bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogen peroxide‐induced oxidative damage and apoptosis in endothelial cells: protection by luteolin
Authors: Hsu Pei‐Tzu , Huang Chih‐yang , Ou Hsiu‐Chung
Published: June 2021

Oxidative stress has recently been implicated in the pathogenesis of atherosclerotic cardiovascular diseases. Dietary supplement of antioxidants has been reported to have beneficial effects on prevention of atherogenic diseases. However, the underlying mechanisms are still largely unknown. Luteolin, a naturally occurring polyphenol flavonoid, has demonstrated some beneficial modulation toward the endothelium. This study aims to investigate the effects of luteolin on hydrogen peroxide (H2O2)‐induced apoptosis, a key event in the pathogenesis of atherosclerosis, in endothelial cells. Our results showed that pretreatment of human umbilical vein endothelial cells (HUVECs) with luteolin before exposure to H2O2 markedly reduced not only H2O2‐induced cell death but also lactate dehydrogenase (LDH) leakage. H2O2‐induced apoptosis is characterized by a calcium‐dependent mitochondrial pathway, involving increased intracellular calcium, disturbed the balance of Bcl‐2 family proteins, destabilized mitochondria membrane potential, increased the amount of cytochrome c release to cytosol and consequent caspase‐3 activation. These detrimental effects were ameliorated dose‐dependently by luteolin. These results suggested that luteolin inhibits oxidative stress‐induced apoptosis in endothelial cells through the blockage of the calcium‐dependent mitochondrial pathway.
Flow‐Mediated Vasodilation and Endothelin‐1
Authors: Wray D. Walter , Nishiyama Steven K , Zhao Jia , Richardson Russell S
Published: June 2021

Endothelin‐1 (ET‐1), a potent vasoconstrictor produced by vascular endothelial cells, has been implicated in the pathophysiology of numerous cardiovascular diseases, yet the direct impact of ET‐1 on vascular function remains unclear. Therefore, in seven young (23 ± 1 yrs) healthy subjects, we investigated the effect of an intra‐arterial infusion of ET‐1 on reactive hyperemia (RH) and flow‐mediated dilation (FMD) in the popliteal artery. ET‐1 infusion significantly attenuated basal leg blood flow (Control: 62 ± 4, ET‐1: 47 ± 9 ml/min), and RH (total (area under curve (AUC)) and peak) (AUC: Control: 162 ± 15 ml, ET‐1: 104 ± 16 ml; Peak: Control: 572 ± 51 ml/min, ET‐1: 412 ± 32 ml/min) (P < 0.05). FMD was significantly attenuated as a result of the ET‐1 infusion (Control: 2.4 ± 0.3 %, ET‐1: 0.5 ± 0.5 %; FMD/shear rate: Control: 10.5 × 10−4 ± 2.0 ×10−4 ET‐1: 0.9 × 10−4 ± 2.8 × 10−4 % Δ/s‐1•s; P < 0.05). These findings demonstrate that elevated levels of ET‐1 have a significant impact on FMD, suggesting studies that employ FMD as a marker of endothelial function and nitric oxide bioavailability should exercise caution, as ET‐1 can also tip the balance between vasodilation and vasoconstriction.
Hypertonic saline attenuates cutaneous vasodilation in response to local heating
Authors: DuPont Jennifer J , Farquhar William B , Edwards David G
Published: June 2021

Salt may have a direct effect on vascular function by reducing nitric oxide (NO) production.

PURPOSE

The purpose of this study was to examine the effects of hypertonic saline on NO‐mediated cutaneous vasodilation in response to local heating.

METHODS

Nine healthy subjects (23 ± 2 years) were studied. We measured cutaneous red blood cell flux via laser Doppler in conjunction with intradermal microdialysis of 1) Ringer's solution (R), 2) 0.9% normal saline (NS), 3) 3% hypertonic saline (HS), and 4) 10 mM NG‐nitro‐L‐arginine methyl ester (L‐NAME) during local heating to 42°C. Microdialysis of 28 mM sodium nitroprusside (SNP) at 43°C was used for assessment of maximum cutaneous vascular conductance (CVCmax) and data was expressed as a percentage of CVCmax (%CVCmax).

RESULTS

Baseline %CVCmax did not differ between the four microdialysis sites (HS: 9 ± 4, R: 11 ± 6, NS: 7 ± 4, L‐NAME: 7 ± 2%; p = 0.9). Hypertonic saline significantly attenuated the plateau %CVCmax compared to Ringer's and 0.9% normal saline (HS: 74 ± 12, R: 89 ± 4, NS: 89 ± 5%; p< 0.01) and L‐NAME reduced the plateau %CVCmax compared to other three sites (47 ± 7%, p< 0.01).

CONCLUSION

Hypertonic saline attenuates the cutaneous vasodilation response to local heating suggesting a direct effect of salt on microvascular function. This effect may be mediated through a decreased production and/or availability of NO.

Supported by Grant DK080469.
25‐Hydroxyvitamin D deficiency is associated with vascular endothelial dysfunction in middle‐aged and older adults
Authors: Jablonski Kristen L , Pierce Gary L , Walker Ashley E , Chonchol Michel , Seals Douglas R
Published: June 2021

Aging is associated with impaired endothelium‐dependent dilation (EDD) and increased 25‐hydroxyvitamin D (25(OH)D) deficiency. 25(OH)D deficiency is predictive of incident cardiovascular events and mortality. We hypothesized that healthy middle‐aged and older adults (MA/O) who were 25(OH)D insufficient (20–29 ng/mL) or deficient (<20 ng/mL) would demonstrate greater impairment in EDD compared with their 25(OH)D sufficient (>30 ng/mL) peers. Groups did not differ in cardiovascular risk factors or physical activity/fitness. EDD, measured using brachial artery flow‐mediated dilation (FMD), was 25% and 42% lower in insufficient (63±1 yr, n=24, mean±S.E.) and deficient (64±1 yr, n=14) vs. sufficient (60±2 yr, n=8) subjects (3.0±0.3 vs. 3.9±0.3 vs. 5.2±0.5 %, p<0.01), whereas endothelium‐independent dilation (brachial dilation to sublingual nitroglycerine) did not differ among groups (p=0.30). In the overall sample, 25(OH)D was positively related to FMD (r= 0.50; p<0.01) and inversely related to vascular endothelial cell nitrotryosine, a marker of oxidative damage (n=24; r=−0.63; p<0.01). These results indicate that lower circulating 25(OH)D may contribute to oxidative stress‐associated impairment of EDD among healthy MA/O, and suggest vitamin D supplementation may improve EDD in this group.

NIH AG013038, AG022241, AG006537, AG0015897, AG03114, AG033994, RR00051
VPAC2 And/Or PAC1 Receptors Interact with NOS during Heat Stress in Humans
Authors: Zhao Joan L , Kellogg Dean L , Wu Yubo , Johnson John M
Published: June 2021

VPAC2 and/or PAC1 receptors are implicated in cutaneous active vasodilation(AVD) during heat stress(HS). Nitric oxide(NO) from NOS also plays important roles in HS in humans. We hypothesized that NO and VPAC2/PAC1 interact in AVD during HS. We examined this interaction by testing the effects of specific blockade of these receptors with and without NOS inhibition during HS. The VPAC2/PAC1 antagonist, Pituitary Adenylate Cyclase Activating Peptide 6‐38(PACAP6‐38) and the NOS inhibitor, L‐NAME(LNM) were used. PACAP6‐38, LNM, a combination(MIX) of PACAP6‐38 and LNM, or Ringer's solution alone were perfused at 4 separate intradermal microdialysis sites. Skin blood flow(SkBF) was monitored by aser‐Doppler flowmetry and body temperature controlled with water‐perfused suits. The protocol began with a 10 minute baseline period without antagonist perfusion. This was followed by 45 minutes of PACAP6‐38, L‐NM or Mix perfusion at respective site in normothermia(Norm). Norm was followed by a 3‐minute period of whole body cooling (CS). Whole body heating was then performed to effect HS and activate AVD. After HS, 58mM sodium nitroprusside was perfused at all MD sites to effect maximal vasodilation for data normalization. No differences were found between Ringer's and PACAP6‐38, L‐NAME, or MIX sites during Norm(p>0.05 among sites) or CS(p>0.05 among sites). All three treated sites attenuated AVD in HS when compared to Ringer's sites(p<0.05). Greater attenuation occurred at LNM and MIX sites than in PACAP6‐38 sites(p<0.05); however, AVD attenuation was not different between LNM and MIX treated sites(P>0.05, LNM vs MIX). We conclude that VPAC2/PAC1 receptors interact with NO during AVD. (supported by NIH Grant HL065599)
Food insecurity is prevalent in rural communities of El Salvador, Guatemala, Honduras and Nicaragua
Authors: Bermudez Odilia I. , de Fulladolsa Patricia Palma , Deman Hedi , Melgar‐Quinones Hugo
Published: June 2021

Introduction

Although food insecurity affects groups in Central America, little is known about the magnitud and severity of this situation.

Objectives

To assess psychometric properties of the 15‐item Food Security (FS) Scale for Latin American (ELCSA) and estimate FS in rural households (HH) of El Salvador (Sal), Guatemala (Gua), Honduras (Hon) and Nicaragua (Nic)

Methods

We assesed reliability and tested a Rasch model of the ELCSA and evaluated levels of FS in 502 families (Sal=180, Gua=120, Hon=64; Nic=138).

Results

Cronbach's alpha was 0.90 with inter item correlation of 0 0.37, range=0.09–0.74. From Rasch analysis, we found that the less severe item was question1 about worrying for not having enough food (Measure = −4.6). and the most severe (6.5) was the item on children not eating in a day. Excluding question1, the INFIT values ranged from 0.8 to 1.2. Very low FS was highly prevalent in the studied HH: Nic=50%, Hon=31%, Gua=18% and Sal=14%.

Conclusions

The ELCSA was valid and reliable for measuring FS in Central America. The levels of very low FS were highly prevalent, therefore additional efforts are needed to protect those vulnerable population groups.
Chronic Losartan Prevents Hypertension in Female Dahl Salt Sensitive Rats
Authors: Esqueda Ma. Eugenia Davila , Franklin Cindy , Fortepiani Lourdes , Hinojosa‐Laborde Carmen
Published: June 2021

Dahl salt‐sensitive female rats (DSSF) represent a model of postmenopausal hypertension because they develop hypertension (HT) as they age from 4 to 15 months (m) which is exacerbated with estrogen loss. Mean arterial pressure (MAP) increases significantly from 122±3 mm Hg at age 4 m to166±7 mm Hg at age 15 m, with less than 50% survival rate. Acute blockade of the renin angiotensin system (RAS) reduces MAP to normotensive levels in DSSF indicating that postmenopausal HT is associated with activation of the RAS. We hypothesize that chronic blockade of the RAS will prevent the development of HT in DSSF as they age from 4 to 15 m and increase their life span. At age 2 m, DSSF were given the angiotensin receptor blocker, losartan, in the drinking water (30mg/kg/day), and continued until the rats were 15 m old. MAP was monitored from 4 m to 15 m of age with radiotelemetry. MAP (mean ± SEM) in losartan treated DSSF was 106±3, 105±3, 109±3, 102±5, 104±5, and 112±4 mm Hg at age 4, 6, 8, 10, 12 and 15 m, respectively. MAP in losartan treated DSSF was not different between ages, and was significantly (p<0.05) lower compared to non‐treated DSSF previously studied. All losartan treated DSSF survived to 15 months of age. This study revealed that chronic blockade of the RAS prevents HT and extends lifespan in DSSF, and provides evidence that therapies which interfere with the RAS would be highly effective in the treatment of postmenopausal HT.
Early life stress reduces renal function in male rats
Authors: Loria Analia Silvina , Lee Jessica , Martin Brian , Pollock David , Pollock Jennifer
Published: June 2021

The first aim of this study was to investigate whether exposure to early life stress, maternal separation (MS), renders sex‐specific effects on basal creatinine clearance (Ccreat) and proteinuria (UprotV). Previously, we reported that male rats exposed to MS display enhanced sensitivity to chronic ang II infusion compared to normally‐reared control (C) male rats. Thus, the second aim was to determine whether female MS rats also display enhanced sensitivity to a chronic infusion of ang II. MS was performed in male and female WKY rats 3 hrs/day from day 2 to 14 of life. Plasma and 24 hr urine samples were collected at baseline (12 wks old). Ccreat was reduced in male MS (n=5) compared to C (n=7) rats (1.32±0.10 vs. 0.99±0.09 ml/min, respectively, p<0.05). Similar Ccreat was observed in female MS and C rats (n=6). UprotV was significantly higher in males than females (p<0.05), however it was similar between MS and C rats. Female MS and C rats were implanted with ang II osmotic mini‐pumps (65 ng/min, sc) and blood pressure (MAP) monitored by telemetry for 2 wks. MAP was similar in female MS and C rats at baseline. Female MS rats displayed greater sensitivity to ang II‐induced hypertension (153±5 vs. 137±5 mmHg, respectively, n=3–4, p<0.05). These studies suggest that early life stress reduces GFR in male but not female rats, while enhanced blood pressure sensitivity to ang II is evident in both sexes.
Bioavailability of nitric oxide is impaired in hypertensive male IUGR offspring.
Authors: Hennington Bettye Sue , Jones E. Jenae , Taylor Lateia , Trocquet Danielle M. , Ojeda Norma B. , Royals Thomas B. , Alexander Barbara T.
Published: June 2021

Our laboratory utilizes a rat model of placental insufficiency that results in intrauterine growth restriction (IUGR) and hypertension in male IUGR. The purpose of this study was to determine whether impaired nitric oxide (NO) bioavailability contributes to male IUGR hypertension. L‐NAME (nitro‐L‐arginine methyl ester, 10mg/kg/Day) was given in the drinking water for 40 days. Mean arterial pressure (MAP), measured in conscious chronically catheterized rats, was significantly increased in untreated IUGR relative to untreated control (133±3 vs. 122±4 mmHg, P<0.05; IUGR vs. control, respectively). The increase in MAP in response to chronic L‐NAME was greater in control (Ä66 mmHg, 188±12 mmHg, P<0.05 vs. untreated control) as compared to the increase in MAP observed in IUGR (Ä43 mmHg 176±14 mmHg, P<0.05 vs. untreated IUGR). Therefore, these data indicate that control rats were more responsive to NO synthase (NOS) inhibition than IUGR, and that bioavailability of NO may be limited in male IUGR rats. Protein expression of the renal NOS isoforms were significantly reduced upon comparison of male IUGR to male control (eNOS: IUGR indicated 78% of Control; iNOS: IUGR 76% of Control; phosphorylated nNOS IUGR 81% of Control). Thus, these data suggest that a decrease in renal NOS isoform expression may contribute to the reduction in NO bioavailability observed in male IUGR offspring.
Two‐Week Intermittent Hypoxia (IH) Conditioning Improves Cerebral Tissue Oxygenation during Hypercapnia
Authors: Zhang Peizhen , Downey Fred , Shi Xiangrong
Published: June 2021

We examined the effect of IH (10% O2) conditioning on cerebral perfusion and oxygenation of 8 healthy volunteers (25.0±1.1 yr). The study was approved by IRB at UNTHSC. IH started with 5 bouts of 5‐min exposure alternating with 4‐min inhalation of room air and progressively increased to 10 bouts of 6‐min exposure on Day 7 through Day 14. Middle cerebral arterial blood flow velocity (VMCA) and regional cerebral O2 saturation (ScO2) were continuously measured during rebreathing (~6 min) induced increases in PETCO2. Continuous cerebral vascular conductance (CVC, the ratio of VMCA to mean arterial pressure) and ScO2 were averaged every 30 sec and the rate of % changes (Ä) during hypercapnia was compared. The rebreathing progressively raised PETCO2 from 41.4±1.1 to 56.6±1.5 mmHg pre and from 40.2±0.9 to 54.6±1.6 mmHg post, which were not statistically different pre and post IH conditioning. In response to unit hypercapnia, the rate of increases in group CVC was greater (P < 0.01) pre (2.87±0.16 %/mmHg) than post (2.12±0.12 %/mmHg); whereas the rate of increases in group ScO2 was smaller (P < 0.01) pre (1.08±0.04 %/mmHg) than post (1.22±0.04 %/mmHg). The slope of ÄScO2/ÄCVC was augmented (P < 0.01) following IH conditioning, i.e., pre vs post: 0.37±0.02 vs 0.56±0.03. Two‐week IH conditioning enhanced cerebral tissue oxygenation during hypercapnia even though cerebral arterial vasodilation to CO2 stimulus was diminished.
Evidence for distributed processing during hypoxic stimulation by the brainstem cardiorespiratory network
Authors: Morris Kendall , Ott Mackenzie M , Nuding Sarah C , Segers Lauren S , O'Connor Russell , Dick Thomas E , Solomon Irene C , Shannon Roger , Lindsey Bruce G
Published: June 2021

Brainstem neural networks play an important integrative role in the regulation of respiratory and cardiovascular responses to hypoxia, but their organization remains poorly understood. We addressed the hypothesis that a distributed brainstem network, including rostral medullary neurons (RMNs) in the region of the retrotrapezoid nucleus, dorsolateral pons, raphé, and ventrolateral cardiorespiratory column (VRC), integrate central and peripheral chemoreceptor inputs. Data were obtained from decerebrate adult cats. We used multi‐electrode arrays to record from up to 118 neurons simultaneously. Firing rate responses were measured during hypoxia and stimulation of central chemoreceptors. Spike trains were also analyzed with respiratory and cardiac cycle triggered histograms and cross correlation. Results include: 1. Multiple cardiorespiratory rhythms in neurons responsive to hypoxic stimulation. 2. Co‐expression of distributed eupneic network activity present together with gasp patterns during recovery from severe brain hypoxia. 3. Reciprocal effective RMN‐VRC connectivity of neurons responsive to both hypoxia and hypercapnia. The results suggest a brainstem network architecture with connectivity that shapes the respiratory motor pattern via overlapping circuits that modulate central and peripheral chemoreceptor‐mediated influences on breathing.

Supported by NS19814, NS46062
Molecular analysis of six skeletal muscles of the African cheetah, a case study
Authors: Brooks Naomi Elisabeth , Hoffman Louw , Myburgh Kathy H
Published: June 2021

The African cheetah (Acinonyx jubatus) is one of the fastest animals on earth, reaching running speeds of greater than 110 km/h and accelerating to 110 km/h in 3s. Despite these exceptional speeds, little analysis has been done on their skeletal muscles. The aim of the current study was to investigate molecular aspects of skeletal muscle from the Acinonyx jubatus. Samples were collected from six muscles of the cheetah: longissimus dorsi (LD), supraspinatus (SS), infraspinatus (IS), semimembranosus (SM), semitendinosus (ST), biceps femoris (BF). Samples were compared to slow twitch (soleus) and fast twitch (plantaris) muscle of rat and human vastus lateralis muscle. MCT1, MCT4, myostatin and GLUT4 protein levels were measured by western blot. Cheetah muscles contained lower levels of MCT1 than rat soleus. MCT1 levels were high in soleus muscle, indicative of its integral role in transporting lactate into slow twitch muscle. Levels of GLUT4 were higher in the cheetah SS, IS, ST, BF than in LD, SM, and both rat muscles which may be reflective of the different glucose uptake and exercise capacity. Lower levels of myostatin were noted in cheetah compared to rat muscle and this may contribute to the lean and highly muscular physique of the cheetah and also aid strength for elite sprinting speed. Analysis of cheetah muscle characteristics provides insight into the molecular basis of their extreme sprinting ability.
Cyclooxygenase enzyme activation in human skeletal muscle after acute resistance exercise
Authors: Del Mundo Jonathan D , Pierce Nick B , McMullan David R , Ramos Jahir E , Whitt Jamie A , Letham Tanya , Worden Kate , Carroll Chad C
Published: June 2021

The purpose of this study was to evaluate cyclooxygenase (COX)‐1 and ‐2 activation in response to an acute bout of resistance exercise (RE) in human skeletal muscle. Before, 4, and 24 hours after a bout of unilateral knee extensor RE (3 sets of 10 repetitions at 70% of maximum) muscle biopsies were taken from the vastus lateralis of seven young males (25±0.4 y). Biopsy samples were assayed for COX‐1 and COX‐2 activity (700200, Cayman Chemical). COX‐1 activity was not increased with RE (PRE: 5.0±1.0, 4 hrs: 6.5±1.1, 24 hrs: 7.7±1.9 nmol PGH2·g muscle−1·min−1) while COX‐2 activity was elevated at 24 (p<0.05) but not four hours after exercise (PRE: 4.5±1.1, 4 hrs: 5.8±1.1, 24 hrs: 8.9±1.4 nmol PGH2·g muscle−1·min−1). Prostaglandin (PG) production due to COX‐1 and COX‐2 was similar (COX‐1/COX‐2 ratio: 1.1±0.3) before RE. This ratio (0.8±0.3) decreased at 24 hours indicating a greater proportion of PG production from COX‐2. COX activity has been implicated as a necessary component of a RE‐induced increase in skeletal muscle protein synthesis. Muscle protein synthesis is elevated as early as 1–4 hours after RE. Thus our data suggest that an elevation in COX‐1 or COX‐2 activity may not be necessary for the RE‐induced increase in protein synthesis. Our findings also support the general consensus that COX‐2 is inducible and that COX‐2 enzyme activity is present in resting skeletal muscle.

Funding: MWU Start‐Up Funds, and MWU College of Health Sciences
Novel correction method for NADH interference in mitochondrial Ca2+ measurement with Fura‐2‐FF in single permeabilized ventricular myocytes of rat
Authors: Lee Jeong‐Hoon , Ha Jeong‐Mi , Kim Min‐Jeong , Leem Chae‐Hun
Published: June 2021

Fura‐2‐FF is a ratiometric fluorescent dye to measure Ca2+ quantitatively. However, there are serious obstacles for using to measure mitochondrial Ca2+ because of the interference of abundant NADH in the mitochondria and Ca2+ dependent change of NADH. These interferences limit ratiometric quantitative measurement of mitochondrial Ca2+. We used the principle that the emission intensity ratio of two different excitation lights must be constant. With this principle, we could develop a novel NADH signal correction method. When we compared mitochondria Ca2+ dynamics with Fura‐2‐FF and Rhod‐2 simultaneously, we found Rhod‐2 showed much slower kinetics than Fura‐2‐FF. We thought Rhod‐2 is not an appropriate dye to measure Ca2+. The half activation concentration of Na+ for Na+‐dependent Ca2+‐efflux was about 0.13 mM which was far different from the previous results (3.6 mM Saotome, 2005 and 4.4 mM Sedova, 2000). The maximum reachable Ca2+ concentration in the mitochondria in any cytosolic Ca2+ concentration is about 15 to 20 ¥ìM, which is far below the equilibrium concentration for electrochemical gradient. This method can be very useful when NADH interference is expected. (supported by MHWF, A084776)
The Central Effects of Angiotensin II Mediate Peripheral T lymphocyte Activation During Hypertension
Authors: Marvar Paul J , Guzik Tom J , Gordon Frank J , Harrison David G
Published: June 2021

We have found that T cells are essential in the development of angiotensin II induced hypertension. Angiotensin II (Ang II) could directly activate T cells or might exert its effects via actions in the central nervous system. To test this hypothesis we examined the effects of anteroventral third ventricle region (AV3V) ablation, which blocks the central effects of Ang II. Following 2 weeks of peripheral Ang II infusion, the blood pressure in mice that received AV3V lesions was significantly attenuated compared to the sham group (Sham:173 ± 4.6 mmHg; AV3V:137 ± 5.3 mmHg). As determined by FACS analysis, the increase in percent circulating CD4+ cells expressing the early activation marker CD69 (Sham:15.6 ± 1.1, vs. AV3V: 8.2 ± 1.4) and the total number of aortic infiltrating leukocytes (CD45+) and T cells (CD3+) were also significantly attenuated by AV3V ablation. The increase in blood pressure (Sham:163 ± 3.6 mmHg; AV3V: 166 ± 3.1 mmHg) and T cell response to another hypertensive stimulus (norepinephrine infusion) was unaffected by AV3V ablation. Administration of hydralazine attenuated the elevation in blood pressure following Ang II infusion and also prevented the increase in T cell activation and number of vascular infiltrating CD45+ and CD3+ cells. These data indicate that the central effects of Ang II and blood pressure elevation contribute to the activation of T cells and the development of vascular inflammation.
Modulation of postjunctional α‐adrenergic vasoconstriction during exercise and exogenous ATP infusions in aging humans
Authors: Kirby Brett S , Richards Jennifer C , Crecelius Anne R , Voyles Wyatt F , Dinenno Frank A
Published: June 2021

The ability to modulate α‐adrenergic vasoconstriction in contracting muscle is impaired with age. In young adults, adenosine triphosphate (ATP) has been shown to inhibit vasoconstrictor responsiveness similar to exercise. We tested the hypothesis that modulation of postjunctional α‐adrenergic vasoconstriction to exogenous ATP is impaired in aging humans. We measured forearm blood flow (FBF; Doppler ultrasound) and calculated vascular conductance (FVC) to intra‐arterial infusions of phenylephrine (α1‐agonist) and dexmedetomidine (α2‐agonist) during rhythmic handgrip exercise (15% MVC), a control non‐exercise vasodilator condition (adenosine), and ATP infusion in 7 young (22±1) and 7 older (64±3 yrs) adults. Forearm hyperemia was matched across all conditions. During adenosine, forearm vasoconstrictor responses to direct α1‐stimulation were lower in older adults (ΔFVC= −25±3 vs −41±5%); the responses to α2‐stimulation were not different (−38±5% vs −44±7%). The ability to blunt α1‐ and α2‐vasoconstriction was impaired in older adults during exercise (α1 = 31±9 vs 74±8%; α2 = 28±10 vs 60±10%). In contrast, ATP reduced the vasoconstrictor responses by ~85–90% in both age groups. We conclude that the sympatholytic effect of exogenous ATP is not reduced with age, and thus blunted ATP release during exercise may contribute to the impaired exercise sympatholysis in older adults.

Supported by HL‐087952
Overweight duration and metabolic syndrome among Filipino women
Authors: Lee Nanette R , Feranil Alan B , Adair Linda S
Published: June 2021

Excess body fat has adverse metabolic effects, but it is less clear whether the duration of being overweight (OW=BMI>=25 kg/m2)) is associated with metabolic risk factors, especially among Asians. We aimed to examine the association of OW duration with metabolic syndrome (MetS), independent of current BMI, using data from 1867 women (ages 35–68 yr) from the Cebu Longitudinal Health and Nutrition Survey in 2005. MetS was defined as having 3 of 5 components: waist circumference >=88 cm, triglyceride >=150 mg/dL, HDL‐C <50 mg/dL, blood pressure >= 130/85 mmHg, and fasting glucose >=100 mg/dL). About 48% of women had MetS, 25% were OW >10 yrs, 11% were OW 3–10 yrs, 6% were OW <3 yrs, 10% had a history of OW but not currently OW and 48% were never OW (48%). Logistic regression analyses adjusted for current BMI, age, menopausal status and other confounders showed that the odds of MetS increased with OW duration. Odds (95% CI) of MetS were highest among women with longest OW duration: 2.1 (1.3, 3.3) for OW>10 yrs, 1.6 (1.0, 2.4) for OW 3–10 yrs, and 0.7 (0.5, 1.2) for OW<3 yrs compared to never OW women. Linear regression analyses showed that increasing OW duration was associated with the total number of MetS components. With cardiovascular diseases as the main cause of mortality and morbidity in the country, results of this study underscore the need to pursue programs that prevent chronic OW. NIH 5 R01 HL085144‐03 and 1R01TW008288‐01.
Visceral and subcutaneous adipose tissues: variation in fatty acid composition and gene expression in nutritionally controlled dogs.
Authors: Le Bloc'h Jérôme , Leray Véronique , Martin Lucile , Dumon Henri , Ouguerram Khadija , Nguyen Patrick
Published: June 2021

Visceral adipose tissue (VAT) is known to be more implicated in various pathological situations than subcutaneous adipose tissue (SCAT), notably in the insulin resistance (IR) syndrome. However, the molecular bases of these observations have not been fully elucidated. The aim of this study was to examine if there are differences between these two tissues and if these differences could account, at least in part, for the higher deleterious impact of VAT. Fatty acid (FA) composition of VAT and SCAT was determined in obese IR dogs as the expression of genes involved in inflammation or tissue hypoxia. We showed that VAT contained a higher amount of saturated FA (SFA) and conversely a lower amount of monounsaturated FA. We also showed that VAT would be more hypoxic and more inflammatory than SCAT as revealed by a higher HIF‐1α, HSL and cytokines (TNFα, leptin, IL‐1α and IL‐1β) expression in this first one. VAT could be more IR than SCAT due to its higher content in SFA, which are known to be deleterious and implicated in modulation of insulin signaling pathway. Moreover, according to a recent hypothesis, hypoxic conditions could also participate in the development of the inflammatory state and in turn in the development of IR. Consistent with the portal theory, an expansion of VAT could lead to a higher discharge of SFA (higher HSL expression) and inflammatory factors in portal vein, which could cause hepatic steatosis and IR.
Rosiglitazone Improves Insulin Sensitivity and Baroreflex Gain in Rats with Diet‐induced Obesity
Authors: Zhao Ding , Brooks Virginia L.
Published: June 2021

Obesity decreases baroreflex gain (BRG); however, the mechanisms are unknown. We tested the hypothesis that the impaired BRG is related to the concurrent insulin resistance. Male SD rats (~250 g) fed a high fat diet (HFD, 33% kcal fat) diverged into obesity‐prone (OP; top tertile of weight gain) and obesity‐resistant (OR; bottom tertile of weight gain) groups after 2 weeks. Subsequently, the OP and OR rats, as well as control (CON) rats fed a standard diet, were treated daily by gavage for 2–3 weeks with the insulin sensitizing drug, rosiglitazone (ROSI, 6 mg/kg), or its vehicle. Compared to conscious OR and CON rats, OP rats exhibited reduced BRG (in bpm/mmHg: OP, 2.9±0.1; OR, 4.0±0.2; CON, 3.9±0.2; n=5 per group; P<0.05) and insulin sensitivity (IS, in mg/kg·min: OP, 6.8±0.9; OR, 22.2±1.2; CON, 17.7±0.8; n=8 per group; P<0.05), and the decreases in IS and BRG were well correlated (r2=0.44; P<0.01). In OP rats (n=5), ROSI increased IS (to 16.0±1.5 mg/kg·min; P<0.01) and BRG (to 5.3±0.7 bpm/mmHg; P<0.05), but not in CON rats. In OR rats (n=5), ROSI improved (P<0.05) BRG (to 5.6±0.4 bpm/mmHg), but not IS. In addition, in OP and OR rats, for a given level of IS, ROSI produced further increments in BRG (ANCOVA, P<0.005). In conclusion, with diet‐induced obesity in rats, the reductions in BRG and IS share common mechanisms. Moreover, ROSI appears to improve BRG in rats fed a HFD by an additional mechanism unrelated to its effect to increase IS. (Supported by AHA and HL088552)
Rapid Death in Severe Gut Ischemia is Prevented By Parasympathetic Blockade
Authors: Penn Alexander , Schmid‐Schönbein Geert
Published: June 2021

Splanchnic arterial occlusion raises blood pressure (BP) in rats initially but within hours, even without reperfusion, BP falls irreversibly. Fatal pressure drops occur either over hours (slow) or in just minutes (fast). The fast BP drops occur without significant reduction of pulse pressure or pulse rate suggesting death is from neurogenic shock (i.e. dilation of peripheral blood vessels resulting in BP loss despite maintenance of cardiac contractility). Fast fatal pressure drops (FFPDs) occur more frequently and earlier if the rat is treated with intramuscular xylazine and glucose in the intestinal lumen, both stimulators of the parasympathetic nervous system (PNS). Thus we hypothesized parasympathetic inhibition by glycopyrrolate, a muscarinic anticholinergic, in intestinal ischemia could reduce incidence of rapid death. The results show that glycopyrrolate (1 mg/kg) significantly delayed onset of the fatal pressure drop (115±31 vs. 71±34 min post‐occlusion) and completely prevented FFPDs (0 of 6 vs. 5 of 8 animals with a fast death without glycopyrrolate), but not the slow form of pressure reduction. These results suggest that in severe intestinal ischemia, parasympathetic blockade prevents rapid pressure reductions, an observation that is consistent with a similar protection seen after vagotomy. Support: HL 67825, 76180, GM85072 and an unrestricted educational gift from Leading Ventures.
The molecular mechanisms of HepG2 apoptosis induced by Hedyotis diffusa
Authors: Wang Shu‐Qing , Kang Yu‐Ming , Wang Shu‐Qiu , Lv Da‐Ming , Qin Wen‐Bo , Li Dian‐Gang
Published: June 2021

The present study was undertaken to investigate the molecular mechanisms of inhibitory effects on proliferation and apoptosis inducing effect of Hedyotis diffusa (EHD) in HepG2. The viability and proliferation of HepG2 cell co‐culturing with EHD extraction were measured by MTT. Apoptosis frequency of HepG2 cell co‐culturing with EHD extraction was detected by FCM. The expression of bcl‐2 and caspase‐3 were detected by immunohistochemical analysis. Results: EHD inhibited the growth of HepG2 cells in time and dose‐dependent way, obvious morphological and biomolecular changes of apoptosis of HepG2 cells were detected after 48h EHD treatment evidenced by microscope observation and typical DNA ladder, EHD increases the apoptotic rates of HepG2 cells in dose‐dependent way after 48h EHD treatment, immunohistochemical analysis showed that EHD decreased bcl‐2 expression and increased caspase‐3 expression in dose‐dependent way after 48h EHD treatment. EHD inhibits the proliferation of HepG2 cells and induces apoptosis of HepG2 cells which is time‐dependent and dose‐dependent way. The expression of bcl‐2 and caspase‐3 was involved in this mechanism.
Laser‐speckle analysis of renal cortical perfusion – regional perfusion dynamics
Authors: Cupples William A , Waring Jennifer , Holstein‐Rathlou Niels‐Henrik , Chon Ki , Braam Branko
Published: June 2021

Tubuloglomerular feedback and a myogenic mechanism act on afferent arterioles to mediate autoregulation of renal blood flow (RBF) and their actions may extend beyond single nephrons. We tested for physiologically significant coupling among neighboring nephrons. Cortical surface perfusion was assessed by laser‐speckle perfusion imaging at 1 Hz. Time series from 5 regions of interest (ROI, ~0.5 × 0.5 mm) were extracted. RBF (Transonic 400) was systematically altered by manipulation of perfusion pressure, by captopril (−/+ ANG II), and by L‐NAME. Perfusion in the ROIs (units) was linear in RBF (slope = 1120 ± 63 units × min/mL, r2 = 0.94 ± 0.03, n=5). Power spectra of the ROI time series contain the same information as RBF spectra and spectra of all ROIs are very similar. Comparing adjacent to remotely located ROIs by spectra of difference series, by linear cross spectra, and by nonlinear cross bi‐spectra showed that coupling decreased with separation between ROIs. The cross bi‐spectral coupling index declined with separation of ROIs: adjacent = 0.269, medium = 0.170, remote = 0 during control (greater index = greater coupling). ANG II infusion increased the spread of coupling: adjacent = 0.133, medium = 0.034, remote = 0.014. Local coupling suggests that autoregulation may involve coordinate action of clusters of nephrons. Coupling may be regulated by ANG II.

Funded by Heart & Stroke Fdn of BC & Yukon, & Victoria Fdn
Development of damage to porcine renal arterial vascular anatomy and blood flow after cryoablation: acute to 2 weeks
Authors: Spaan Jos , Lagerveld Brunolf , van Horssen Pepijn , van den Wijngaard Jeroen , de la Rosette Jean , Laguna Pilar , Siebes Maria , Wijkstra Hessel
Published: June 2021

Aim

to better understand the acute and successive events of renal cryoablation.

Methods

In 20 anesthetized pigs renal cryoablation was applied for 20 minutes. Kidneys were divided into five groups with pig survival time after ablation of 20 min, 4 hrs, 2, 7 and 14 days after ablation. Before euthanasia, fluorescently labeled microspheres were intravenously administrated. The kidney was harvested, the main renal artery flushed, filled with a fluorescence dyed elastomere, frozen and processed in an imaging cryomicrotome. 2 stacks of 4000 images of 2000×2000 pixels where obtained. The 1st stack resulted in a 3D image of the arterial structure the 2nd stack in the 3D microsphere distribution matched to arterial structure.

Results

In the 20 min group, vascular structures with diam >200 μm remained in the ablated area but microspheres passing through were only found in surrounding tissue. No spheres were found within the ablated area. Ablated zone vascular structures disappeared completely after 1 week. In this and later groups, all microspheres in the surrounding tissue arrived by the non‐affected vessels.

Conclusion

Acute injury induced by cryoablation regards vessels smaller than 200 μm leaving the structure of larger vessels intact allowing blood flow to the surrounding tissue. It takes 1 week for complete destruction of vessels in the ablated area and bock blood flow.
Role of atypical TGF in the response of subtotal nephrectomy to ischemia
Authors: Singh Prabhleen , Kashkouli Ali , Blantz R , Thomson Scott C.
Published: June 2021

Subtotal nephrectomy (STN) leads to atypical and highly variable tubuloglomerular feedback (TGF) behavior in the residual nephrons in which the mean TGF response is zero (Singh P. AJP, 2009). Since TGF is a major hemodynamic mechanism causing fall in GFR after ischemia reperfusion (IR) injury, we examined the response of STN to IR.

STN and unilateral nephrectomy (UN) rats underwent IR 1 week after surgery. GFR (inulin clearance) was measured at 24 hours post IR. GFR fell by 75% in UN after IR and only 28% in STN, p=0.0001. Losartan, which paradoxically normalizes TGF in STN (Singh P, 2009) made STN susceptible to IR (p=0.001). Micropuncture experiments examined the magnitude and heterogeneity of individual nephron responses to IR. Mean SNGFR dropped from 52 to 40 nl/min in UN post IR, but did not change in STN (60 to 66 nl/min). The variance in SNGFR differed among groups (p=0.000), with STN+IR being most variable (Fig. 2). The Fmax test for raw variances in SNGFR was significant between UN+IR and STN+IR groups (172 vs. 1107), p<0.01.

Early STN kidneys are largely resistant to IR and we propose that the atypical TGF in STN contributes to this resistance. The effect of IR on SNGFR in STN parallels the effect of STN on TGF (fixed mean with high variability). Whether the high variance in SNGFR in STN+IR reflects the heterogeneous TGF responses prior to ischemia or the variable tubular injury after IR will need to be determined.

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Homocysteine induces epithelial‐to‐mesenchymal transition of podocytes through the activation of NADPH oxidase
Authors: Zhang Chun , Boini Krishna M , Xia Min , Hu Jun‐Jun , Li Pin‐Lan
Published: June 2021

Our previous studies have demonstrated that hyperhomocyteinemia (hHcys) induced glomerulosclerosis through the activation of NADPH oxidase (Nox). However, it remains unknown how homocysteine (Hcys) produces detrimental effects on podocytes. The present study tested the hypothesis that Hcys may induce epithelial‐to‐mesenchymal transition (EMT) in podocytes through the activation of Nox. Mouse podocytes were incubated with L‐Hcys, a pathogenic isoform of Hcys. It was found that L‐Hcys (80 μM) induced a dramatic increase in the expression of Nox subunits and subsequent superoxide (O2.‐) production (2.9 folds vs. control), which was accompanied by significantly decreased expression of slit diaphragm‐associated protein, P‐cadherin and zonula occludens‐1, a change consistent with loss of the epithelial feature. Meanwhile, L‐Hcys induced the expression of mesenchymal markers, fibroblast‐specific protein‐1 and α‐smooth muscle actin. Nox inhibitors significantly reversed these Hcys‐induced changes in podocytes. In functional studies, L‐Hcys was found to increase dextran permeability across podocyte monolayers by 1.9 folds, which was inhibited by Nox inhibitors. These results suggest that an EMT occurs in podocytes due to cellular oxidative stress during hHcys and that enhanced EMT may result in podocyte dysfunction leading to glomerulosclerosis (supported by NIH grants DK54927 and HL075316).
Effects of social environmental factors on malnutrition of 0–5 y children in China's poor areas
Authors: Zhang Bing , Zhai Fengying , Liu Aidong , Zhang Jiguo , Du Wenwen , Su Chang , Zhang Qiang
Published: June 2021

Malnutrition remains a health concern in China among ethnic minorities. This study used data from the China Children Nutrition Surveillance Survey (6000 in 2006 and 9000 in 2007/2008) to examine how social‐environmental factors affect nutrition and subsequently, can be used to create improved programs and policies for these populations. In‐depth dietary data coupled with socio‐demographic and anthropometric measurements were obtained from the minority children. The proportion of stunting and reduced weight for height and weight for age were examined. Zhuang children had the highest underweight (31%) while stunting was the highest in Miao children (34.0%–35.8%). Mongolian children had the lowest underweight (1.2%–2.4%) and stunting (4.2%–5.5%). Both underweight and stunting were the highest in children whose parents were illiterate (20%–24% and 28%–29% respectively) and the lowest in children whose parents graduated from colleges or universities (5%–6% and 1.2%–1.4% respectively). Both rates decreased as household income increased and were higher in children whose parents worked in farms than in children whose parents were clerical staff or manager. Children cared for by grandparents were particularly vulnerable to malnutrition. This study highlights these critical economic and demographic factors and feeds into poverty control and public health programs and provides both short‐term feeding and long‐term social policy guidance.
Nutritional status of displaced North Korean children
Authors: Lee Soo‐Kyung , Nam So Young , Heo Gyu Jin
Published: June 2021

Nutritional stress in early stage can have lasting impact on development and health. This study examined nutritional status of children born to North Korean parents, and currently living in South Korea. After IRB approval, a convenient sample of children (6 – 15 yr) was recruited. Children's height, weight, and percent body fat (InBody 720, Biospace) were obtained. Food situation at birth was assessed using Household Food Insecurity Access Scale Score with their parents through a questionnaire and an interview. Height and weight at the time of entry to South Korea were obtained from the health examination record. Children were born between 1994 and 2003 when famine was severe in North Korea. About half were born in North Korea; the other in China. More children born in North Korea (44.4%) were “food insecure” than those born in China (9.7%, ÷2=9.91, p<0.01). While 35% were stunted at entry, 8.5% were currently stunted after on average 2.2 years of stay. Only two percent of children born in “food secure” households were currently stunted, but 19.1% of children born in “food insecure” households were (÷2=4.46, p<0.05). Stunted children at entry tended to jump more weight percentiles, but not statistically significant. Nutritional status of the children improved, but overweight proportion was also increased. This work was supported by National Research Foundation of Korea Grant funded by the Korean Government (C00310).
Relationship Between Exhaled Na+ and the Diffusion Capacity of the Lungs for Carbon Monoxide (DLCO) and Alveolar‐Capillary Membrane Conductance in Healthy Humans
Authors: Wheatley Courtney M. , Cassuto Nicholas A. , Foxx‐Lupo William T. , Wong Eric C. , Delamere Nicholas A. , Snyder Eric M.
Published: June 2021

The regulation of Na+ in alveolar cells is important for maintaining lung fluid homeostasis and, therefore, lung function. We explored the relationship between the amount of Na+ in exhaled breath condensate (EBC) and DLCO and the components of DLCO, alveolar‐capillary membrane conductance (DM), and pulmonary capillary blood volume (Vc). We recruited 26 subjects (age=28±9yrs., ht.=173±11cm., wt.=71±13kg, body surface area (BSA)=1.8±0.2m2, FVC=97±15%, FEV1=95±14%, FEF25‐75=92±24% predicted, mean±SD) and collected EBC for 25 min. along with measures of DLCO, DM and Vc. The volume of EBC was 3.8±0.8ml, EBC Na+ was 2.7±1.7mmol/l, DLCO was 23±6ml/min/mmHg, DM was 35±9ml/min/mmHg, Vc was 58±26ml, mean±SD. There was a relationship between EBC volume and DLCO and DM (r=0.47 and 0.57, respectively, p<0.05). There was a positive correlation between DLCO, DM, Vc and EBC volume with BSA (r=0.76, 0.68, 0.69, and 0.42, respectively, p<0.05), a positive relationship between EBC Na+ and DLCO, DM and Vc (r=0.48, r=0.39, r=0.52, respectively, p<0.05) and a negative correlation between EBC Na+ and DM corrected for Vc (DM/Vc, r= −0.36, p=0.074). These results suggest that EBC volume and EBC Na+ are related to DLCO, DM, and Vc but that this is likely related to body size. EBC Na+ is inversely related to DM/Vc possibly suggesting EBC Na+ may be a surrogate measure of lung water.
Extent of shared presynaptic input to motor units of tongue and inspiratory intercostal muscles
Authors: Fregosi Ralph Frank , Rice Amber Dawn , Fuglevand Andrew J
Published: June 2021

Synchronous activation of motor units is attributed to common presynaptic input to motoneurons, and this is thought to increase the rate of rise of muscle force, and/or facilitate co‐activation of muscles. The inspiratory‐related drive to protrudor and retractor muscles of the tongue is associated with a rapid rate of rise of both EMG activity and force. Here, we examine the magnitude of synchronous discharge of co‐active motor unit pairs within genioglossus (GG, tongue protrudor), hyoglossus (HG, tongue retractor), and inspiratory intercostal (IC, rib cage expander) muscles in urethane‐anesthetized rats. We recorded from pairs of motor units that were spontaneously bursting under command of the respiratory central pattern generator. The strength of synchronous input to each pair was measured with cross correlation followed by the calculation of common input strength (CIS; frequency of synchronous action potentials in excess of those expected due to chance). CIS values for motor units within IC (N=9 pairs, 0.93 +/− 0.27) and tongue muscles (GG, 32 pairs, 0.83 +/− 0.11; HG, 41 pairs 0.67 +/− 0.13) were statistically equivalent. Across‐muscle CIS for tongue muscles was the same as the within muscle values (34 pairs, 0.55 +/− 0.1). CIS across GG and IC (10 pairs, 0.05 +/− 0.1) was less than within muscle values (P<0.01), while CIS between IC and HG was not (28 pairs, 0.29 +/− 0.1, P<0.05). In conclusion, the proportion of shared presynaptic inputs within and across the protrudor and retractor muscles of the rodent tongue is similar. In contrast, shared input to motor units of tongue and rib cage muscles is relatively low, which likely reflects drive from a different pool of premotor neurons.
Optogenetic Analysis of Area‐Specific Glial‐Neuronal Signalling
Authors: Tang Feige , Figueiredo Melina F. , Gourine Alex V , Teschemacher Anja G , Kasparov Sergey
Published: June 2021

We studied glia‐neuronal signalling in two brainstem areas, the retrotrapezoid nucleus (RTN) and the locus coeruleus (LC). RTN and LC neurons were visualized using adenoviral expression of DsRed2 under control of PRSx8 promoter. For optogenetic selective stimulation of astrocytes we have generated an adenoviral vector AVV‐sGFAP‐ChR2(H134R)‐Katushka1.3. We first patched AVV‐sGFAP‐ChR2(H134R)‐Katushka1.3‐transduced astrocytes and found that flashing 470 nm light induced precisely timed depolarisations (+18.8 ± 2.0 mV, n=7, p<0.001). We then patched RTN and LC neurons and stimulated adjacent astrocytes using light. This evoked long lasting depolarization of both RTN (+3.57 ± 0.5 mV, n=9, p<0.001) and LC neurons (+ 3.08 ± 0.33 mV, n=14, p<0.001). Responses of the RTN neurons were markedly reduced by the ATP receptor antagonist MRS2179 (10 μm), depolarisation +0.7mV, n=7, p<0.001). In contrast, neither MRS 2179 nor TNP‐ATP (10 μm) had any effect on of the responses in LC neurons (n=6, p=0.71 for MRS2179 and n=9, p=0.86 for TNP‐ATP). At the same time depolarisations in LC neurons were prevented by an NMDA receptor antagonist dAPV (50 μm, n=8, p<0.01) and AMPA receptor antagonist CNQX (10 μm, n=5, p<0.001). Therefore, glia‐neuronal information transfer occurs in area‐ and transmitter‐dependent manner.