bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronic heart failure and nitrate supplementation: Impact on skeletal muscle vascular control in exercising rats
Authors: Ferguson Scott , Holdsworth Clark , Wright Jennifer , Hageman Karen , Musch Timothy , Poole David
Published: June 2021

Chronic heart failure (CHF) results in central and peripheral derangements that ultimately reduce skeletal muscle O2 delivery and impair exercise tolerance. Dietary nitrate (NO3‐) supplementation improves skeletal muscle vascular function and improves tolerance to exercise. We tested the hypothesis that NO3‐ supplementation would elevate exercising skeletal muscle blood flow (BF) and vascular conductance (VC) in CHF rats. Myocardial infarction (MI) was induced (coronary artery ligation) in young‐adult male rats. After 21‐days of recovery, rats randomly received NO3‐ rich beetroot juice (CHF+BR, n=10) or a placebo (CHF, n=10). Mean arterial pressure (MAP, carotid artery catheter) and skeletal muscle BF (radiolabeled microspheres) was measured during treadmill exercise (20 m/min, 5% grade). CHF parameters (MI size, CHF: 29 ± 3, CHF+BR: 33 ± 4%, LVEDP, CHF: 18 ± 2, CHF+BR: 18 ± 2 mmHg) and exercising MAP (CHF: 131 ± 3, CHF +BR: 128 ± 4 mmHg) were not different (P<0.05) between groups. Total hindlimb skeletal muscle BF (CHF: 95 ± 5, CHF+BR: 116 ± 9 ml/min/100g) and VC (CHF: 0.75 ± 0.05, CHF+BR: 0.90 ± 0.05) were greater (P<0.05) in BR supplemented rats. The increases in BF and VC (P<0.05) were found preferentially in muscles and muscle parts containing 蠅70% type IIb + d/x muscle fibers which resulted in a ~22% increase in total skeletal muscle BF and a 20% increase in total VC during exercise. These results provide strong evidence that dietary NO3‐ supplementation improves skeletal muscle vascular function during exercise in rats with CHF and suggest that BR may provide a novel therapeutic modality for the treatment of CHF.
NIH HL‐108328
Extended Daily Exercise is the Key to Blood Pressure and BMI Reductions in High School Students
Authors: Hayes Shawn , Irvin Erica
Published: June 2021

Objective

Demonstrate if combining physical education (PE) and health classes into an extended daily single class model will result in decreases in blood pressure and BMI in overweight and obese students.

Methods

At a high school in Portland, OR, HealthCorps and school staff developed and implemented the Fit2Live and Learn (F2LL) program, an integrative approach to health and PE. This was an adjunct to the wellness program run by HealthCorps in the school. The prior PE program was changed from a class that met every other day to a class that met daily for 90 minutes, covering two class periods. Students received credits for both Health and Physical Education courses. The program combined its traditional Health and PE classes into an experiential integrative approach to health concepts. The F2LL program was a school‐year long practice of optimal exercise, healthy eating and mental strength habits for students. We measured BMI, blood pressure, heart rate and percent body fat as measured by bioelectric impedance analysis.

Results

In a group of 43 students, systolic blood pressure was reduced from 121 to 111 mm Hg (p<0.05) over the course of four visits (eight months). In a subset of those students who were either overweight or obese (n=14), systolic BP decreased from 128 to 117 mm Hg (p<0.05). Diastolic blood pressure and heart rate did not change significantly in any group. BMI was reduced in overweight and obese freshman (BMI>25) from 33.1 to 32.2 kg/m2 and in obese freshman (BMI>30) 37.8 to 37.2 kg/m2. There was a concomitant decrease in percent body fat by 1.4%.

Conclusion

The F2LL program combined with HealthCorps' program emphasizing nutrition, mental resilience and physical activity, resulted in significant decreases in blood pressure and BMI in the freshman PE class at one Portland public high school.
Inhibitory Regulation of Skeletal Muscle Shivering
Authors: Morrison Shaun
Published: June 2021

Skeletal muscle shivering thermogenesis contributes to the cold‐defensive maintenance of core body temperature and to the elevated body temperature during fever. The thermoregulatory reflex pathway through which skin and core cooling, or injection of prostaglandin E2 into the preoptic area of the hypothalamus, leads to activation of skeletal muscle shivering has been described (J Physiol 589.14: 3641–3658, 2011). Although this pathway influences the discharge of alpha‐motoneurons in the ventral horn, rather than sympathetic preganglionic neurons in the intermediolateral nucleus, it is remarkably parallel to the thermoregulatory pathway mediating cold‐defensive activation of brown adipose tissue (Cell Metabolism 19: 741‐756, 2014). To determine if this similarity extends to the central and vagal afferent inhibitory regulation of skeletal muscle shivering, neurons in the paraventricular hypothalamus, in the nucleus of the tractus solitarii, or in the ventrolateral medulla were activated; or electrical stimuli were applied to afferents in the cervical vagus nerve, during cold‐ or PGE2 injection‐evoked increases in masseter, neck and gastrocnemius muscle EMGs in Inactin‐anesthetized rats. Activation of neurons in each of these regions, or vagus nerve stimulation elicits a marked inhibition of cold‐evoked and PGE2‐evoked brown adipose tissue sympathetic outflow and thermogenesis. Overall, the results, indicate strong parallels between the inhibitory regulation of shivering and brown adipose tissue thermogenesis and energy consumption. The specific physiological stimuli for, and the synaptic integration sites supporting these inhibitions of shivering remain to be determined. Supported by NIH grant NS40987.
Electrical stimulation of the cervical vagus nerve protects against renal ischemia/reperfusion injury
Authors: Abe Chikara , Inoue Tsuyoshi , Okusa Mark , Guyenet Patrice
Published: June 2021

The inflammatory reflex acts via connections between the CNS and lymphoid organs, inc the spleen, to suppress the production of inflammatory cytokines. Such reflex can be elicited by electrically stimulating the cervical vagus nerve (VN) or merely its peripheral end. Vagal preganglionic neurons (VPGNs) do not appear to directly innervate the spleen, therefore an excitatory synaptic connection between vagal preganglionic efferents and splenic nerve efferents has been proposed. To examine this, we recorded splenic sympathetic nerve activity (SNA) and stimulated the uncut left VN in anesthetized rats. Electrical stimulation of the uncut VN (0.1 mA, 1 ms, 1 Hz) evoked a robust response with two distinct activation peaks (latencies: 109 ± 2 and 186 ± 5 msec). Stimulating the peripheral end of the cut VN evoked no response confirming the absence of detectable synaptic connection between vagal efferents and splenic nerve (Martelli et al. Auton Neurosci 2014). We also examined whether VN stimulation reduces ischemia/reperfusion injury (IRI) in mice. We electrically stimulated the uncut left cervical VN (0.1 mA, 5 Hz, 10 min), its peripheral end or its central end in 3 groups of mice 24 hrs before IRI (26 min). The three stimulation modalities produced equal protection against IRI as judged by a large and significant reduction of plasma creatinine concentration measured 24 hrs after ischemia.

Conclusions

stimulating either end of the cut vagus nerve protects the kidney from IRI, presumably by reducing inflammation. Proximal vagal stimulation may cause anti‐inflammation by increasing splenic SNA. How peripheral VN stimulation produces renal protection is unclear.
Norepinephrine (NE) Increases Production of Superoxide (O2• ‐) in Cultured Peripheral Blood Mononuclear Cells (PBMCs) and Splenocytes Isolated from Rats
Authors: Magee Joe , Deo Shekhar , Fadel Paul , Heesch Cheryl
Published: June 2021

Physiological/pathophysiological states with increased sympathetic nerve activity (SNA) are associated with oxidative stress. It is known that increased O2• ‐ in specific brain regions results in increased efferent SNA. Recently we found that NE increased intracellular O2• ‐ production (Dihydroethidium, DHE) and mRNA for NADPH oxidase (NOX‐2) subunits in cultured PBMCs from humans suggesting elevated SNA may increase systemic O2• ‐ production. Current experiments tested whether the rat is a good experimental model of humans to further study the interaction between sympathoexcitation and PBMC‐derived O2• ‐. Primary PBMCs and splenocytes were isolated from male rats and incubated at 37°C for 36 hr with either vehicle (Veh), 50 pcg/ml, 50 ng/ml, or 50 µg/ml NE. Similar to human PBMCs, relative to Veh, NE increased intracellular O2• ‐ production in rat PBMCs (50 µg/ml NE = 11± 5 fold; P< 0.05) and tended to increase mRNA for NOX‐2 subunits (50 ng/ml NE: gp 91phox = 1.8 ± 0.4; p22phox = 1.6± 0.5). NE also increased O2• ‐ in rat splenocytes (50 µg/ml NE = 11± 6 fold; P< 0.05). Thus, results in rat PBMCs and splenocytes are similar to human PBMCs, and are consistent with a positive feedback system whereby increased NE promotes increased O2• ‐ in circulating PBMCs which in turn could activate CNS sites to promote further increases in SNA. Using the rat as a model, future experiments will evaluate a potential role of circulating PBMCs on activation of brain regions involved in the control of sympathetic outflow. R01 HL091164
Carotid Chemoreceptor Desensitization Improves Baroreflex Control of Blood Pressure During Hypoxia in Humans
Authors: Mozer Michael , Joyner Michael , Curry Timothy , Limberg Jacqueline
Published: June 2021

There are known interactions between the chemoreflex and baroreflex. The purpose of the present investigation was to examine the contribution of the carotid body chemoreceptors to changes in baroreflex control of blood pressure with exposure to hypoxia. Low‐dose dopamine blunts carotid body afferent activity and can thus be used to examine the contribution of the carotid chemoreceptors to reflex responses during hypoxia.

Hypothesis

Spontaneous cardiac baroreflex sensitivity (scBRS) will be reduced with hypoxia and this effect will be blunted when the carotid chemoreceptors are desensitized with low‐dose dopamine.

Methods

Seven subjects (4M/3F) completed 2 visits randomized to IV dopamine (individualized dose shown to result in a nadir hypoxic ventilatory response, 1‐4 μg/kg/min) or placebo (saline). Subjects were exposed to 5‐min normoxia (99±0% SpO2), followed by 5‐min hypoxia (83±2%SpO2). Blood pressure (intra‐arterial catheter) and heart rate (ECG) were measured continuously and sCBRS was assessed by spectrum analysis. The relative (%) change in sCBRS with hypoxia [(Hypoxia‐Normoxia)/Normoxia x 100)] was compared between dopamine and placebo.

Results

scBRS was reduced with hypoxia (saline p<0.01; dopamine p<0.01). The fall in scBRS with hypoxia was blunted with dopamine (saline: ‐58±7 %, dopamine: ‐42±9 %, p=0.02).

Conclusion

These data are consistent with a reduction in scBRS with chemoreceptor activation. Furthermore, we show this effect is partially mediated by the carotid body chemoreceptors, given the fall in scBRS is attenuated when the chemoreceptors are desensitized with low‐dose dopamine.

Funding NIH DK090541 (Joyner)
Endogenous Erythropoietin is a Sex Specific Respiratory Stimulant in Newborn and Adult Mice.
Authors: Ballot Orlane , Joseph Vincent , Soliz Jorge
Published: June 2021

We hypothesized that endogenous brain Erythropoietin (Epo) is a sex‐specific respiratory stimulant in newborn (10 days old) and adult (3 months) mice. Mice received an intracisternal injection of soluble Epo receptor (sEpoR – antagonist of EpoR) or control. 24 hours after injection, we used whole body plethysmography to record respiratory frequency (fR), tidal volume (VT), and minute ventilation (VE=fRxVT), O2 consumption (VO2) and CO2 production (VCO2) under normoxia and exposure to moderate (12‐10% O2) and severe hypoxia (6% O2) – 10 minutes each. In normoxia, sEpoR decreased VE in adult and newborn mice, but this effect was sex‐specific as sEpoR decreased fR in females and Vt in males. The ventilatory response to moderate hypoxia (assessed as VE/VO2 or VE/VCO2) is decreased in newborn male and female mice after injection of sEpoR, but in adult mice this effect was present only in males. During severe hypoxia, newborn male and female mice treated with sEpoR show signs of respiratory depression and asphyxia (gasping). We conclude that endogenous Epo is a potent endogenous respiratory stimulant in newborn and adult mice, that sex‐specific effects are present under normoxic conditions in newborn and adult mice, and that under hypoxic exposure, sex‐specific effects are present only in adult mice. Funded by CIHR (mop: 130258).
Targeting Reversible Lysine Modifications
Authors: Cole Philip
Published: June 2021

Reversible protein lysine modifications including acylation and methylation have been recognized as critical to the regulation of cell growth, differentiation, and gene expression. However, many aspects of their function are poorly understood. We will discuss several chemical approaches that our lab is taking to the functional analysis of lysine acylation and demethylation including inhibitor design strategies and protein semisynthesis. In combination with enzymologic, biophysical, and cellular strategies, these chemical approaches have offered new insights into the roles of lysine post‐ translational modifications in normal and disease states.
Diversifying Training Options for Undergraduate and Graduate Students to Support Industry Careers
Authors: Wallert Mark
Published: June 2021

The demand for employees with skills in STEM has never been higher. Likewise, the diversity of career options available to these employees has never been greater. Traditionally, the primary career path for individuals interested in advanced STEM careers was to obtain a Ph.D. and pursue a career in academia. Today, 67% of biomedical Ph.D.s are employed in careers outside of academia. This diversity of careers extends to all levels of the STEM education spectrum. The Bioscience Industry sector in the United States is a major employer of individuals trained in biochemistry and biotechnology areas. This industry sector currently employs over 30% of Ph.D.s in the life and physical sciences. While a majority of the position in the Bioscience Industry requires a Bachelor's degree or higher, success in these careers requires technical knowledge and skill sets that are not commonly taught in undergraduate and graduate programs. No matter the educational level, it is no longer sufficient to focus on training students to have the knowledge and skills to be competent scientists. In preparing students for industry careers this goes beyond expanding the focus on non‐technical or soft skills. Preparing students for industry careers now requires courses and mentoring programs that demonstrate the range of career options and includes courses that comprise a range of supplemental technical skills related to functioning in a highly regulated industry. The additional skill sets industry is looking for includes work in quality systems, good laboratory and good manufacturing practices, animal care and use, and regulatory compliance. This presentation will focus on the need for expanded training options to meet the need for industry employees and provide examples of successful programs and program changes that meet these needs.
Consuming 2 Eggs per Day Results in Reduced Glycemic Load, Lower Intake of Sugar and Increased Satiety Compared to Oatmeal Consumption in a Young Healthy Population
Authors: DiMarco Diana , Missimer Amanda , Vergara‐Jimenez Marcela , Kretzmer Rae , Soto Ingrid , Fernandez Maria‐Luz
Published: June 2021

The effects of 2 eggs/day or 1 packet of oatmeal/day on plasma ghrelin and visual analog scales (VAS) were investigated in a young healthy population of men and women (23.3 ± 3.1 years) to determine which breakfast was more effective in modulating satiety. Three‐day dietary records were evaluated to determine the effects of each breakfast on daily macronutrient intake and glycemic load. Fifty participants were allocated to consume either eggs or oatmeal daily for 4 weeks. Following a 3‐week washout period, participants were allocated to the alternate treatment for an additional 4 weeks. During the egg period, participants consumed more fat (p < 0.01), dietary cholesterol (p < 0.0001), monounsaturated fat (p < 0.025), and less carbohydrate (p < 0.0005). In addition, during the egg period there was a 25% reduction in total sugar intake (p < 0.05) and a 16% reduction in glycemic load (p < 0.05). Although plasma ghrelin concentrations were not different between groups, ghrelin during the egg period was negatively correlated with feeling full before breakfast (‐0.472, p < 0.05). No correlations were found during the oatmeal period. Finally, VAS indicated that participants felt more full (p < 0.05) and were less likely to want to consume sweet foods (p < 0.05) following the egg period. These data suggest that an egg breakfast is beneficial in reducing appetite, decreasing sugar consumption, and increasing satiety during the day
Overtime Growth and Spatial Distribution of Fast Food Industry in China during 2005‐2012
Authors: Cheng Xi , Wang Youfa , Xue Hong , Qu Weidong
Published: June 2021

Objectives

Fast food (FF) industry and obesity rate have increased rapidly in China the past 2 decades. This study examined overtime growth and spatial distribution patterns of FF industry in China and the key social economic factors that might contribute to the growth.

Methods

Using government reported longitudinal data from 21 provinces and cities in China for 2005‐2012 we visualized temporal and geographic distributions of FF outlets using ArcGIS. We conducted cross‐sectional and longitudinal spatial analysis to assess associations between macroeconomic conditions, population dynamics, and the growth and distributional changes of FF industry (assessed by number of FF outlets and FF revenue) across China.

Results

FF industry grew faster in southeast coast areas (more economically developed) since 2005 than other regions. FF industry development (FF outlets and revenue) was: 1) highly correlated with Gross Domestic Product (GDP, or per capita GDP) (Person correlation coefficient r =0.65 and 0.67 for FF outlets and revenue, respectively; 2) highly correlated with per capita disposable income for urban residents, r=0.70 (FF outlets) and 0.76 (FF revenue); 3) moderately correlated with urban population, r=0.38 (FF outlets) and 0.36 (FF revenue); 4) not correlated with increase of population size (r=0.10 of FF outlets, 0.05 of FF revenue). The mean center of FF industry shifted westward during 2005‐2012 with mean center of GDP moved in the same direction, while mean center of population shifted eastward.

Conclusions

FF industry grew rapidly in China during 2005‐2012 with large temporal and spatial variations. Development of local economy has fueled FF growth.

Funding: NIH U54 center grant, HD070725
Higher Red Blood Cell n‐3 Fatty Acid Composition Prospectively Relates to Lower Depressive Symptomatology
Authors: Bigornia Sherman , Tucker Katherine , Falcon Luis , Harris William
Published: June 2021

Introduction

Puerto Rican adults report greater levels of depressive symptomatology compared to other Latino and non‐Latino groups. Dietary n‐3 fatty acid intake may improve symptoms of depression, but results are inconsistent. We examined the prospective relationship between biomarkers of n‐3 fatty acid consumption and depressive symptomatology.

Methods

Cohort (Boston Puerto Rican Health Study) of 1,067 participants with mean age 57 y (SD: 8) and 72.3% female. Degree of depressive symptomatology was obtained at baseline and 2 y (IQR 2.0‐2.2) using the Center for Epidemiology Studies Depression Scale (CES‐D). We measured red blood cell (RBC) membrane fatty acid composition at baseline. N‐3 fatty acid index was defined as the sum total of eicosapentaenoic and docosahexaenoic acid expressed as a percent of total RBC fatty acid content.

Results

In multivariate models, n‐3 fatty acid index was inversely associated with 2 y CES‐D score , adjusting for baseline score [mean (95% CI); Q1 19.9 (18.6, 21.2) vs. Q4 18.3 (17.0, 19.6); P‐trend<0.05, Table Model 5]. Results remained consistent after accounting for saturated, trans‐, n‐6 polyunsaturated, or monounsaturated fatty acid content (P‐trend=0.03‐0.08) or excluding those who changed n‐3 supplementation from baseline (P‐trend<0.05).

Conclusion

Using an objective measure of n‐3 fatty acid intake, our data suggest that n‐3 fatty acid consumption may be beneficial in the management of depressive symptomatology.

Table. Prospective relationship between baseline n‐3 fatty acid index and CES‐D score at 2 y follow‐up (n=1067)

Baseline n‐3 RBC fatty acid index

Q1 3.1±0.5%
Q2 4.0±0.2%
Q3 4.7±0.2%
Q4 6.0±0.9%

n=266
n=267
n=267
n=267

Model
Covariates
mean (95%CI)
mean (95%CI)
mean (95%CI)
mean (95%CI)
P‐trend

1
baseline CES‐D score, anti‐depressive medication use, time between visits
20.4 (19.2, 21.6)
18.7 (17.5, 19.9)
17.7 (16.5, 18.9)*
17.7 (16.4, 18.9)*
<0.001

2
+ sex, age, BMI, smoking status
20.0 (18.8, 21.3)
18.5 (17.3, 19.8)
17.8 (16.5, 19.1)*
18.2 (16.8, 19.5)
<0.05

3
+ high school education status
20.0 (18.8, 21.3)
18.5 (17.3, 19.7)
17.8 (16.5, 19.1)*
18.2 (16.9, 19.6)
<0.05

4
+ physical activity score
20.0 (18.8, 21.3)
18.5 (17.3, 19.7)
17.8 (16.5, 19.1)*
18.3 (17.0, 19.6)
<0.05

5
+ Healthy Eating Index 2005 score excluding healthy oil component
19.9 (18.6, 21.2)
18.4 (17.1, 19.6)
17.7 (16.4, 19.0)†
18.3 (17.0, 19.6)
<0.05

†P=0.05 to <0.1, *P<0.05 compared to Q1
Cardiac Kids Club: A Childhood Obesity Prevention Afterschool Intervention for Elementary School Students
Authors: Spence Marsha , McDonald Aneisa , Perry‐Burst Carolyn
Published: June 2021

The objective of this study was to assess pre‐ and post‐intervention dietary intake measures, physical activity levels, and body mass index (BMI) of students enrolled in a 10‐week (2 sessions per week) afterschool obesity prevention program. This one group pretest‐posttest design used a validated dietary intake survey, fitness measures using FitnessGram , and height and weight measurements taken by trained research assistants and school health personnel. The program was conducted in 6 elementary schools with 134 participants in grades 4 and 5; 111 participants (82.8%) completed all study components. Sixty‐four of the participants (57.7%) were overweight or obese (age‐ and sex‐specific BMI>85th percentile) at baseline. Mean BMI among overweight and obese participants significantly decreased (p=0.02) from 94.77 (SD 4.41) to 93.80 (SD 5.89), while BMI among normal weight participants did not significantly decrease (p=0.44). Dietary intake measures were not significantly improved from pre to post. Fitness measures (curl up, trunk lift, right and left sit and stretch, pushups, and mile run) were significantly improved among all participants (p<0.001); these measures were also significantly improved among overweight and obese participants (p<0.01). Although dietary intake measures were not improved, the program was successful in improving BMI among overweight and obese participants and fitness levels improved for all participants, including overweight and obese participants.
Accuracy of Consumers' Ability in Identifying Whole Grains Foods: Implications for Policy Change
Authors: Chea Molika , Foster Jaime , Mobley Amy
Published: June 2021

Americans continue to fall short on meeting recommendations for whole grain foods possibly because of the difficulty in identifying them. The objective of this research was to assess the accuracy of consumers' ability in identifying common whole grain foods and to determine if the accuracy differed by demographic characteristics. As part of a nutrition display, adults (n=349) viewed 11 foods consisting of 5 whole grains and 6 refined grain foods and then completed a questionnaire to identify what foods were whole grain. Descriptive statistics and logistic regression analysis were conducted. The mean (SD) age was 43.9 (17.9) years and the majority of participants were female (60%), white (86%), and had a Bachelor's degree or higher (63%). Less than half (43%) of participants were able to correctly identify all 5 whole grain foods. The whole grain foods identified incorrectly most often were popcorn (38%) and whole grain crackers (20%) while white rice (28%) and wheat bread (17%) were often incorrectly identified as whole grains. Participants who were non‐Hispanic (OR=2.996, P=.05), white (OR=5.829, P<.001), and who had more than a Bachelor's degree (OR=2.19, P=.05) were more likely to correctly identify all 5 whole grain foods. These results indicate that the ability to identify whole grain foods may be a barrier to consuming adequate amounts especially for some subpopulations. With a current lack of universal whole grain food labeling, these results also have implications for policy change.
Dietary Arginine Requirements are Dependent on the Rate of Citrulline Production in Mice
Authors: Marini Juan , Didelija Inka
Published: June 2021

In many species, including humans, arginine (Arg) is considered a semi‐essential amino acid because under certain conditions endogenous synthesis cannot meet its demand. The requirements of Arg for growth in mice are ill defined and seem to vary depending on the genetic background of the animals. For this reason, Institute of Cancer Research (ICR) and C57BL/6J (BL6) mice were fed diets with increasing Arg content between 24 and 42d of life to determine the Arg requirements for growth. 'De novo' Arg synthesis and the production of its precursor, citrulline (Cit), were measured using stable isotopes. ICR mice were heavier than BL6 mice (12.1±0.20 vs. 8.7±0.11 g, P < 0.001) at weaning (d21) and displayed a greater growth rate (0.66±0.04 g/d and 0.46±0.03 g/d, P < 0.001). Whereas ICR mice grew at the same rate regardless of the Arg content of the diet (P = 0.80), BL6 mice showed a reduction in growth rate when fed the diet devoid of Arg (Arg sufficient diet 0.46±0.03 vs. Arg free diet 0.25±0.02 g/d, P < 0.001). Breakpoint analysis showed that on average, BL6 mice require 2.32±0.39 g Arg/kg diet to maximize weight gain. A reduced expression of ornithine transcarbamylase in the small intestine of BL6 mice (0.15±0.0 vs ICR 1±0.2 arbitrary units, P < 0.001) was responsible for the lower rate of Cit production observed in BL6 mice (96±5 vs ICR 123±9 µmol•kg‐1•h‐1, P < 0.002), which translated into a reduced 'de novo' Arg synthesis (P < 0.001) and explains why this strain has a requirement for Arg. Our data indicates that variability in the production of Cit and endogenous synthesis of Arg determined the need for dietary Arg to meet the requirements for growth. This indicates that in mice Arg is an essential amino acid for growth, at least for some genetic backgrounds.
Development of 3D In Vitro Models of Nerve and Skin for Disease, Disorder and Testing Studies
Authors: Haycock John
Published: June 2021

Peripheral nerve injuries are common and the high level of cell death and lack of coherent orientation of regenerating axons without surgical intervention has lead to therapies using nerve guidance conduits (NGCs). NGCs are hollow tubes that act as a physical guide between the proximal and distal stumps, bridging the gap of the injury. They can be made from a variety of synthetic or natural materials and can incorporate cells to improve guidance. Current objectives focus on methods for improving NGC design and span: 1) the synthesis and characterisation of scaffolds for controlling the direction of neuronal and Schwann cell growth; 2) surface chemical modification for improving neuronal and Schwann cell integration; 3) 3D printing methods for making NGCs from degradable polymers and the development of 3D in vitro models of peripheral nerve. This work extends through to 3D skin models, where parallel techniques in scaffold fabrication, keratinocyte and fibroblast culture and imaging / detection methods have been developed as a basis for irritation and sensitization testing, with inflammatory marker analysis as an alternative to standard animal tests.
Validation of Stable Isotope Ratios as Biomarkers of Meat, Fish, and Soda Intake
Authors: O'Brien Diane , Votruba Susanne , Krakoff Jonathan
Published: June 2021

Objective

The objective of our study is to test whether stable isotope ratios of carbon (13C/12C) and nitrogen (15N/14N) can distinguish intakes of fish, meat, and soda.

Methods

Sixteen men (42±9 yrs, BMI 26.4±3.8 kg/m2) were inpatients at the NIDDK in Phoenix, AZ, for 14 weeks. Dietary effects on plasma and RBC 13C and 15N were tested using a factorial design, with three intake variables (meat/fish/ soda) present at two levels (present/absent), against a common, background diet (50%cho, 30%fat, 20%pro). Blood was drawn biweekly and hair was sampled post diet intervention. Measurements were conducted via continuous flow IRMS. Plasma and RBC data were analyzed with factorial ANCOVA, including week as a covariate and diet X week interactions. Only significant main effects are presented here. Hair data were analyzed with factorial ANOVA.

Results

The carbon isotope ratio of plasma was elevated when diets included soda (ß = 0.22 ± 0.05, P < 0.0001) and meat (ß = 0.19 ± 0.05, P = 0.0001). The nitrogen isotope ratio of plasma was elevated when diets included fish (ß = 0.28 ± 0.03, P < 0.0001) and meat (ß = 0.22 ± 0.03, P < 0.0001). Results were similar for RBC. In hair, the carbon isotope ratio was elevated when diets included soda (ß = 0.77 ± 0.3, P = 0.02), and the nitrogen isotope ratio was elevated when diets included fish (ß = 0.4 ± 0.2, P = 0.02) and meat (ß = 0.5 ± 0.2, P = 0.005).

Conclusions

These results indicate that natural enrichment of 13C/12C and 15N/14N in plasma, RBC, and hair may serve as biomarkers for meat, fish and soda intake, and establish a role for stable isotopes in distinguishing longer term dietary patterns. This research was supported through intramural funds of the NIDDK.
The Relationship of Breast Milk Intake as Assessed with Deuterium Dilution on Growth and Body Composition of Infants in Jamaica
Authors: Whyte Sherine , Royal‐Thomas Tamika , Badaloo Asha , Reid Marvin
Published: June 2021

Background

The WHO recommends exclusive breastfeeding up to 6 months of age. Jamaica is a lesser developed country which is undergoing an epidemiological transition. Recent evidence suggests a relationship between breastfeeding, infant growth and chronic diseases in later life.

Objective

This study sought to determine the relationship between breast milk consumption with the pattern of growth and body composition in Jamaican infants at 3 months.

Method

A longitudinal and observational study including 35 child‐mother pairs, recruited from the post natal ward of the University Hospital of the West Indies. Body composition and breast milk intake were measured at 6 weeks using the mother to child deuterium dilution method. Standard anthropometric methods were used to assess growth at 6 weeks and 3 months.

Results

Thirteen (37%) of the women were found to be exclusively breastfeeding with mean breast milk consumption of 956 ± 304 g day‐1. This contrasted with 22 women who were not exclusively breastfeeding with mean consumption of 704 ± 349 g day‐1 of milk intake and 526.7 ± 512.7 g day‐1of non‐milk intake. In the 35 infants, higher breast milk intake was positively associated with higher length, weight and fat free mass (p=0.01) at both time points. Exclusive breastfed infants were taller (p=0.02) and had larger head circumference (p=0.03) at 6 weeks and 3 months when compared with mixed fed infants.

Conclusion

The data suggests that exclusive breastfed infants are less likely to be shorter than mixed fed infants. Infants who had greater intake of breast milk had a higher proportion of lean body mass. The effect of breast milk on length and lean tissue deposition could be related to less risk of developing obesity later in life.
Effect of High Protein Consumption on Markers of B6 Status in a Rodent Model of Moderate Pyridoxine Deficiency
Authors: Raposo‐Blouw Sara , Mayengbam Shyamchand , House James
Published: June 2021

Pyridoxal‐5‐phosphate (PLP) is the active form of pyridoxine (PN; B6). Increasing protein intake may affect B6 status by increasing PLP‐dependent enzymes in amino acid metabolism. These impacts may be more pronounced during moderate B6 deficiency, which is observed in 25% of North Americans. To this end, we examined the impact of changing the dietary carbohydrate:protein ratio in rodents consuming recommended vs. moderately deficient intakes of PN‐HCl, on plasma markers of B6 status. Weanling male Sprague‐Dawley rats (n=8/group) were randomized to one of four dietary groups for five weeks. A two factorial design used two levels of B6 (marginally deficient (MD): 0.7 vs. adequate (A): 7.0 mg PN‐HCl/kg diet), and two defined ratios of carbohydrate to protein: 60%: 20% (AIN‐93 standard; NP); and 40%: 40% (high protein diet; HP), with dietary fat held constant. Plasma B6 vitamers, including PN, pyridoxal (PL), PLP, and 4‐pyridoxic Acid (PA) were analyzed by reverse‐phase high‐pressure liquid chromatography in dark conditions. Decreasing dietary B6 intake significantly depressed all plasma B6 vitamers. Increasing dietary protein intake significantly depressed plasma PN (A‐NP=235; A‐HP=203; MD‐NP=181; MD‐HP=90 nM; SEM =21.8 nM). There were no significant interactions evident. Other markers of B6 status, including plasma homocysteine, were not significantly impacted. The current data provide evidence of an increased conversion of PN to PLP in the face of an increased dietary protein load. However, under moderate B6 deficient conditions, consuming high amounts of protein similar to the upper acceptable macronutrient distribution range does not significantly exacerbate B6 deficiency.
Unmetabolized Folic Acid by Sources of Folic Acid Intake Among US Adults in the National Health and Nutrition Examination Survey 2007‐2008
Authors: Qi Yan Ping , Crider Krista , Tinker Sarah , Berry Robert
Published: June 2021

Circulating unmetabolized folic acid (UMFA) has generated great interest; however, its biological effects are unclear. The prevalence of UMFA by all sources of folic acid intake from foods and supplements has not been assessed among a nationally representative sample of US adults. Using cross‐sectional data from the National Health and Nutrition Examination Survey (NHANES) 2007‐2008, we examined the prevalence of any detectable circulating UMFA and UMFA >1 nmol/L among US adults >19 years (n=1,496), categorized into mutually exclusive groups according to sources of folic acid consumption: enriched cereal grain products (ECGP) only, ECGP + ready‐to‐eat cereals (RTE), ECGP + supplements (SUP), and ECGP+RTE+SUP. Intake was self‐reported and assessed using 2‐24 hour dietary recalls. We used chi‐square tests in SUDAAN to compare the prevalence across different exposure groups adjusting for sex, age, and race/ethnicity. Compared to those consuming ECGP only, the consumption of RTEs and/or supplements with folic acid was positively associated with detectable circulating UMFA and UMFA >1 nmol/L. The proportion of adults with detectable UMFA among ECGP only, ECGP+RTE, ECGP+SUP, and ECGP+RTE+SUP was 95%, 97%, 96%, and 99%, respectively (p=0.0447). The proportion of adults with UMFA >1 nmol/L among these same groups was 18%, 32%, 50%, and 62%, respectively (p<0.0001). Among adults who consumed supplements containing folic acid, the prevalence of UMFA >1 nmol/L was 47% and 68% among those consuming <400 and >400 µg folic acid/day from supplements, respectively (p=0.0014). These analyses indicate that the prevalence of circulating UMFA was high among US adults post‐folic acid fortification.
Is Nutrition Assistance Program Participation or Food Security Status Associated with Parental Feeding Style or Child Body Mass Index
Authors: Smith Jaime , Adamsons Kari , Vollmer Rachel , Mobley Amy
Published: June 2021

This pilot study including parents of 3‐5 year old children investigated 1) the association of household food security status with parental feeding style, 2) the association of nutrition assistance program participation with parental feeding style and, 3) the association of nutrition assistance program participation and/or food security status with child body mass index (BMI). Low income parent dyads (n=52) participated in individual interviews including the United States Department of Agriculture's Household Food Security Questionnaire, Caregiver Feeding Style, and a demographic questionnaire. Height and weight were measured and BMI z‐scores (child) were calculated. Linear and multinomial logistic regressions were conducted. Food security scores of mothers and fathers were not associated with parental feeding style. Father's participation in the Supplemental Nutrition Assistance Program was associated with an increased likelihood of having an uninvolved feeding style (B=.90, OR=6.0, p=0.05). While participation in nutrition assistance or education programs was not directly associated with child weight, mothers' authoritarian feeding style and participation in SNAP (β=.44, p=0.03) was positively associated with children's BMI z‐score. These data suggest that the associations among food security status, parental feeding style, and participation in nutrition assistance programs are complex but potentially associated with childhood obesity risk.
Targeting of PMN Expressed Lewis‐X Blocks PMN Transepithelial Migration and Increases Phagocytosis and Surface Mobilization of Granule Contents
Authors: Brazil J , Sumagin R , Cummings R , Louis N , Parkos C
Published: June 2021

Dysregulated transepithelial migration (TEM) of neutrophils (PMN) is pathognomonic of numerous inflammatory disorders including inflammatory bowel disease (IBD), yet mechanisms controlling PMN TEM remain poorly defined. The glycan determinant Lewis X (Galβ1‐4 (Fucα1‐3) GlcNAc‐β‐R), expressed by PMN surface glycoproteins (including MAC‐1 and LFA‐1), has previously been implicated in adhesive interactions between PMN and endothelium. However, little is known about the wider role of Lex in PMN function following extravasation. Studies revealed that engagement of terminal Lex glycans (but not the related glycan sLex) increased PMN adhesive interactions, both with other PMNs and with intestinal epithelial cells, blocking PMN chemotaxis and TEM. Further, flow cytometry analyses revealed increased surface expression of Lex on human PMN following TEM. In addition to blocking PMN trafficking, targeting of Lex also altered post‐migratory PMN functions, increasing both PMN phagocytosis and the surface mobilization of azurophilic granule (CD63 and MPO) and specific granule (CD66b and lactoferrin) markers. Finally, immunohistochemistry analyses revealed robust expression of Lex by PMN in the crypt abscesses of individuals with active IBD. Therefore, Lex represents a potential target for regulating PMN trafficking into the intestinal lumen and PMN luminal function. Further, given its abundant expression on migrating PMN and during inflammation, Lex may be a rational target for modulating inflammation in IBD.
Extracellular Matrix Differentially Regulates Endothelial Nitric Oxide Synthase Production in HUVECs and Human Blood Outgrowth Endothelial Progenitor Cells
Authors: Yuan Yifan , Courtman David
Published: June 2021

Human outgrowth endothelial progenitor cells (BOECs), derived from peripheral blood mononuclear express endothelial protein profiles (i.e. CD31, 144, and vWF). Endothelial nitric oxide synthase (eNOS) is an important regulator of vascular tone and loss of eNOS activity is a hallmark of endothelial dysfunction. In this study, we examine the expression and activity of eNOS and elucidate the cause of differential regulation of eNOS in BOECs compared to mature endothelial cells. We found that BOECs express markedly lower eNOS protein (0.34 ± 0.13), mRNA (0.29 ± 0.17) as well as activity levels (0.49 ± 0.18) when compared to HUVECs or Human Aortic Endothelial Cells. When grown on fibronectin (FN), type I collagen (Col. I), and type IV collagen (Col. IV) we found significantly decreased eNOS protein, mRNA and mRNA stability in HUVECs compared to cells on polystyrene. The matrix mediated downregulation was blocked by β1 integrin siRNA and focal adhesion kinase siRNA transfection. In addition, rho‐associated protein kinase inhibitors including fasudil and Y27632 blocked the effect of ECM on eNOS downregulation in HUVECs. In contrast, in BOECs, eNOS protein expression was unchanged by cell‐ECM interactions. Interestingly, BOECs can highly deposit ECM molecules (Col. I, FN and Laminin) that assemble to an organized mesh‐like structure whereas HUVECs only express few ECM proteins which cannot form organized structures. Blocking Col. I synthesis with siRNA significantly enhanced eNOS expression in BOECs (1.77 ± 0.41 fold increase). Taken together, our results confirm a strong matrix mediated regulation of eNOS in endothelial cells and suggest that limited eNOS expression in BOECs results from higher ECM production.
Oxidized lipids in radiation therapy mediated acquired resistance of melanoma
Authors: Sahu Ravi , Travers Jeffrey
Published: June 2021

Our previous studies have established that pro‐oxidative stressors including UVB and chemotherapeutic agents generate oxidized lipids, glycerophosphocholines (Ox‐GPCs) that act as potent platelet‐activating factor‐receptor (PAF‐R) agonists and inhibit host anti‐tumor immunity. Since X‐ray radiation therapy (XRT) act as a potent pro‐oxidative stressor, the present studies investigated if XRT could thwart melanoma anti‐tumor immunity via PAF‐R activation. We demonstrate that treatment of in‐vitro melanoma and normal keratinocyte cells with XRT generates PAF‐R‐agonists only by melanoma cells in a dose and time dependent manner as measured by functional Ca2+ mobilization assay using retrovirally generated PAF‐R expressing and deficient epidermal cells. Antioxidants, vitamin C or N‐acetyl cysteine partially blocked IR mediated Ox‐GPCs production, indicating that XRT generates PAF‐R agonists via both enzymatic and non‐enzymatic pathways. Additionally, localized XRT of melanoma tumors grown on syngeneic mice resulted in PAF‐R agonists production. In a dual tumor model, we show that XRT of one tumor significantly augments the growth of other (untreated) tumor in a PAF‐R‐dependent manner. Moreover, XRT‐mediated PAF‐R‐dependent increased tumor growth was blocked by systemic cyclooxygenase‐2 (COX‐2) inhibitors. Furthermore, we detected several novel Ox‐GPCs with significantly increased PAF species in XRT‐treated melanoma cells compared to sham‐treated cells. These findings explain some instances of XRT treatment failure and provide novel therapeutic target by which PAF‐R agonists produced via XRT modulate tumor growth via PAF‐R‐COX‐2‐dependent pathway.
Stimulating the Resolution of Tumor Debris to Control Medulloblastoma
Authors: Barksdale Chantal , Sulciner Megan , Ramon Sesquile , Colas Romain , Bandopadhayay Pratiti , Huang Sui , Kieran Mark , Serhan Charles , Panigrahy Dipak
Published: June 2021

Background

Tumor recurrence occurs in one‐third of patients with medulloblastoma. Current clinical approaches to reduce medulloblastoma tumor burden, including chemotherapy, may contribute to relapse by creating tumor cell debris. The debris of dead cancer cells can act as a source of tumor stimulation via inflammation. A new direction has emerged in inflammation research with the discovery of endogenous specialized pro‐resolving lipid mediators. We hypothesize that resolvins and protectins represent a novel modality in medulloblastoma treatment by pharmacologically promoting the clearance of tumor debris.

Results

Flow cytometry confirmed that the chemotherapy cisplatin and the targeted therapy JQ‐1 generated medulloblastoma tumor cell debris. Chemotherapy‐ and targeted therapy‐induced tumor debris stimulated primary tumor growth. Protectins enhanced macrophage phagocytosis of medulloblastoma tumor debris and counter‐regulated secretion of pro‐inflammatory cytokines. Medulloblastoma tumor progression resulted in loss of resolvin levels. Resolvins inhibited medulloblastoma growth at nanogram levels without toxicity.

Conclusions

Our results demonstrate that enhancing endogenous clearance of tumor debris by resolvins and protectins represents a new biological target for medulloblastoma treatment.

Research Support: RO1 01CA170549
A Potential Role for Regulatory T Cells in Apoptotic Cell Clearance by Macrophages in a Murine Model of Acute Lung Injury
Authors: Proto Jonathan , Subramanian Manikandan , Islam Mohammed , Hook Jaime , Gusarova Galina , Bhattacharya Jahar , Tabas Ira
Published: June 2021

A key step in inflammation resolution is the clearance of apoptotic cells, or efferocytosis. Murine models of acute lung injury (ALI) have revealed that efficient efferocytosis is required for lung repair. If not resolved, ALI in humans progesses to acute respiratory distress syndrome, which affects 190,000 patients annually and has a mortality rate of 42%. It was recently reported that regulatory T cells (Tregs) induce neutrophil apoptosis in an LPS‐induced ALI model. Of note, Treg coordination of macrophage function has been established in numerous tissues, including the lung. We hypothesized that Tregs coordinate not only neutrophil apoptosis, but also their clearance by efferocytes like macrophages. To test this, we depleted Tregs in mice via IP injections of a CD25 antibody prior to intranasal LPS instillation. Immunostaining of lung sections was performed to identify apoptotic cell uptake by macrophages in situ. Strikingly, we found a significant decrease in efferocytosis in Treg‐depleted mice. To recapitulate these findings in vitro, we co‐cultured bone marrow‐derived macrophages (BMDM) with Tregs and then measured the uptake of apoptotic Jurkat cells following LPS stimulation. We found that LPS exposure led to a decrease in efferocytosis by control BMDMs, but not BMDMs co‐cultured with Tregs. These results indicate that Tregs may play a key role in efferocytosis. Future studies aim to elucidate Treg and macrophage communication both in vitro and in vivo. Findings from this work may reveal new strategies to prevent the progression of ALI to ARDS in human patients. This work was supported in part by a T32 training grant from the NIH (HL007343).
Staphylococcus aureus activation of NLRP3 inflammasome and necroptosis through MLKL exacerbates pneumonia
Authors: Kitur Kipyegon , Prince Alice
Published: June 2021

Staphylococcus aureus (SA) cause a highly inflammatory pneumonia associated with substantial pulmonary damage. We demonstrate that alveolar macrophages along with other immune effectors are depleted by SA toxin production that activates RIP1/RIP3/MLKL‐mediated necroptosis. SA infected Rip3‐/‐ mice and necrostatin‐1s‐treated mice retained significantly greater numbers of immune cells in the airways compared to control mice (p=0.0263 and p=0.0007 respectively). Rip3‐/‐macrophages had increased expression of the anti‐inflammatory markers CD206 (p=0.0104) and CD200R (p=0.0082) and decreased proinflammatory cytokine expression particularly Il‐1β production. These phenotypes were correlated with increased SA clearance and decreased pathology after SA infection. SA pore forming toxins were sufficient to activate necroptosis and NLRP3 inflammasome. MLKL blockade with necrosulfonamide decreased inflammasome activation and production of reactive oxygen species (ROS) induced by SA toxins. However, inhibition of ROS or inflammasome components did not protect immune cells from death. Our findings suggest that the activation of RIP1/RIP3/MLKL‐mediated necroptosis by SA modulates inflammasome activation and leads to loss of key airway immune cells contributing to the pathogenesis of SA pneumonia. Preventing the loss of these cells through necroptosis is a potential therapeutic target to block inflammatory airway damage during SA pneumonia.