endothelium and inflammation. It is unclear whether HA-related MVs are associated with endothelial inflammation. Objectives: We tested the hypothesis that MVs derived from ascent to HA induce a proinflammatory endothelial phenotype. Methods: Ten healthy adults (8 M/2 F; age: 28 ± 2 years) residing at sea level (SL) were studied before and 4-6 days after rapid ascent to HA (4,300 m). MVs were isolated and enumerated from plasma by centrifugation and flow cytometry. Human umbilical vein endothelial cells were treated with MVs collected from each subject at SL (MV-SL) and at HA (MV-HA). Results: Circulating MV number significantly increased at HA (26,637 ± 3,315 vs. 19,388 ± 1,699). Although intracellular expression of total nuclear factor kappa beta (NF-κB; 83.4 ± 6.7 arbitrary units [AU] vs. 90.2 ± 6.9 AU) was not affected, MV-HA resulted in ∼55% higher (p < 0.05) active NF-κB (129.6 ± 19.8 AU vs. 90.7 ± 10.5 AU) expression compared with MV-SL. In addition, MV-HA induced higher interleukin (IL)-6 (63.9 ± 3.9 pg/ml vs. 53.3 ± 3.6 pg/ml) and IL-8 (140.2 ± 3.6 pg/ml vs. 120.7 ± 3.8 pg/ml) release compared with MV-SL, which was blunted with NF-κB blockade. Conclusions: Circulating extracellular MVs increase at HA and induce endothelial inflammation, potentially contributing to altitude-related vascular dysfunction.

Endothelial derived extracellular vesicles associated with electronic cigarette use impair cerebral microvascular cell function

The aim of this study was to determine the effect of circulating endothelial cell-derived microvesicles (EMVs) isolated from e-cigarette users on human cerebral microvascular endothelial cells (hCMECs) nitric oxide (NO) and endothelin (ET)-1 production and tissue-type plasminogen activator (t-PA) release. Circulating EMVs (CD144-PE) were isolated (flow cytometry) from 27 young adults (19-25 yr): 10 non-smokers (6M/4F), 10 e-cigarette users (6M/4F) and 7 tobacco cigarette smokers (4M/3F). hCMECs were cultured and treated with isolated EMVs for 24hr. EMVs from e-cigarette users and cigarette smokers induced significantly higher expression of p-eNOS (Thr495)(28.4±4.6 vs 29.1±2.8 vs 22.9±3.8 AU), Big ET-1 (138.8±19.0 vs 141.7±19.1 vs 90.3±18.8 AU) and ECE (107.6±10.1 and 113.5±11.8 vs 86.5±13.2 AU) and significantly lower expression of p-eNOS (Ser1177) (7.4±1.7 vs 6.5±0.5 vs 9.7±1.6 AU) in hCMECs than EMVs from non-smokers. NO production was significantly lower and ET-1 production significantly higher in hCMECs treated with EMVs from e-cigarette (5.7±0.8 μmol/L; 33.1±2.9 pg/mL) and cigarette smokers (6.3±0.7 μmol/L; 32.1±3.9 pg/mL) than EMVs from non-smokers (7.6±1.2 μmol/L; 27.9± 3.1 pg/mL). t-PA release in response to thrombin was significantly lower in hCMECs treated with EMVs from e-cigarette users (from 38.8±6.3 to 37.4+8.3 pg/mL) and cigarette smokers (31.5±5.5 to 34.6±8.4 pg/mL) than EMVs from non-smokers (38.9±4.3 to 48.4±7.9 pg/mL). There were no significant differences in NO, ET-1 or t-PA protein expression or production in hCMECs treated with EMVs from e-cigarette users and smokers. Circulating EMVs associated with e-cigarette use adversely affects brain microvascular endothelial cells and may contribute to reported cerebrovascular dysfunction with e-cigarette use.

Endothelial-derived extracellular vesicles from obese/hypertensive adults increase factors associated with hypertrophy and fibrosis in cardiomyocytes

Obesity and hypertension, independently and combined, are associated with increased risk of heart failure and heart failure-related morbidity and mortality. Interest in circulating endothelial cell-derived microvesicles (EMVs) has intensified because of their involvement in the development and progression of endothelial dysfunction, atherosclerosis, and cardiomyopathy. The experimental aim of this study was to determine, in vitro, the effects of EMVs isolated from obese/hypertensive adults on key proteins regulating cardiomyocyte hypertrophy [cardiac troponin T (cTnT), α-actinin, nuclear factor-kB (NF-kB)] and fibrosis [transforming growth factor (TGF)-β, collagen1-α1], as well as endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) production. EMVs (CD144+ microvesicles) were isolated from plasma by flow cytometry in 12 normal weight/normotensive [8 males/4 females; age: 56 ± 5 yr; body mass index (BMI): 23.3 ± 2.0 kg/m2; blood pressure (BP): 117/74 ± 4/5 mmHg] and 12 obese/hypertensive (8 males/4 females; 57 ± 5 yr; 31.7 ± 1.8 kg/m2; 138/83 ± 8/7 mmHg) adults. Human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were cultured and treated with EMVs from either normal weight/normotensive or obese/hypertensive adults for 24 h. Expression of cTnT (64.1 ± 13.9 vs. 29.5 ± 7.8 AU), α-actinin (66.0 ± 14.7 vs. 36.2 ± 10.3 AU), NF-kB (166.3 ± 13.3 vs. 149.5 ± 8.8 AU), phosphorylated-NF-kB (226.1 ± 25.2 vs. 179.1 ± 25.5 AU), and TGF-β (62.1 ± 13.3 vs. 23.5 ± 8.8 AU) were significantly higher and eNOS activation (16.4 ± 4.3 vs. 24.8 ± 3.7 AU) and nitric oxide production (6.8 ± 1.2 vs. 9.6 ± 1.3 µmol/L) were significantly lower in iPSC-CMs treated with EMVs from obese/hypertensive compared with normal weight/normotensive adults. These data indicate that EMVs from obese/hypertensive adults induce a cardiomyocyte phenotype prone to hypertrophy, fibrosis, and reduced nitric oxide production, central factors associated with heart failure risk and development.NEW & NOTEWORTHY In the present study we determined the effect of endothelial microvesicles (EMVs) isolated from obese/hypertensive adults on mediators of cardiomyocyte hypertrophy [cardiac troponin T (cTnT), α-actinin, nuclear factor-kB (NF-kB)] and fibrosis [transforming growth factor (TGF-β), collagen1-α1] as well as endothelial nitric oxide synthase (eNOS) expression and NO production. EMVs from obese/hypertensive induced significantly higher expression of hypertrophic (cTnT, α-actinin, NF-kB) and fibrotic (TGF-β) proteins as well as significantly lower eNOS activation and NO production in cardiomyocytes than EMVs from normal weight/normotensive adults. EMVs are a potential mediating factor in the increased risk of cardiomyopathy and heart failure with obesity/hypertension.

Differential Expression of Vascular-Related MicroRNA in Circulating Endothelial Microvesicles in Adults With Spinal Cord Injury: A Pilot Study

Background

Spinal cord injury (SCI) is associated with an increased risk and prevalence of cardiopulmonary and cerebrovascular disease-related morbidity and mortality. The factors that initiate, promote, and accelerate vascular diseases and events in SCI are poorly understood. Clinical interest in circulating endothelial cell-derived microvesicles (EMVs) and their microRNA (miRNA) cargo has intensified due to their involvement in endothelial dysfunction, atherosclerosis, and cerebrovascular events.

Objectives

The aim of this study was to determine whether a subset of vascular-related miRNAs is differentially expressed in EMVs isolated from adults with SCI.

Methods

We assessed eight adults with tetraplegia (7 male/1 female; age: 46±4 years; time since injury: 26±5 years) and eight uninjured (6 male/2 female; age: 39±3 years). Circulating EMVs were isolated, enumerated, and collected from plasma by flow cytometry. The expression of vascular-related miRNAs in EMVs was assessed by RT-PCR.

Results

Circulating EMV levels were significantly higher (~130%) in adults with SCI compared with uninjured adults. The expression profile of miRNAs in EMVs from adults with SCI were significantly different than uninjured adults and were pathologic in nature. Expression of miR-126, miR-132, and miR-Let-7a were lower (~100-150%; p < .05), whereas miR-30a, miR-145, miR-155, and miR-216 were higher (~125-450%; p < .05) in EMVs from adults with SCI.

Conclusion

This study is the first examination of EMV miRNA cargo in adults with SCI. The cargo signature of vascular-related miRNAs studied reflects a pathogenic EMV phenotype prone to induce inflammation, atherosclerosis, and vascular dysfunction. EMVs and their miRNA cargo represent a novel biomarker of vascular risk and a potential target for intervention to alleviate vascular-related disease after SCI.

AT1R blocker prevents mental stress induced retrograde blood flow in overweight/obese men

The main goal was to determine the impact of mental stress (MS) on blood flow regulation in overweight/obese men. Fourteen overweight/obese men (27 ± 7 years; 29.8 ± 2.6 kg/m² ) participated in two randomized experimental sessions with oral administration of the AT1R blocker Olmesartan (40 mg; AT1RB) or placebo (PL). After 2 h, a 5-min acute MS session (Stroop Color Word Test) was administered. Blood flow was assessed at baseline and during the first 3 min of MS by vascular ultrasound in the brachial artery. Blood was collected before (baseline) and during mental stress (MS) for measurement of nitrite (chemiluminescence) and endothelin-1 (ELISA kit). The AT1R blocker was able to reverse the MS responses observed in the placebo session for retrograde flow (p < 0.01), retrograde SR (p < 0.01) and oscillatory shear index (p = 0.01). Regarding vasoactive substances, no differences were observed in ET-1 (p > 0.05) responses to MS between experimental sessions. However, for nitrite responses, the administration of the AT1R blocker was able to increase circulating levels of NO (p = 0.03) Blockade of AT1R appears to prevent the decrease in endothelial function by reducing low shear stress and maintaining the vasoactive substances balance after MS in overweight/obese men.

Mental stress induces endothelial dysfunction by AT1R-mediated redox imbalance in overweight/obese men

The main goal of this study was to determine whether oxidative imbalance mediated by AT1 receptor (AT1R) is responsible for deleterious endothelial responses to mental stress (MS) in overweight/obese class I men. Fifteen overweight/obese men (27±7 years old; 29.8±2.6 kg/m2) participated in three randomized experimental sessions with oral administration of the AT1R blocker olmesartan (40 mg; AT1R blockade) or ascorbic acid (AA; 3g) infusion or placebo [both intravenously (0.9% NaCl) and orally]. After two hours, endothelial function was determined by flow-mediated dilation (FMD) before (baseline), 30 min (30MS), and 60 min (60MS) after a five-minute acute MS session (Stroop Color Word Test). Blood was collected before (baseline), during MS, and 60 min after MS for redox homeostasis profiling: lipid peroxidation (TBARS; thiobarbituric acid reactive species), protein carbonylation, and catalase activity by colorimetry and superoxide dismutase (SOD) activity by an ELISA kit. At the placebo session, FMD significantly decreased 30MS (P=0.05). When compared to baseline, TBARS (P<0.02), protein carbonylation (P<0.01), catalase (P<0.01), and SOD (P<0.01) increased during the placebo session. During AT1R blockade, FMD increased 30 min after MS (P=0.01 vs baseline; P<0.01 vs placebo), while AA infusion increased FMD only 60 min after MS. No differences were observed during MS with the AT1R blockade and AA regarding TBARS, protein carbonylation, catalase, and SOD. AT1R-mediated redox imbalances played an important role in endothelial dysfunction to mental stress.

Abstract P004: Chronic Nebivolol And Metoprolol Treatment Reduce Circulating Endothelial Cell-Derived Microvesicles In Adults With Hypertension

Nebivolol and metoprolol are effective blood pressure medications that also reduce risk of cardiovascular and cerebrovascular events. Endothelial cell-derived microvesicles (EMVs) are small anucleoid, extracellular vesicles released in response to a myriad of stimuli that trigger cell activation or apoptosis. Clinical interest in EMVs has increased due, in part, to their role in the development and progression of cardiovascular and cerebrovascular disease as well as their prognostic value. Circulating EMVs are elevated with hypertension and contribute to vascular dysfunction. The aim of this study was to determine the independent effects of nebivolol and metoprolol treatment on circulating EMVs in adult humans with hypertension. Thirty-eight middle-aged adults with elevated blood pressure completed a 3-month double-blind, randomized, placebo-controlled trial: 14 received nebivolol (N: 8M/6F; 5 mg/d; age: 58±2 yr; BP: 142/86±2/2 mmHg), 15 received metoprolol succinate (M: 9M/6F; 100 mg/d; 57±2 yr; 139/87±2/2 mmHg), and 9 received placebo (P: 5M/4F; 1 gelatin capsule/d; 55±3 yr; 136/84±2/2 mmHg). Blood pressure was lowered (P<0.05) to a similar extent by both N (124/76 + 3/2 mmHg) and M (125/79 + 3/2 mmHg) but unchanged by P (133/80 + 3/2 mmHg). EMV phenotype was determined using markers indicative of endothelial activation (CD62e + ) or apoptosis (CD31 + /CD42b - ) by flow cytometry. Circulating activation- and apoptosis-derived EMVs were significantly lower (~25%) after N (activation-EMVs: 68±7 to 48±6 EMV/μL; apoptosis-EMVs: 129±2 to 103±9 EMV/μl) and M (activation-EMVs: 57±5 to 39±3 EMVs/μL; apoptosis-EMVs: 125±4 to 96±9 EMV/μL) treatment. Placebo had no significant effect on EMVs (activation-EMVs: 61±7 to 57±6 EMV/μL; apoptosis-EMVs: 131 + 3 to 124 + 8 EMV/μL). There was no significant correlation between the reduction in either EMV phenotype and changes in blood pressure in the N or M group. These results demonstrate that both N and M treatment reduce circulating EMVs, and the reduction appears to be independent of changes in blood pressure. Lower circulating EMVs may contribute to the reduced risk of cardiovascular and cerebrovascular events associated with chronic N and M therapy.

Abstract 048: Extracellular Endothelial Microvesicles Causative Agents In Hypertension-related Endothelial Dysfunction

We have previously demonstrated that endothelial cell-derived microvesicles (EMVs) are elevated with hypertension and are associated with endothelial dysfunction. However, it is unknown whether EMVs play a causative role in blood pressure-related endothelial dysfunction. The experimental aim of this study was to determine the effects of EMVs isolated from hypertensive adults on endothelial cell inflammation, apoptosis and nitric oxide (NO) production. Twenty middle-aged adults were studied: 10 normotensive (NT: 8M/2F; 57 + 2 yr; BP: 113/71 + 2/2 mmHg; EMVs: 64 + 10 EMV/μL) and 10 hypertensive (HT: 6M/4F; 56 + 2 yr; 137/82 + 2/2 mmHg; 115 + 17 EMV/μL). All subjects were sedentary, non-smokers, non-medicated and free of overt cardiometabolic diseases. EMVs (CD144+) were identified, sorted and collected from plasma by flow cytometry. Human umbilical vein endothelial cells were cultured and treated with EMVs from either NT or HT adults. EMVs from HT induced significantly greater release of interleukin (IL)-6 (38.9±1.5 vs 31.5±0.9 pg/mL) and IL-8 (38.1±2.7 vs 30.3±1.8 pg/mL) compared with EMVs from NT. Concordantly, HT-related EMVs induced ~25% higher (P<0.05) expression of phosphorylated-NF-kB p65 (Ser536; active NF-kB) (168.5 + 12.1 vs 136.8 + 7.0 AU). HT EMVs induced significantly higher activation of the apoptotic proteins p38-MAPK (26.0 + 4.5 vs 12.4 + 1.2 AU) and caspase-3 (243.1±36.7 vs 150.8±17.0 AU) than NT EMVs. Although total eNOS expression was not significantly altered; active eNOS (pSer1177) (221.02 + 34.8 vs 331.5 + 30.4 AU) and, in turn, NO production (6.2 + 0.4 vs 9.4 + 0.6 υmol/L) were significantly lower (~30%) in the cells treated with EMVs from HT adults. Increased inflammation, apoptosis susceptibility and decreased NO production are central features of endothelial dysfunction. Circulating EMVs represent both a biomarker and mediator of endothelial dysfunction with hypertension.

Abstract P127: Systemic Immune-Inflammatory Index (SII) In Hypertensive Adults

Aside from age, hypertension is the most predominant cardiovascular disease risk factor worldwide. In the United States, ~45% of the adult population have blood pressure higher than 130/80 mmHg. Hypertension is associated with increased risk of myocardial infarction, heart failure, stroke and vascular disease. Systemic immune-inflammation index (SII) is a novel biomarker of systemic inflammation and immunity. Clinical interest in SII has intensified due to its association with major cardiovascular events and prognostic value in cardiovascular outcomes. Indeed, the index has been shown to be a strong prognostic marker for coronary artery disease, heart failure, cardiac death and stroke. It is currently unknown whether SII is elevated in adults with elevated blood pressure. We tested the hypothesis that hypertension is associated with an elevated SII, independent of other cardiometabolic risk factors and/or disease. Fifty-six adults (age range: 43 to 66 years) were studied: 22 normotensive (NT: 10M/12F; age 57 + 1 yr; BMI: 27.7 + 1.0 kg/m 2 ; BP: 120/75 + 1/1 mmHg) and 34 hypertensive (HT: 23M/11F; age 57 + 1 yr; 28.4 + 0.6 kg/m 2 ; BP 140/85 + 1/1 mmHg). All subjects were sedentary, non-smokers, normolipidemic, normoglycemic, non-medicated, and free of overt cardiometabolic diseases. SII was calculated as total peripheral platelets count x neutrophil-to-lymphocyte ratio. SII was significantly higher (~20%) in the HT (479.6 + 25.0) vs NT (402.5 + 27.8) group. There was no significant sex by blood pressure interaction with SII. SII was similar and equally elevated in HT males (487.7 + 34.7) and females (462.7 + 28.7) than NT males (364.4 + 30.8) and females (425.9 + 39.9). SII was independently associated with systolic (r=0.30; P<0.05) and mean arterial (r=0.26; P<0.05) blood pressure; SII was not significantly associated with any other anthropometric, hemodynamic or metabolic variable. Hypertension is associated with elevated SII indicative of greater systemic immune-inflammatory activation. Increased immune activation and inflammatory burden contribute not only to atherosclerosis but to progression of hypertension. Given the link between SII and poor prognosis, SII may aid in identifying high risk hypertensive groups.

Short isocapnic hyperoxia affects indices of vascular remodeling and intercellular adhesion molecules in healthy men

In preparation for tracheal intubation during induction of anesthesia, the patient may be ventilated with 100% oxygen. To investigate the impact of acute isocapnic hyperoxia on endothelial activation and vascular remodeling, ten healthy young men (24±3 years) were exposed to 5-min normoxia (21% O2) and 10-min hyperoxia trials (100% O2). During hyperoxia, intercellular adhesion molecules (ICAM-1) (hyperoxia: 4.16±0.85 vs normoxia: 3.51±0.84 ng/mL, P=0.04) and tissue inhibitor matrix metalloproteinase 1 (TIMP-1) (hyperoxia: 8.40±3.84 vs normoxia: 5.73±2.15 pg/mL, P=0.04) increased, whereas matrix metalloproteinase (MMP-9) activity (hyperoxia: 0.53±0.11 vs normoxia: 0.68±0.18 A.U., P=0.03) decreased compared to the normoxia trial. We concluded that even short exposure to 100% oxygen may affect endothelial activation and vascular remodeling.

Reactive oxygen species play a modulatory role in the hyperventilatory response to poikilocapnic hyperoxia in humans

KEY POINTS

The proposed mechanism for the increased ventilation in response to hyperoxia includes a reduced brain CO₂ -[H⁺ ] washout-induced central chemoreceptor stimulation that results from a decrease in cerebral perfusion and the weakening of the CO₂ affinity for haemoglobin. Nonetheless, hyperoxia also results in excessive brain reactive oxygen species (ROS) formation/accumulation, which hypothetically increases central respiratory drive and causes hyperventilation. We then quantified ventilation, cerebral perfusion/metabolism, arterial/internal jugular vein blood gases and oxidant/antioxidant biomarkers in response to hyperoxia during intravenous infusion of saline or ascorbic acid to determine whether excessive ROS production/accumulation contributes to the hyperoxia-induced hyperventilation in humans. Ascorbic acid infusion augmented the antioxidant defence levels, blunted ROS production/accumulation and minimized both the reduction in cerebral perfusion and the increase in ventilation observed during saline infusion. Hyperoxic hyperventilation seems to be mediated by central chemoreceptor stimulation provoked by the interaction between an excessive ROS production/accumulation and reduced brain CO₂ -[H⁺ ] washout.

ABSTRACT

The hypothetical mechanism for the increase in ventilation ( V ̇ E ) in response to hyperoxia (HX) includes central chemoreceptor stimulation via reduced CO₂ -[H⁺ ] washout. Nonetheless, hyperoxia disturbs redox homeostasis and raises the hypothesis that excessive brain reactive oxygen species (ROS) production/accumulation may increase the sensitivity to CO₂ or even solely activate the central chemoreceptors, resulting in hyperventilation. To determine the mechanism behind the HX-evoked increase in V ̇ E , 10 healthy men (24 ± 4 years) underwent 10 min trials of HX under saline and ascorbic acid infusion. V ̇ E , arterial and right internal right jugular vein (ijv) partial pressure for oxygen (PO₂ ) and CO₂ (PCO₂ ), pH, oxidant (8-isoprostane) and antioxidant (ascorbic acid) markers, as well as cerebral blood flow (CBF) (Duplex ultrasonography), were quantified at each hyperoxic trial. HX evoked an increase in arterial partial pressure for oxygen, followed by a hyperventilatory response, a reduction in CBF, an increase in arterial 8-isoprostane, and unchanged PijvCO₂ and ijv pH. Intravenous ascorbic acid infusion augmented the arterial antioxidant marker, blunted the increase in arterial 8-isoprostane and attenuated both the reduction in CBF and the HX-induced hyperventilation. Although ascorbic acid infusion resulted in a slight increase in PijvCO₂ and a substantial decrease in ijv pH, when compared with the saline bout, HX evoked a similar reduction and a paired increase in the trans-cerebral exchanges for PCO₂ and pH, respectively. These findings indicate that the poikilocapnic hyperoxic hyperventilation is likely mediated via the interaction of the acidic brain interstitial fluid and an increase in central chemoreceptor sensitivity to CO₂ , which, in turn, seems to be evoked by the excessive ROS production/accumulation.

Global REACH 2018: Influence of excessive erythrocytosis on coagulation and fibrinolytic factors in Andean highlanders

NEW FINDINGS

What is the central question of this study? Are coagulation and fibrinolytic factors disrupted in Andean highlanders with excessive erythrocytosis? What is the main finding and its importance? Excessive erythrocytosis is not associated with prothombotic disruptions in coagulation or the fibrinolytic system in Andean highlanders. Impairments in coagulation and fibrinolysis may not contribute to the increased vascular risk associated with excessive erythrocytosis.

ABSTRACT

Increased coagulation and reduced fibrinolysis are central factors underlying thrombotic risk and events. High altitude-induced excessive erythrocytosis (EE) is prevalent in Andean highlanders, contributing to increased cardiovascular risk. Disruption in the coagulation-fibrinolytic axis resulting in uncontrolled fibrin deposition might underlie the increased thrombotic risk associated with high-altitude EE. The experimental aim of this study was to determine whether EE is associated with a prothrombotic blood coagulation and fibrinolytic profile in Andean highlanders. Plasma coagulation factors (von Willebrand factor and factors VII, VIII and X), fibrinolytic factors [tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1)] and D-dimer levels were determined in 26 male residents of Cerro de Pasco, Peru (4340 m a.s.l.): 12 without EE (age, 40 ± 13 years; haemoglobin, 17.4 ± 1.9 g/dl) and 14 with EE (age, 43 ± 15 years; haemoglobin, 24.4 ± 1.6 g/dl). There were no significant differences in von Willebrand factor (40.5 ± 24.8 vs. 45.5 ± 22.4%), factor VII (77.0 ± 14.5 vs. 72.5 ± 8.9%), factor VIII (55.6 ± 19.8 vs. 60.7 ± 26.8%) and factor X (73.9 ± 8.3 vs. 67.3 ± 10.9%) between the Andean highlanders without or with EE. The t-PA antigen (8.5 ± 3.6 vs. 9.6 ± 5.4 ng/ml), t-PA activity (5.5 ± 2.4 vs. 5.8 ± 1.6 IU/ml), PAI antigen (45.0 ± 33.8 vs. 40.5 ± 15.8 ng/ml), PAI-1 activity (0.24 ± 0.09 vs. 0.25 ± 0.11 IU/ml) and the molar concentration ratio of active t-PA to active PAI-1 (1:0.051 ± 0.034 vs. 1:0.046 ± 0.021 mmol/l) were also similar between the groups, as were D-dimer levels (235.0 ± 126.4 vs. 268.4 ± 173.7 ng/ml). Collectively, the results of the present study indicate that EE is not associated with a hypercoagulable, hypofibrinolytic state in Andean highlanders.

Global REACH 2018: dysfunctional extracellular microvesicles in Andean highlander males with excessive erythrocytosis

High altitude-related excessive erythrocytosis (EE) is associated with increased cardiovascular risk. The experimental aim of this study was to determine the effects of microvesicles isolated from Andean highlanders with EE on endothelial cell inflammation, oxidative stress, apoptosis, and nitric oxide (NO) production. Twenty-six male residents of Cerro de Pasco, Peru (4,340 m), were studied: 12 highlanders without EE (age: 40 ± 4 yr; BMI: 26.4 ± 1.7; Hb: 17.4 ± 0.5 g/dL, Spo₂: 86.9 ± 1.0%) and 14 highlanders with EE (43 ± 4 yr; 26.2 ± 0.9; 24.4 ± 0.4 g/dL; 79.7 ± 1.6%). Microvesicles were isolated, enumerated, and collected from plasma by flow cytometry. Human umbilical vein endothelial cells were cultured and treated with microvesicles from highlanders without and with EE. Microvesicles from highlanders with EE induced significantly higher release of interleukin (IL)-6 (89.8 ± 2.7 vs. 77.1 ± 1.9 pg/mL) and IL-8 (62.0 ± 2.7 vs. 53.3 ± 2.2 pg/mL) compared with microvesicles from healthy highlanders. Although intracellular expression of total NF-κB p65 (65.3 ± 6.0 vs. 74.9 ± 7.8.9 AU) was not significantly affected in cells treated with microvesicles from highlanders without versus with EE, microvesicles from highlanders with EE resulted in an ∼25% higher (P < 0.05) expression of p-NF-κB p65 (173.6 ± 14.3 vs. 132.8 ± 12.2 AU). Cell reactive oxygen species production was significantly higher (76.4.7 ± 5.4 vs. 56.7 ± 1.7% of control) and endothelial nitric oxide synthase (p-eNOS) activation (231.3 ± 15.5 vs. 286.6 ± 23.0 AU) and NO production (8.3 ± 0.6 vs. 10.7 ± 0.7 μM/L) were significantly lower in cells treated with microvesicles from highlanders with versus without EE. Cell apoptotic susceptibility was not significantly affected by EE-related microvesicles. Circulating microvesicles from Andean highlanders with EE increased endothelial cell inflammation and oxidative stress and reduced NO production.NEW & NOTEWORTHY In this study, we determined the effects of microvesicles isolated from Andean highlanders with excessive erythrocytosis (EE) on endothelial cell inflammation, oxidative stress, apoptosis, and NO production. Microvesicles from highlanders with EE induced a dysfunctional response from endothelial cells characterized by increased cytokine release and expression of active nuclear factor-κB and reduced nitric oxide production. Andean highlanders with EE exhibit dysfunctional circulating extracellular microvesicles that induce a proinflammatory, proatherogenic endothelial phenotype.

Abstract MP26: Endothelial-derived Microvesicles From Andean Highlanders With Excessive Erythrocytosis Induce A Deleterious Cardiomyocyte Phenotype

Background: Excessive erythrocytosis (EE), defined as Hb ≥21 g/dL in men and ≥19 g/dL in women, is a pathologic consequence of residing at high altitude (>2500 m) and is common in Andean highlanders. EE is associated with increased cardiovascular risk and cardiac dysfunction. Specifically, EE has been linked to congestive heart failure as well as right ventricular hypertrophy in high altitude dwellers. The mechanisms responsible for diminished cardiac function in adults with EE remain unclear. Endothelial microvesicles (EMVs) play an important role in mediating interaction between the vascular endothelium and cardiac function. The experimental aim of this study was to determine the effects of EMVs isolated from adults with EE on markers of cardiomyocyte fibrosis, hypertrophy and autophagy as well as endothelial nitric oxide synthase (eNOS).

Methods: Twenty-four male residents of Cerro de Pasco, Peru (4,340 m) were studied: 12 highlanders without EE (Healthy; age: 40±4 yr; BMI: 26.4±1.7; Hb: 17.4±0.5 g/dL) and 12 highlanders with EE (EE: 45±5 yr; 26.7±1.0; 24.4±0.4 g/dL). All subjects were non-obese, normotensive, normolipidemic and non-diabetic. EMVs (CD31+/CD42b-) were identified, enumerated, and isolated from plasma by flow cytometry. Human induced pluripotent stem cell cardiomyocytes were cultured and treated with EMVs from either healthy or EE men.

Results: EMVs from EE men induced significantly greater expression of specific markers of fibrosis: TGF-β (91.1±4.0 vs 52.7±3.8 AU) and alpha-1 type I collagen (85.6±5.6 vs 59.7±4.8 AU) and hypertrophy: troponin T (41.4±2.0 vs 16.9±1.4 AU) and α-actinin (95.3±6.7 vs 62.4±5.0 AU) than EMVs from healthy men. Cell autophagy was not significantly affected by EE EMVs. Intercellular expression of phosphorylated eNOS at the primary activation site, Ser1177 (13.3±1.1 vs 18.9±1.2 AU), and inhibitory site, Thr495 (56.7±3.4 vs 40.8±2.7 AU), were ~35% lower and ~30% higher (both P<0.05), respectively, in cells treated with EMVs from EE compared with healthy men.

Conclusions: These data indicate that EMVs from Andean highlanders with EE negatively affect cardiomyocyte function and, therefore, may contribute to the increased risk of heart failure and cardiac dysfunction associated with EE.

Endothelin-1-induced endothelial microvesicles impair endothelial cell function

The aim of this study was to determine the effects of endothelin-1 (ET-1)-generated endothelial microvesicles (EMVs) on endothelial cell inflammation, apoptosis, and endothelial nitric oxide synthase (eNOS). Human umbilical vein endothelial cells (HUVECs) were treated with ET-1 for 24 h. EMVs released into the supernatant from cells treated with ET-1 or vehicle were isolated and quantified. EMV release was higher (P < 0.05) in cells treated with ET-1 compared with control (95 ± 15 vs. 54 ± 5 EMV/µL). Fresh HUVECs were then treated with either ET-1, ET-1-induced EMVs, or control EMVs for 24 h. ET-1-generated EMVs induced significantly higher release of IL-6 (181.0 ± 16.0 vs. 132.1 ± 8.1 pg/mL) and IL-8 (303.4 ± 37.4 vs. 211.8 ± 10.0 pg/mL), as well as greater total NF-κB p65 (76.0 ± 7.6 vs. 57.1 ± 2.1 AU) and active NF-κB p65 (Ser-536) (11.6 ± 0.9 vs. 6.8 ± 1.0 AU) expression than control EMVs. There were no significant differences in expression of caspase-9 (230.1 ± 24.3 vs. 243.6 ± 22.3 AU), caspase-3 (271.9 ± 22.7 vs. 265.1 ± 30.5 AU), and active caspase-3 (4.4 ± 0.4 vs. 4.3 ± 0.1 AU) in cells treated with ET-1-EMVs versus control EMVs. Total eNOS (108.4 ± 11.4 vs. 158.8 ± 1.6 AU) and activated eNOS (4.7 ± 0.5 vs. 9.6 ± 1.4 AU) were significantly lower in endothelial cells treated with ET-1-generated EMVs compared with control EMVs. The effects of ET-1-generated EMVs on cellular markers and mediators of endothelial inflammation, as well as eNOS function, was comparable to the effects of ET-1. In summary, ET-1 induces an EMV phenotype that adversely affects endothelial cell function. ET-1-generated EMVs may contribute to the atherogenic effect of ET-1.NEW & NOTEWORTHY Endothelin-1 (ET-1) is a potent vasoconstrictor peptide released by the endothelium that contributes to the regulation of vascular tone. Overexpression of ET-1 has been implicated in the etiology of atherosclerotic vascular disease. Endothelial cell-derived microvesicles (EMVs) play a pivotal role in vascular health and disease. Their functional phenotype is largely dictated by the stimulus for release. EMVs released in response to various pathological conditions have been shown to elicit deleterious vascular effects. In the present study, we determined, in vitro, the effect of ET-1 on EMV release from endothelial cells and the effects of ET-1-generated EMVs on endothelial cell inflammation, apoptosis, and endothelial nitric oxide synthase (eNOS). ET-1 induced a marked increase in EMV release. ET-1-generated EMVs significantly increased endothelial cell inflammation and reduced eNOS protein expression and activation. Moreover, the endothelial effects of ET-1-derived EMVs were similar to the direct effects of ET-1. ET-1-generated EMVs may contribute to the proatherogenic profile of ET-1.

Ascorbic acid inhibits vascular remodeling induced by mental stress in overweight/obese men

BACKGROUND

Mental stress (MS) is related to endothelial dysfunction in overweight/obese men. It is believed that the pro-oxidant profile, associated with an imbalance in the vascular remodeling process, may contribute to deleterious effects of MS on endothelial function. However, it is unknown whether administration of ascorbic acid (AA), a potent antioxidant, can prevent oxidative and remodeling dysfunction during MS in these subjects.

METHODS

Fourteen overweight/obese grade I men (27 ± 7 years; 29.7 ± 2.6 kg·m^-2) underwent the Stroop Color Word Test for 5 min to induce MS after AA (3 g) or placebo (PL, 0.9% NaCl) intravenous infusions. Venous blood samples were collected at baseline and the last minute of MS to measure nitrite concentration (chemiluminescence), protein carbonylation, thiobarbituric acid reactive substances (TBARS) and catalase activity (colorimetric assays), superoxide dismutase (SOD; immunoenzymatic assay), activities of active/inactive (pro) forms of metalloproteinases-9 and -2 (MMP; zymography) and its respective tissue inhibitors concentration (TIMP-1 and TIMP-2; immunoenzymatic assays).

RESULTS

At baseline, MMP-9 activity (p < 0.01), the MMP-9/proMMP-9 ratio (p = 0.02) and TIMP-1 concentration (p = 0.05) were reduced, whereas proMPP-9 activity was increased (p = 0.02) after AA compared to PL infusion. After PL infusion, MS increased protein carbonylation (p < 0.01), catalase (p < 0.01), and the MMP-9/proMMP-9 ratio (p = 0.04) when compared to baseline. AA infusion reduced protein carbonylation (p = 0.02), MMP-9 activity (p < 0.01), and MMP-9/pro-MMP-9 ratio (p < 0.01), while SOD (p = 0.04 vs baseline), proMPP-9 (p < 0.01 vs PL), MMP-2 (p < 0.01 vs PL) and TIMP-2 (p = 0.02 vs baseline) remained elevated during MS.

CONCLUSIONS

AA appears to minimize the oxidative imbalance and vascular remodeling induced by MS.

Differential vasomotor responses to isocapnic hyperoxia: cerebral versus peripheral circulation

Isocapnic hyperoxia (IH) evokes cerebral and peripheral hypoperfusion via both disturbance of redox homeostasis and reduction in nitric oxide (NO) bioavailability. However, it is not clear whether the magnitude of the vasomotor responses depends on the vessel network exposed to IH. To test the hypothesis that the magnitude of IH-induced reduction in peripheral blood flow (BF) may differ from the hypoperfusion response observed in the cerebral vascular network under oxygen-enriched conditions, nine healthy men (25 ± 3 yr, mean ± SD) underwent 10 min of IH during either saline or vitamin C (3 g) infusion, separately. Femoral artery (FA), internal carotid artery (ICA), and vertebral artery (VA) BF (Doppler ultrasound), as well as arterial oxidant (8-isoprostane), antioxidant [ascorbic acid (AA)], and NO bioavailability (nitrite) markers were simultaneously measured. IH increased 8-isoprostane levels and reduced nitrite levels; these responses were followed by a reduction in both FA BF and ICA BF, whereas VA BF did not change. Absolute and relative reductions in FA BF were greater than IH-induced changes in ICA and VA perfusion. Vitamin C infusion increased arterial AA levels and abolished the IH-induced increase in 8-isoprostane levels and reduction in nitrite levels. Whereas ICA and VA BF did not change during the vitamin C-IH trial, FA perfusion increased and reached similar levels to those observed during normoxia with saline infusion. Therefore, the magnitude of IH-induced reduction in femoral blood flow is greater than that observed in the vessel network of the brain, which might involve the determinant contribution that NO has in the regulation of peripheral vascular perfusion.

Human brain blood flow and metabolism during isocapnic hyperoxia: the role of reactive oxygen species

KEY POINTS

It is unknown whether excessive reactive oxygen species (ROS) production drives the isocapnic hyperoxia (IH)-induced decline in human cerebral blood flow (CBF) via reduced nitric oxide (NO) bioavailability and leads to disruption of the blood-brain barrier (BBB) or neural-parenchymal damage. Cerebral metabolic rate for oxygen (CMR O 2 ) and transcerebral exchanges of NO end-products, oxidants, antioxidants and neural-parenchymal damage markers were simultaneously quantified under IH with intravenous saline and ascorbic acid infusion. CBF and CMR O 2 were reduced during IH, responses that were followed by increased oxidative stress and reduced NO bioavailability when saline was infused. No indication of neural-parenchymal damage or disruption of the BBB was observed during IH. Antioxidant defences were increased during ascorbic acid infusion, while CBF, CMR O 2 , oxidant and NO bioavailability markers remained unchanged. ROS play a role in the regulation of CBF and metabolism during IH without evidence of BBB disruption or neural-parenchymal damage.

ABSTRACT

To test the hypothesis that isocapnic hyperoxia (IH) affects cerebral blood flow (CBF) and metabolism through exaggerated reactive oxygen species (ROS) production, reduced nitric oxide (NO) bioavailability, disturbances in the blood-brain barrier (BBB) and neural-parenchymal homeostasis, 10 men (24 ± 1 years) were exposed to a 10 min IH trial (100% O₂ ) while receiving intravenous saline and ascorbic acid (AA, 3 g) infusion. Internal carotid artery blood flow (ICABF), vertebral artery blood flow (VABF) and total CBF (tCBF, Doppler ultrasound) were determined. Arterial and right internal jugular venous blood was sampled to quantify the cerebral metabolic rate of oxygen (CMR O 2 ), transcerebral exchanges (TCE) of NO end-products (plasma nitrite), antioxidants (AA and AA plus dehydroascorbic acid (AA+DA)) and oxidant biomarkers (thiobarbituric acid-reactive substances (TBARS) and 8-isoprostane), and an index of BBB disruption and neuronal-parenchymal damage (neuron-specific enolase; NSE). IH reduced ICABF, tCBF and CMR O 2 , while VABF remained unchanged. Arterial 8-isoprostane and nitrite TCE increased, indicating that CBF decline was related to ROS production and reduced NO bioavailability. AA, AA+DA and NSE TCE did not change during IH. AA infusion did not change the resting haemodynamic and metabolic parameters but raised antioxidant defences, as indicated by increased AA/AA+DA concentrations. Negative AA+DA TCE, unchanged nitrite, reductions in arterial and venous 8-isoprostane, and TBARS TCE indicated that AA infusion effectively inhibited ROS production and preserved NO bioavailability. Similarly, AA infusion prevented IH-induced decline in regional and total CBF and re-established CMR O 2 . These findings indicate that ROS play a role in CBF regulation and metabolism during IH without evidence of BBB disruption or neural-parenchymal damage.

Intrathecal fentanyl abolishes the exaggerated blood pressure response to cycling in hypertensive men

KEY POINTS

The increase in blood pressure observed during physical activities is exaggerated in patients with hypertension, exposing them to a higher cardiovascular risk. Neural signals from the skeletal muscles appear to be overactive, resulting in this abnormal response in hypertensive patients. In the present study, we tested whether the attenuation of these neural signals in hypertensive patients could normalize their abnormal increase in blood pressure during physical activity. Attenuation of the neural signals from the leg muscles with intrathecal fentanyl injection reduced the blood pressure of hypertensive men during cycling exercise to a level comparable to that of normotensive men. Skeletal muscle afferent overactivity causes the abnormal cardiovascular response to exercise and was reverted in this experimental model, appearing as potential target for treatment. Hypertensive patients present an exaggerated increase in blood pressure and an elevated cardiovascular risk during exercise. Although controversial, human studies suggest that group III and IV skeletal muscle afferents might contribute to this abnormal response. In the present study, we investigated whether attenuation of the group III and IV muscle afferent signal of hypertensive men eliminates the exaggerated increase in blood pressure occurring during exercise. Eight hypertensive men performed two sessions of 5 min of cycling exercise at 40 W. Between sessions, the subjects were provided with a lumbar intrathecal injection of fentanyl, a μ-opioid receptor agonist, aiming to attenuate the central projection of opioid-sensitive group III and IV muscle afferent nerves. The cardiovascular response to exercise of these subjects was compared with that of six normotensive men. During cycling, the hypertensive group demonstrated an exaggerated increase in blood pressure compared to the normotensive group (mean ± SEM: +17 ± 3 vs. +8 ± 1 mmHg, respectively; P < 0.05), whereas the increase in heart rate, stroke volume, cardiac output and vascular conductance was similar (P > 0.05). Fentanyl inhibited the blood pressure response to exercise in the hypertensive group (+11 ± 2 mmHg) to a level comparable to that of the normotensive group (P > 0.05). Moreover, fentanyl increased the responses of vascular conductance and stroke volume to exercise (P < 0.05), whereas the heart rate response was attenuated (P < 0.05) and the cardiac output response was maintained (P > 0.05). The results of the present study show that attenuation of the exercise pressor reflex normalizes the blood pressure response to cycling exercise in hypertensive individuals.

eNOS gene haplotype is indirectly associated with the recovery of cardiovascular autonomic modulation from exercise

Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene decrease expression and activation of eNOS in vitro, which is associated with lower post-exercise increase in vasodilator reactivity in vivo. However, it is unknown whether such polymorphisms are associated with other eNOS-related phenotypes during recovery from exercise. Therefore, we investigated the impact of an eNOS haplotype containing polymorphic alleles at loci -786 and 894 on the recovery of cardiovascular autonomic function from exercise. Sedentary, non-obese, healthy subjects were enrolled [n = 107, age 32 ± 1 years (mean ± SEM)]. Resting autonomic modulation (heart rate variability, systolic blood pressure variability, and spontaneous baroreflex sensitivity) and vascular reactivity (forearm hyperemic response post-ischemia) were assessed at baseline, 10, 60, and 120 min after a maximal cardiopulmonary exercise test. Besides, autonomic function was assessed by heart rate recovery (HRR) immediately after peak exercise. Haplotype analysis showed that vagal modulation (i.e., HF n.u.) was significantly higher, combined sympathetic and vagal modulation (i.e., LF/HF) was significantly lower and total blood pressure variability was significantly lower post-exercise in a haplotype containing polymorphic alleles (H2) compared to a haplotype with wild type alleles (H1). HRR was similar between groups. Corroborating previous evidence, H2 had significantly lower post-exercise increase in vasodilator reactivity than H1. In conclusion, a haplotype containing polymorphic alleles at loci -786 and 894 had enhanced recovery of autonomic modulation from exercise, along with unchanged HRR, and attenuated vasodilator reactivity. Then, these results suggest an autonomic compensatory response of a direct deleterious effect of eNOS polymorphisms on the vascular function.

Trisomy 10 in acute myeloid leukemia: report of a new case

We report a case of acute myeloid leukemia (AML) with trisomy 10 as the sole abnormality. We have observed this case among 202 de novo and untreated AML examined cytogenetically in our laboratory during the last 10 years. The patient was an adult man diagnosed with AML-M2. An interesting morphologic finding was the presence in light microscopy and ultrastructural studies of prominent giant "Chediak-Higashi-like" granules in some of the leukemic cells. Cell marker studies showed positivity for CD7 and CD33, as seen in the six previously reported cases. The prognosis has been moderate-good, with a survival of 33 months. Trisomy 10 in AML appears to be a rare recurring numeric chromosomal abnormality and probably linked to a myeloblast subset with a CD33+ and CD7+ phenotype.