bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced NO Bioavailability Hampers Exercise Induced Vasodilation in Familial Hypercholesterolemic Swine
Authors: de Beer Vincent J , Merkus Daphne , Bender Shawn B , Tharp Darla L , Ivey Jan R , Bowles Dougla K , Duncker Dirk J , Laughlin M Harold
Published: June 2021

Hypercholesterolemia impairs endothelial function (e.g. the NO‐cGMP‐ phosphodiesterase 5 (PDE5) pathway), limits shear stress induced vasodilation, and is thereby expected to reduce exercise induced vasodilation. To assess the actual effects of hypercholesterolemia on endothelial function and exercise induced vasodilation, we compared the effects of eNOS and PDE5 inhibition in chronically instrumented Yorkshire (Y) and Rapacz Familial Hypercholesterolemic (FH) swine, at rest and during exercise.

Exercise induced systemic vasodilation, i.e. the increase in systemic vascular conductance index (SVCi = SVC per Kg bodyweight), was markedly reduced in FH swine (27±5%) compared to Y swine (119±4%). As a result, during exercise mean arterial pressure remained constant in Y swine while it significantly increased in FH swine (from 91±6 to 110±8 mmHg). The vasoconstrictor effect of eNOS inhibition, with Nitro‐L‐Arginine, was attenuated in FH compared to Y swine, both at rest and during exercise. Furthermore, the vasodilator effect of PDE5 inhibition, with EMD360527, was also markedly reduced in FH compared to Y swine.

In conclusion, hypercholesterolemia hampers exercise‐induced vasodilation via reduced NO bioavailability. The reduced NO bioavailability results in a decreased activation of the NO‐cGMP pathway, as evidenced by a blunted vasodilator response to PDE5 inhibition.
Pregnancy induces cardiac hypertrophy with hypercontractile ventricular myocytes
Authors: Kennard Kaitlyn , Foster-Bey Lianna , Yanessa Deborah , Bailey Beth A
Published: June 2021

Pregnancy induces an increase in the physiological stress of the heart. The stress is primarily volume overload that results in increased cardiac output required to support the fetus(s). Persistent volume overload induced by pathological conditions result in cardiac function defects. The objective of the current study was to determine if volume overload during pregnancy disrupts cardiac myocyte contractile properties. Hearts from full term pregnant mice were removed, weighed and the aortas cannulated to isolate single ventricular myocytes via collagenase digestion. Rod shaped ventricular myocytes were placed in a chamber mounted on the stage of an inverted microscope and perfused with a physiological salt solution. Myocytes were electrically paced at 4Hz and shortening was measured with an IonOptix system. Hearts from pregnant mice (PM) were hypertrophied versus age and sex matched controls (CM) (239±7.3 vs 206±3.5 mg). Cardiac myocytes isolated from PM had significant increases in length (133±3 vs 119±2μ) and surface area (3380±177 vs 2844±78μ2) but no change in width. Contractions (% of resting sarcomere length) of myocytes from PM were increased (10.4±.7 vs 7.9±.7) versus CM as were the rates of shortening (3.92±.4 vs 3.08±.2 %RSL/sec) and relengthening (3.56±.3 vs 2.83±.25). Pregnancy induces physiological cardiac and myocyte hypertrophy accompanied by enhanced basal contractile performance.
The effects of play‐based physical activity on metabolic signatures in adolescents
Authors: Gulas Maria Eleni , Collier Scott
Published: June 2021

Exercise has been shown to decrease risk factors and aid in weight management, however little is known regarding the mechanisms influencing these shifts by the metabolic shift. The purpose of this study was to compare the effects of 4 and 8 weeks (4w, 8w respectively) of play based activity versus a typical 8 week (C) summer break activity on key metabolic signatures.

METHODS

Twenty‐two adolescent children were divided into 8 and 4 week activity and control groups (8w, 4w, C) respectively. Subjects reported to the Vascular Biology and Autonomic Studies Laboratory on two separate visits, at the beginning and the end of 4 or 8 weeks of the exercise program to give urinary samples at which time a graded exercise test was given (GXT) and descriptive characteristics were recorded. A gas chromatography time‐of‐flight mass spectrum analysis was performed on the samples and the results analyzed by special software.

RESULTS

A valid PLS‐DA model was obtained between post‐exercise subjects in 8 week group and control group. Significant changes were shown in pantothenic acid (fold change, FC 4.19), adenosine (FC 1.66), glyceric acid (FC 2.91), and creatinine (FC 1.61).

CONCLUSION

These data indicate that 8 weeks of play‐based physical activity can positively affect the metabolome of adolescents which may prevent the future development of obesity and CVD. Research was partially supported by a grant from the BeActive North Carolina Partnership (Collier, PI)
Voluntary exercise reduces cachexia and improves muscle function in mice carrying mammary gland tumors
Authors: IVARSSON NIKLAS , Rundqvist Helene , Östman Arne , Westerblad Håkan
Published: June 2021

Cachexia is a common feature in patients suffering from cancer. Here we use a PyMT knock in mice that develops spontaneous mammary gland tumors to study the effect of voluntary wheel running on skeletal muscle function. Mice were housed with the possibility to engage in voluntary exercise by a running wheel in the cage. Controls were housed with an immovable running wheel. Force at different frequencies and force during fatigue and recover was measured in isolated soleus (Slow twitch) and extensor digitorum longus (fast twitch).

In controls, soleus presented with clear atrophy in tumor carrying mice (6.7±0.5vs. 8.0±0.6 mg) and force at 100 Hz was reduced (51.4±5.6 vs. 88.8±16.5 kPa). Mice that exercised had a tendency for increased muscle mass (7.0±0.4 mg) and a compensated muscle force at 100Hz compared to voluntary run wild types (118.3±16.6kPa vs. 117.1±17.0kPa).

Western blot of whole muscle indicate that tumor mice had ~30% less PGC‐1α in both Soleus and EDL where a small increase could be seen in tumor carrying mice that had been running.

Conclusion

Skeletal muscles are afflicted by system wide influence from tumor growth. This effect can however to some extent be prevented by engaging in regular exercise.
Muscle contraction uncouples interactions between skeletal muscle ATGL and lipid droplet protein PLIN2
Authors: MacPherson Rebecca E.K. , Turnbull Patrick C. , Vandenboom Rene , Roy Brian D. , Peters Sandra J.
Published: June 2021

Skeletal muscle lipid droplet proteins (PLINs) are thought to regulate lipolysis through protein‐protein interactions on the lipid droplet surface. In adipocytes, PLIN1 regulates lipolysis by directly interacting with CGI‐58, an activator of adipose triglyceride lipase (ATGL). Upon lipolytic stimulation PLIN1 is phosphorylated releasing CGI‐58 to fully activate ATGL and initiate triglyceride breakdown. The absence of PLIN1 in skeletal muscle leads us to believe that this role is undertaken by another PLIN family protein. Our purpose was to examine interactions between PLIN2, ATGL and its co‐activator CGI‐58 at rest and following contraction. Isolated rat solei were incubated for 30 min at rest or during 30 min of intermittent tetanic stimulation (150 ms volleys at 60 Hz with a train rate of 20 tetani per min (25°C). Co‐precipitation revealed no detectable interaction between PLIN2 and CGI‐58 at rest or following stimulation. PLIN2 co‐precipitated with ATGL at rest, but significantly decreased by 30% following stimulation (p=0.013). Therefore, in skeletal muscle PLIN2 may regulate lipolysis through interacting with ATGL rather than CGI‐58.

Supported by NSERC, Canada.
Intrapulmonary Shunting is an Important Contributor to Exercise‐Induced Arterial Hypoxemia
Authors: Bates Melissa L. , Pegelow David F. , Farrell Emily T. , Baker Kim , Brodell Elizabeth , Eldridge Marlowe W.
Published: June 2021

Large diameter, intrapulmonary arteriovenous anastomoses (IPAV) are recruited by exercise in normoxia and hypoxia. We tested the hypothesis that IPAVs are important contributors to exercise‐induced arterial hypoxemia (EIAH) in both conditions by directly quantifying IPAV recruitment and gas exchange dysfunction. Human subjects (n=7) were studied while quietly breathing 21% or 10% O2 and at 85% of maximal exercise while breathing 21% or 10% O2. In each condition, we quantified the percentage of Tc99m‐labelled albumin microspheres traversing the pulmonary circulation and the alveolar‐arterial oxygen difference (A‐aDO2). Exercise increased microsphere passage in both normoxic (5/7 subjects, 2.5±3.5%) and hypoxic (4/7 subjects, 1.3±2.9%) exercise and in hypoxia alone (7/7subjects, 4.9±2.7%). Normoxic and hypoxic exercise increased the A‐aDO2 (7.6±13.4 and 17.7±5.2 mmHg, p<0.05) but not hypoxia alone. Microsphere passage was correlated with the A‐aDO2 in exercise (R2=0.61, p=0.001), suggesting that IPAVs contribute to EIAH by functioning as shunts. Interestingly, shunting through IPAVs was not observed in the absence of exercise (R2<0.01, p=0.93). We conclude that IPAVs are not true anatomic shunts, but function as diffusion‐limiting pathways when the cardiac output is elevated.
Ventilatory long‐term facilitation following acute intermittent or continuous hypoxaemia in awake humans: the role of carotid chemoreceptors and ventilatory drift to sustained hypercapnia
Authors: Griffin Harry Sebastian , Pugh Keith , Kumar Prem , Balanos George M
Published: June 2021

In awake humans, acute intermittent hypoxaemia (IH) causes a sustained increase in ventilation upon reoxygenation, known as ventilatory long‐term facilitation (vLTF), but only if combined with mild hypercapnia. It is not known if mild hypercapnia also unmasks vLTF following continuous hypoxia (CH). Carotid chemoreceptor (CC) sensitisation has been proposed as a mechanism for vLTF. We hypothesised that silencing the CC with 100% O2 would transiently abolish vLTF.

12 males undertook 3 trials. Mild hypercapnia was maintained in all trials and one minute exposures to 100% O2 occurred at baseline and recovery. Trials differed only in their hypoxic exposure; Trial 1‐Acute IH, Trial 2‐Acute CH, Trial 3‐Euoxia. Ventilation in Trial 1 and 2 increased from baseline to recovery (T1: 20.1 ± 1.1 vs. 25.1 ± 1.6, T2: 20.0 ± 1.2 vs. 25.1 ± 1.4 L/min).

Ventilation also increased in Trial 3 but to a lesser extent (19.8 ± 1.17 vs. 22.4 ± 1.84 L/min). Ventilation during 100% O2 increased from baseline to recovery in all trials (T1: 17.1 ± 1.2 vs. 21.8 ± 1.6, T2: 18.0 ± 1.5 vs. 22.5 ± 1.5, T3: 17.6 ± 1.4 vs. 20.2 ± 2.1).

In awake humans, during mild hypercapnia, CH induces a similar magnitude of vLTF as IH. However, a gradual positive drift in ventilation to mild hypercapnia accounts for ~50% of the vLTF. Silencing of the CC with 100% O2 exposure does not transiently abolish vLTF following acute IH or CH, suggesting CC sensitisation may not mediate vLTF.
Cystic fibrosis mice display different breathing patterns than non‐CF mice
Authors: Campanaro Cara K , Darrah Rebecca J , Dick Thomas E , Drumm Mitchell L , Jacono Frank J
Published: June 2021

Cystic fibrosis (CF) mouse models are used to understand disease physiology, but the CF mouse displays only mild pulmonary pathology. Changes in respiratory pattern are associated with health and disease, but ventilatory pattern has not been investigated in mouse models of CF.

Breathing patterns were recorded (200Hz) and quantified in CF mouse models (common mutation ΔF508 (n=22); CF mice complemented with human CFTR in the gastrointestinal tract (FABP‐CFTR, n=11); and wild type (WT, n=24)) using whole body plethysmography. If ANOVA p<0.05, then differences between groups were determined using a multiple comparisons procedure.

Respiratory rate was higher in ΔF508 as compared to WT mice (203 [187, 263 vs. 179 [164, 197] bpm; p<0.05). ΔF508 mice also exhibited greater coefficient of variation (CV) of respiratory cycle length (0.28±0.08 vs. 0.20±0.06; p<0.01). Similarly, the FABP mouse group had a respiratory rate (261 [216, 284] bpm) and CV (0.36±0.08) that were significantly greater than the WT group (p<0.05 for both).

CF mouse lines exhibited faster respiratory rates and greater ventilatory pattern variability than WT mice. Altered breathing patterns in FABP mice which do not succumb to intestinal obstruction suggest that these differences are not the result of the fragile state of the ΔF508 animals. CF mice may be a good model of pre‐clinical pulmonary disease in humans.
Overexpression of mir181a protects against Ang II induced osteopontin expression in VSMC
Authors: Remus Ebony Renee Washington , Lyle Alicia , Weber Martina , Searles Charles D , Taylor Robert
Published: June 2021

Angiotensin II (Ang II) promotes reactive oxygen species production, migration and ultimately hypertrophy in vascular smooth muscle cells (VSMCs). MicroRNAs (miRNAs) are critical regulators of protein expression in cardiovascular disease. However, the relationship between Ang II and miRNAs in VSMCs has yet to be determined. Osteopontin (OPN) is a multifunctional protein found in abundance in atherosclerotic plaques and in the injured arterial wall. In a mouse model of hypertension, we found that aortic OPN protein expression was increased 2‐fold after 7 days of 0.75mg/kg/day Ang II treatment in C57Bl/6 mice (p < 0.001). In vitro, we found Ang II increased OPN protein expression 4hrs after treatment by 420%±54 (p < 0.03) in cultured VSMCs. Literature searches revealed OPN mRNA as a potential target of mir181a. We found that Ang II decreased mir181a expression by 52%±7 (p < 0.0001) 24hrs post stimulation in VSMCs. We observed that over expression of mir181a inhibited Ang II induced increases in OPN protein expression at 4hrs in VSMCs by 69%±9 (p < 0.05). We conclude that Ang II decreases mir181a expression while increasing OPN protein expression, and that over expressing mir181a blocks Ang II induced OPN protein translation. These results suggest that mir181a may be a novel therapeutic approach to alter OPN protein expression during Ang II induced vascular dysfunction.
MicroRNA‐126 regulates cardiac angiogenesis induced by aerobic exercise training
Authors: da Silva Natan Daniel , Fernandes Tiago , Soci Ursula , Phillips Ian , Oliveira Edilamar
Published: June 2021

The purpose of this study is investigate the role of microRNA‐126 on cardiac angiogenesis induced by swimming training. Two groups of adult female Wistar rats (n=7/group) received either a sedentary (control), endurance training protocol 1 (T1), or training protocol 2 (T2). GroupT1: TF 60min/day swimming, 5x/week/10week with 5% overload, GroupT2: T1 to same protocol without the 8th week, 9th week trained 2x/day, 10th trained 3x/day. After the training period, hearts were harvested and total RNA isolated. MicroRNA‐126 gene expression analysis was performed by real‐time PCR. We assessed: markers of training, the cardiac capillary/fiber ratio, protein expression of VEGF, Spred‐1, Raf‐1/ERK1/2, PI3K/Akt/eNOS. The cardiac capillary/fiber ratio increased in Trained Groups. VEGF protein expression was increased 42% in T1 and 108 % in T2. Cardiac miRNA‐126 expression increased 26% (T1) and 42% (T2) compared with S. Spred‐1 protein level decreased 41% (T1) and 39% (T2), which consequently increase in angiogenic signaling pathway Raf‐1/ERK1/2. The gene expression of PI3KR2 was reduced 39% (T1) and 78% (T2), which consequently increase in angiogenic signaling pathway PI3K/Akt/eNOS. This study showed the involvement of miRNA‐126 in the regulation of exercise‐induced cardiac angiogenesis, by regulation of its targets that converged in an increase in the VEGF signaling and hence in angiogenic pathways.
Holocarboxylase synthetase (HLCS) interacts physically with nuclear corepressor (N‐CoR) and histone deacetylases (HDACs) to mediate gene repression
Authors: Liu Dandan , Zempleni Janos
Published: June 2021

Classically, HLCS is considered a protein biotinyl ligase. Evidence is emerging that HLCS also is a member of amultiprotein gene repression complex in human chromatin that mediates epigenetic synergies between biotinylation andmethylation events. Here we tested that HLCS also integratesgene expression by histone deacetylation, and that this effect is mediated by physical interactions among HLCS, N‐CoR, and HDACs. Physical interactions between HLCS and HDAC1 were confirmed by three independent procedures, namely co‐immunoprecipitation (co‐IP), limited proteolysis assays (LPA), and yeast two‐hybrid assays (Y2H). In addition, we developed a protocol to predict HLCS‐binding proteins in silico. Using this protocol, we predict that HLCS also interacts with N‐CoR. Studies of HLCS/N‐CoR interactions by co‐IP, LPA, and Y2H are currently in progress. We conclude that we discovered a novel epigenetic mechanism by which HLCS represses genes. Supported by ARD Hatch, and NIH DK063945, DK077816, and DK082476.
Although at rest, the rat esophagus is tensed anisotropically in situ
Authors: Lorber Mortimer
Published: June 2021

A cephalic organ, the rat lacrimal gland, is tensed in situ (Lorber, Adv Exp Med Biol 438:75–80, 1998), might a cervical one also be extended? After trachea removal under pentobarbital, 7 fasted male rats, wt 359 ± 10g (mean ± sd), had two dots placed axially in the mid‐esophagus about 5 mm apart to indicate length alterations. Width measurements were made at the level of the rostral dot. A calipers put in the jaws of a digital micrometer was used. For each dimension values were gotten at baseline, after removal of dorsal CT with small vessels, and after freeing by transections just beyond both dots. Overall statistical analysis was by the F test, and for paired values by the Tukey test. P ≤ 0.05 was deemed significant. Resting length between the dots was 4,80 ± 0.76 mm. After CT removal, 4.77 ± 0.78 mm. After transections to free the esophagus, 3.42 ± 0.97 mm. F≤0.001. This length was less than both baseline, P ≤0.01, and CT removal, P ≤0.001. Baseline width was 3.04 ± 0.39 mm. After CT removal, 3.09 ± 0.37 mm. After freeing, 3.28 ± 0.37 mm. F≤ 0.01. This width value exceeded both baseline, P ≤ 0.01, and CT removal, P 0.05, values. The esophagus shortens and widens as its attachments are removed. So, it is anisotropically tensed in situ. If it were not tensed the values would not have changed. The width change is likely secondary to the shortening, keeping its volume unchanged. Personal support.
Excitatory nerve stimulation and agonist stimulation induce gastric fundus smooth muscle contraction via stimulus dependent Ca2+ sensitization pathways‐not via myosin light chain phosphorylation
Authors: Bhetwal Bhupal P , Sanders Kenton M , Perrino Brian A
Published: June 2021

Ca2+ sensitization of smooth muscle contraction occurs by myosin light chain phosphatase (MLCP) inhibition. CPI‐17 phosphorylation or MYPT‐1 phosphorylation by Rho kinase (ROK) inhibits MLCP. Studies have shown that bath application of acetylcholine (Ach) induces Ca2+ sensitization in the gastrointestinal smooth muscles. We addressed a question; does excitatory nerve stimulation also cause Ca2+ sensitization in fundus smooth muscle? We stimulated fundus smooth muscle at a series of frequencies and determined the phosphorylated levels of MYPT‐1 at Thr 696 and 853 (pT696 and pT853), CPI‐17 (pT38) and LC‐20 at Ser 19 (pS19) by western blotting at different phases of contractions. Nerve stimulation robustly increased levels of pT38 but not pT696, pT853, and pS19. In contrast, bath application of Ach increased phosphorylation of pT696, pT853, and pT38, but not pS19. The L‐type Ca2+ channel blocker nicardipine completely blocked Ach induced contraction with a partial block in the increase of pT696 (but not pT853) and pT38 levels. The ROK inhibitor SAR1x partially blocked Ach induced contraction with a complete block of the increase in pT853 (but not pT696) and a partial block of the increase in pT38. At present, we conclude that excitatory nerve stimulation induces Ca2+ sensitization in gastric fundus smooth muscle by a different pathway than bath application of Ach. Supported by NIH grant RR018751 and DK40569.
Effect of pulses as part of a low glycemic index diet compared to a high fiber diet on HbA1c and blood lipids in type 2 diabetes
Authors: Kendall Cyril WC , Augustin Livia S , Mitchell Sandra , Sahye-Pudaruth Sandhya , Coveney Judy , Cerovic Aleksandra , Blanco Sonia , Jenkins David JA
Published: June 2021

Objective

Pulses including beans, lentils and chickpeas are low glycemic index (GI) foods however their effect on glycemic control and blood lipids diet has not been evaluated compared to a high fiber in type 2 diabetes.

Methods

121 subjects with type 2 diabetes were randomized to one of two 12‐week treatments: 1. Dietary advice included pulses (1 cup cooked/day) and other low GI starches and fruit; 2. Dietary advice to consume a high fiber whole grain diet (40g/2000kcal) (control diet). The primary outcomes were changes in HbA1c and blood lipids.

Results

Treatment differences in pulse intakes and dietary GI were significantly different (+169g and −12.5%, respectively, on Pulse‐low GI diet, p<0.0001). The Pulse‐low GI diet reduced HbA1c by 0.5% units (p<0.001 vs. high fiber), total cholesterol by 0.22 mmol/L (p<0.001), LDL by 0.09 mmol/L (p=0.063) and triglycerides by 0.045 mmol/L (p=0.064). Pulse intake was inversely correlated to changes in HbA1c (r=−0.24, p=0.014), total cholesterol (r=−0.27, p=0.004) and triglycerides (r=−0.24, p=0.012).

Conclusions

Dietary advice to consume pulses within a low GI diet improved both glycemic control and the serum lipid profile in type 2 diabetes.
Effects of Rice Consumption on Selected Indicators of Nutritional Status
Authors: Kennedy Eileen T. , Luo Hanqi
Published: June 2021

The Dietary Guidelines for Americans continue to recommend increased consumption of grains, particularly whole grains. The specific types of whole grains are rarely specified. The present study was aimed as evaluating whether rice consumption, both white and brown, had any association with nutrient intake, diet quality or body mass index. Data from the National Health and Nutrition Examination Survey (NHANES) 2007–2008, combined with the Food Commodity Intake Database (FCID), were used. Study participants were categorized into three levels: high rice consumers, medium rice consumers, and zero rice consumers. Rice consumers had a significantly higher intake of calcium, thiamin and folate but not other nutrients. Rice consumers, both medium and high, were more likely to have a body mass index less than 25.0 (p<0.05), despite the fact that the high rice consuming group had significantly higher energy intakes. Diet quality as measured by the USDA Healthy Eating Index was higher for rice consumers. These results suggest that the type of grain, as well as amount of grain, consumed may be an important influence on nutritional status.
Nutrient intakes and weight status of adult Canadian breakfast consumers versus non‐consumers, and of those consuming breakfasts with versus without ready‐to‐eat cereal
Authors: Barr Susan I. , DiFrancesco Loretta , Fulgoni Victor L.
Published: June 2021

Higher nutrient intakes are reported in breakfast consumers vs. non‐consumers, and in those who include ready‐to‐eat cereal (RTEC) at breakfast vs. those who do not. We examined these differences using Day 1 data from adult participants (age ≥19; n = 20,157) in the Canadian Community Health Survey Cycle 2.2 (2004), a nationally‐representative sample. Overall, 90% of Canadian adults reported eating breakfast, increasing from 82% (age 19–30) to 97% (age 71+). Breakfast consumers had higher (P ≤ 0.01) energy intakes than non‐consumers (mean ± SE: 2112 ± 15 vs. 1933 ± 34 kcal/d), but body mass index (BMI; from measured height and weight) and weight status (odds ratio for overweight/obesity) did not differ. They also had higher energy‐adjusted intakes of protein, carbohydrate (CHO), fibre, cholesterol, calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe), potassium (K), and vitamins A, B1, B2, B3, B6, folate, C and D. Among breakfast consumers, 23% included RTEC. Energy intakes and weight status of RTEC consumers and non‐consumers did not differ, but RTEC consumers had higher intakes of CHO, fibre, Ca, P, Mg, Fe, K, zinc, vitamins B1, B2, B6, folic acid and D, and lower cholesterol and fat intakes. Breakfast made a positive contribution to adult Canadians’ nutrient intakes, and those who ate RTEC breakfasts had a more favourable nutrient profile than those who ate other breakfasts. (Supported by Kellogg Canada Inc.)
Establishment of vitamin A requirement for Chinese children
Authors: Zeng Jing , Yao Ping , Xu Jian , Hao Liping , Li Zhaolin , Tang Guangwen , Cao Wenhong , Sun Xiufa , Yang Xuefeng
Published: June 2021

Adequate intake (AI) of vitamin A has not been established for Chinese children. To establish AI of vitamin A for Chinese children, we evaluated dietary intake in well‐nourished children, whose liver vitamin A levels were ≥0.07μmol/g and <1.05μmol/g as determined by 3‐day and 18‐day deuterated‐retinol‐dilution (DRD) techniques. We found that the intake of dietary vitamin A and β‐carotene were significantly correlated with vitamin A stores in the body, but not with the serum concentration of retinol. The mean (±SD) vitamin A intake was 476.9±196.7 μg retinol equivalence (RE)/day for the 4~6 y and 529.1±87.2μg RE/d for the 7~9 y children. The total body stores of vitamin A derived from 3‐day DRD before the equilibrium of vitamin A was reached were similar to those derived from 18‐day DRD, when the vitamin A equilibrium was reached. Based on our results, we estimate the average dietary vitamin A intake in children with an appropriate vitamin A reserve as their adequate intake, that is, around 450 RE μg/d (95%CI 384~569 RE μg/d) for 4~6 y and 550 RE μg/d (95%CI 500~559 RE μg/d) for 7~9 y children.
Plasma vitamin D is associated with insulin sensitivity in youth with Type 1 Diabetes
Authors: The Natalie , Crandell Jamie L , Norris Jill M , Davis Elizabeth J Mayer-
Published: June 2021

The identification of modifiable risk factors associated with insulin sensitivity (IS) is critical for improving health outcomes in persons with type 1 diabetes (T1D). Little is known about the association between vitamin D and IS in this population. We examined the prevalence of plasma vitamin D [25(OH)D] deficiency (<50 nmol/L) and its association with IS using data from the SEARCH for Diabetes in Youth Study (n=1,127). Participants had physician‐diagnosed T1D and diabetes autoantibody positive at enrollment (diabetes duration mean=10.0 mo) with data at baseline and 12 months later. IS was estimated using a validated equation. Of these participants, 47% had 25(OH)D deficiency with variation by race and age (p<0.05). IS was lower in those who had deficient (mean IS=10.2) vs. sufficient (≥75.0 nmol/L) levels of 25(OH)D (mean IS=11.5; p<0.01). Mixed effects models were used to determine the association between 25(OH)D and IS, adjusting for diabetes duration, age, race/ethnicity, gender, insulin regimen, HLA genotype, clinic site, season at time of visit, fasting C‐peptide (FCP), and FCP*diabetes duration. 25(OH)D was positively associated with IS (β=0.008, p=0.001). Further adjustment for BMI z‐score yielded a similar result (β=0.005, p=0.004). Findings highlight the need to increase vitamin D and further examine the role of vitamin D on IS in youth with T1D. Funding: NIH/NIDDK R01 DK077949
Dietary protein and risk of elevated blood pressure in adolescent girls
Authors: Buendia Justin G , Hasnain Syed R , Singer Martha R , Moore Lynn L
Published: June 2021

The prevalence of elevated blood pressure (EBP) has risen steadily for U.S. adults and children during the past 20 years. The goal of this study is to estimate the effect of dietary protein on adolescent blood pressure. Ten years of follow‐up data from 2379 girls in the National Growth and Health Study ages 9–10 years at baseline were used. Eight sets of 3‐day diet records were collected during the study. BP was measured 3–4 times at each annual visit. Outcomes of interest to these analyses include mean SBP, DBP and risk of EBP in late adolescence (mean age=18.3 years). Analysis of covariance and multiple logistic regression models were used to control for potential confounding by age, race, SES, height, physical activity, age at menarche, and TV/video viewing time. Adjusted mean SBP and DBP levels declined linearly with increasing quintiles of protein intake (SBP: 111.8, 109.7, 108.5, 107.7, 107.4 mmHg; DBP: 67.2, 65.8, 65.3, 64.5, 64.6 mmHg, respectively, for quintiles 1–5; p‐trend<0.0001 for both). Girls in the lowest quintile of intake (<1.0 g•kg body weight−1•day−1) vs. the highest quintile (>1.7 g•kg body weight−1•day−1) were 3.3 times as likely to develop EBP in late adolescence (95% CI: 2.1–5.0). These results were largely attenuated by inclusion of BMI in the models. Dietary protein intake above the current RDA had strong beneficial effects on adolescent BP resulting from its intermediate effects on body composition.

Grant Funding Source: NIDDK and Small Grants
Decreased Response of Influenza Specific CD8+ T Cells From Overweight and Obese Humans
Authors: Paich Heather , Sheridan Patricia , Beck Melinda
Published: June 2021

During infection with influenza virus, CD8+ cytotoxic T cells are essential for limiting the severity and spread of virus by killing infected cells. Because obesity is a risk factor for increased mortality from pH1N1 infection, we hypothesized that a decreased CD8+ T cell number and/or activity may have contributed to the increased susceptibility. Peripheral blood mononuclear cells (PBMCs) from healthy weight, overweight, and obese subjects post vaccination with 2009–2010 seasonal vaccine were stimulated ex vivo with influenza A/Brisbane/59/2007, a component of the vaccine. PBMCs were stained with fluorochrome‐conjugated antibodies and analyzed with flow cytometry. PBMCs from obese subjects exhibited a lower percent increase in CD8+ cytotoxic T cells expressing the early activation marker CD69, than from healthy weight participants. Furthermore, PBMCs from obese participants showed a lower percent increase in activated CD8+ T cells expressing granzyme B and PBMCs from obese and overweight participants showed a lower percent increase in CD8+ T cells expressing IFNγ, in comparison to PBMCs from healthy weight participants. Dendritic cells are required to activate CD8+ T cells, however there were no differences in total and activated dendritic cell numbers between groups. These data suggest that obese and overweight individuals would have greater difficulty recovering from influenza virus infection.

Grant Funding Source: NIH RO1AI078090 and P30DK056350
A three‐part mixed‐effects model to estimate usual total nutrient distributions from food and dietary supplements
Authors: Dodd Kevin Wayne , Verkaik-Kloosterman Janneke , Dekkers Arnold , vant Veer Pieter , Ocke Marga
Published: June 2021

When estimating distributions of usual nutrient intake (as part of monitoring the nutritional status of a population), it is vital to consider intake from all sources, including dietary supplements (DS). Estimation based on short‐term measurements is hampered by within‐person variation in consumption and skewed/multimodal distributions of observed intake. Summing measured intakes from food sources and from DS prior to correction for within‐person variation (“add‐then‐shrink”) may produce biased estimates of usual total intake. We present a 3‐part model using a “shrink‐then‐add” approach to estimate usual intake separately 1) from food, 2) from DS among DS users, and 3) from food among DS nonusers, accounting for several other covariates. The population distribution of usual total intake is estimated by combining these 3 distributions, allowing possible interdependence. The new model extends the approach developed by the US National Cancer Institute, and is designed to eliminate some potential biases of the “add‐then‐shrink” approach. Usual total vitamin D intake for children was estimated via the 3‐part model and data from the Dutch food consumption survey (n = 1279). This methodology may also apply in other cases, e.g., where high concentrations of nutrients appear in episodically consumed foods.
Development of a method for estimating long‐term intake of foods and nutrients
Authors: Barraj Leila M , Murphy Mary , Scrafford Carolyn , Bi Xiaoyu , DiNovi Michael
Published: June 2021

Statistical models have been proposed to derive estimates of usual intake of foods and nutrients from short term consumption data, such as the data collected by the 24‐hour dietary recall component of the National Health and Nutrition Examination Survey (NHANES) (Nusser et al 1996, Tooze et al 2006). We have developed an alternative model that combines frequency of consumption data from 14‐day diaries collected by The NPD Group (NPD) as part of the National Eating Trends (NET) survey with gram per eating occasion (eo) data from NHANES. The model was restricted to NET participants reporting 10+ diary days. There were proportionately more young children (2–6 y) and older adults (50+ y) in the NET database. NET survey participants reported on average one less line item per day as compared to those in NHANES. There was no evidence of respondent's fatigue in the NET (average number of lime items reported per day in weeks 1 and 2 was 13.5 and 13.7). We mapped each food reported in NET to one or more foods reported in NHANES. We derived distributions of g/eo for all mapped NHANES foods and the model assigned each NET eo a g/eo from the generated distributions. We present results of our comparison of the 2 surveys, and the assumptions and approach used to develop the model and combine the data from the 2 surveys. Supported by the US Food and Drug Administration.
Comparison of cooperation between image capture and digital recording of evening meals among adults
Authors: Schap TusaRebecca E , Franks Melissa M , Boushey Carol J
Published: June 2021

Two broad categories of mobile applications for monitoring dietary intake are image‐capture and digital versions of traditional recording methods. A study examining marital interactions among 21 spouse pairs (n = 42, aged 47–82 y) allowed for a comparison of cooperation between capturing an image of the evening meal and digitally recording the foods and amounts of those same meals at the end of the day. Participants were provided a digital camera to take an image of their evening meals for 7 days. A fiducial marker was provided to include in each image. An HTC mobile telephone was provided for recalling and recording the same evening meals. Based on the images, meals were consumed at home and at a variety of restaurants. There were significantly more images captured than digital entries (mean difference 1.67, p <0.000). Whereas all participants provided at least 3 images of eating events, 8 participants did not complete any digital entries. Over 50% of the participants completed 7 digital entries (n=22, 52%). Over 75% of the participants captured images for each of the 7 days (n=32, 76%), and 97% of these images included the fiducial marker. These results reinforce the ease of taking images of meals over digital recording even among older adults. The possibility exists that couples may support one another with tasks related to monitoring dietary intakes, which would be a phenomena to exploit to enhance image capture.

Grant Funding Source : National Cancer Institute (1U01CA130784‐01) and the National Institute of Diabetes, Digestive, and Kidney Disorders (1R01‐DK073711‐01A1). TusaRebecca Schap is a recipient of the Indiana CTSI Career Development Award (TL1 RR025759‐03; A. Shekhar, PI).
Insights into Anti Cancer Agent‐Induced Cardiotoxicity
Authors: Weerasinghe Priya , Brown Robert , Buja L. Maximilian
Published: June 2021

Anti cancer therapy is often complicated by the development of toxicity to the heart. Cardiotoxicity due to anti neoplastic therapy is important to recognize and address as this may have a significant impact on the overall prognosis and survival of those patients. Recent studies have explored the relationship of cardiomyocyte cell injury to the major modes of cell death, and it appears that cardiomyocyte cell injury involves the pathways of apoptosis and oncosis. We have found sanguinarine, a known anticancer agent, to induce apoptosis and oncosis in several malignant cell lines when treated with concentrations of 1.5 μg/ml and 25 μg/ml, respectively. Furthermore, a similar biphasic pattern of cell death was observed when cultured primary cardiomyocytes were treated with the same sanguinarine concentrations. Using this primary cardiomyocyte cell model we proceeded to study the molecular expression profile of oncosis. Microarray analysis of 4 repeated experiments revealed altered expression of 2514 probes in sanguinarine‐induced oncosis (p value <0.001). The pathways involved include mitochondrial dysfunction, fatty acid metabolism, p53 signaling and oxidative phosphorylation. The discovery of novel oncosis‐related molecules could facilitate the development of more effective therapeutics to combat and prevent chemotherapeutic cardiotoxicity.
Learning from Insect Brains: CNS Processing of Behaviorally Significant Odors
Authors: Hildebrand John G.
Published: June 2021

We seek to understand neurobiological mechanisms through which information about behaviorally significant olfactory stimuli is encoded, processed, and integrated with inputs of other modalities in the CNS and specifically how olfactory information controls natural behavioral responses. We study the antennal lobes (ALs), the primary olfactory centers in the brain of the giant sphinx moth Manduca sexta. As in olfactory bulbs of vertebrates, the ALs are characterized by glomeruli – condensed‐neuropil structures in which primary‐sensory and central neural elements interact synaptically. Insights from our prior work on the moth's sex‐pheromonal communication system led to recent analysis of olfaction‐dependent interactions with host plants. A multidisciplinary approach combining chemical characterization of natural volatiles, behavioral experiments in a laboratory wind tunnel, and electrophysiology has enabled us to determine how mixtures of volatiles, at natural concentrations, control source‐seeking behavior and are encoded in the ALs. Mounting evidence points to coincident firing of glomerular output neurons as a mechanism for neural coding of the context or significance of a behaviorally ‘meaningful’ odor. (This research has been supported by NIH grant R01 DC002751.)
Bone marrow‐derived multipotent adult progenitor cells are capable of functional sinus node myocytes differentiation
Authors: Zhang Chuansen , Zhang Xi , Liu Yanchun
Published: June 2021

Although recent studies of biological pacemaker are focused on overexpression of bioengineered ion channels and genetically modified stem cells. However, short‐term expression of gene and unkown bio‐safety limit the application of current biological pacemakers. A logical approach to recreate an ideal cellular microenvironment in Petri dishes is to hand the task over to differentiated cells. The aim of the present study is to investigate if multipotent adult progenitor cells(MAPCs) can be induced into pacemaker‐like cells by co‐culture assays. After 1 week co‐culture with neonatal sinus node myocytes, MAPCs from bone marrow of rat expressed HCN2 and HCN4 mRNA and proteins until 4 week. HCN4 mRNA was more abundant than HCN2. The Kir2.1 and Kir2.2 that are responsible for inward‐rectifier K+ channels were decreased with culture time. The co‐cultured MAPCs showed sinus node myocytes‐like action potentials and drived quiescence cardiomyocytes to beat. These results suggest that MAPCs could differentiate towards functional sinus node myocytes when co‐cultured with neonatal sinus node myocytes.
A conserved RNA structure regulates polyamine‐dependent alternative splicing and NMD
Authors: Ares Manuel
Published: June 2021

Post‐transcriptional gene regulation in vertebrates can be mediated through coupling of alternative splicing to nonsense‐mediated decay (AS‐NMD), by controlling inclusion of stop codon‐containing exons (SCEs). Despite the absence of protein‐coding information, many SCEs are highly conserved, suggesting the presence of regulatory elements. We have identified a complex RNA structure spanning an SCE in a gene encoding a key enzyme in polyamine metabolism. In high levels of spermine or nonmetabolizable spermine analogs, the exon is skipped, increasing the levels of functional Spermine/Spermidine Acetyl Transferase (SSAT) mRNA. Depletion of spermine causes exon inclusion and decay of SSAT transcripts. We have shown that this structure is necessary and sufficient for the spermine‐regulated splicing. Detailed structure probing of a model RNA folded in the presence or absence of spermine shows that exon structure is profoundly influenced by spermine, but not spermidine, putrescene, ethylene diamine, or ammonium ion. The concentration of spermine required to change folding in vitro is between 10 and 50 uM, whereas intracellular concentrations of spermine are in the millimolar range. Once folded, the RNA structure is resistant to changes in spermine level. We suggest that splicing regulation of this SCE is mediated by the concentration of spermine (or another large polyamine in the cell), and that the exon senses this level directly. Control of alternative splicing by RNA structures for protein coding exons is rare in vertebrate genomes, however it may be more common in AS‐NMD, where the sequences of stop codon exons are free to evolve. Supported by NIH Grant GM040478.
Alternative Replisome Assembly is Directed by RecA to Bypass Obstacles
Authors: ODonnell Mike Edward , Georgescu Roxana , Yao Nina Y. , Langston Lance , Isabel Kurth , Indiani Chiara
Published: June 2021

Chromosomal replicases utilize circular sliding clamps for high‐processivity during replication. Sliding clamps not only bind the chromosomal replicase, but they also function with all 5 DNA polymerases in E. coli as well as other proteins for repair and lesion bypass. This presentation focuses on the use of the sliding clamp by a variety of DNA polymerases in crossing barriers that are encountered during replication. We find that the replicase, Pol III, acting in the context of a replisome including helicase, primase and the sliding clamp at a replication fork, can rapidly exchange with other DNA polymerases, such as translesion enzymes, that can allow the replisome to bypass lesions that it encounters during replication. We demonstrate that RecA, the recombinase, dictates the polymerase occupancy at the replication fork. To perform this function, RecA must be in the nucleofilament form, RecA*, which should only be present during DNA damage; it acts in trans. RecA* inhibits the Pol III chromosomal replicase, while greatly promoting translesion polymerases (TLS Pols), Pols II and IV. Interestingly, the polymerase that occupies the replisome dictates the speed of the helicase. We also find that RecA* converts TLS Pol V to a strand displacement enzyme, an activity needed for recombinational strand exchange. Finally, we present single‐molecule studies that examine the function of the third polymerase within the replisome.
Dissecting the BCL‐2 family interaction network with stapled peptides: mechanistic insights and pharmacologic opportunities
Authors: Walensky Loren David
Published: June 2021

The BCL‐2 family of apoptotic proteins regulates the critical balance between cellular life and death. Because so many medical conditions can be categorized as diseases of either too many or too few cells, elucidating the structure and function of BCL‐2 members and developing pharmacologic strategies to target them have become high priority scientific objectives. When overexpressed in cancer, anti‐apoptotic BCL‐2 family proteins such as BCL‐2 and MCL‐1 neutralize the pro‐apoptotic stimuli delivered by modern treatments, enforcing cancer cell survival. The pro‐apoptotic executioner proteins, BAX and BAK, are retained in most cancer cells but remain shackled by their anti‐apoptotic counterparts. Drugs to control the “on” and “off” switches of BCL‐2 family proteins would provide a new generation of treatments to modulate the rheostat that controls cellular life and death. BCL‐2 family members interact with one another via a conserved alpha‐helical domain that we have chemically recapitulated in the form of Stabilized Alpha‐Helices of BCL‐2 domains or SAHBs. These “stapled” peptide helices demonstrate alpha‐helical structure, protease resistance, cellular uptake, and the capacity to engage their intracellular protein targets with high affinity and specificity. We have applied SAHBs to elucidate the binding specificities of BCL‐2 proteins, uncover novel sites of functional interaction, dissect mechanism of apoptotic activation, and advance a new series of prototype therapeutics for modulating apoptosis in diseases of pathologic cell survival.

This research was supported by NIH grants R01CA050239 and P01CA92625 to L.D.W.
A novel inducible mutagenesis system in Mycobacterium tuberculosis
Authors: Mizrahi Valerie , Warner Digby , Ndwandwe Duduzile , Abrahams Garth , Venclovas Ceslovas
Published: June 2021

In Mycobacterium tuberculosis (Mtb), damage‐induced mutagenesis is dependent on the C‐family DNA polymerase, DnaE2. Included with dnaE2 in the Mtb SOS regulon is an operon comprising Rv3395c, which encodes a protein of unknown function, and Rv3394c, which is predicted to encode a Y‐family DNA polymerase. Our results show that Rv3395c (designated imuA′) and Rv3394c (imuB) are individually essential for induced mutagenesis and damage tolerance and that ImuB interacts with both ImuA′ and DnaE2, as well as with the β‐clamp. Disruption of the ImuB‐β clamp interaction significantly reduces induced mutagenesis and damage tolerance, phenocopying deletion mutants in imuA′, imuB, and dnaE2. Despite retaining structural features characteristic of Y‐family members, ImuB homologs are pseudo‐polymerases which lack conserved active‐site residues. In contrast, mutation of catalytic, aspartate residues in DnaE2 reproduces the dnaE2 gene deletion phenotype, implicating this polymerase in mutagenic lesion bypass. Together, these results identify the split imuA′‐imuB/dnaE2 cassette as a compelling target for compounds designed to limit mutagenesis in a pathogen increasingly associated with drug resistance
Persistent Food Insecurity is Associated with Higher Levels of Cost‐Related Medication Non Adherence in Low‐Income Older Georgians
Authors: Sattler Elisabeth Lilian Pia , Lee Jung Sun
Published: June 2021

The purpose of this study was to examine the relationship between changes in food insecurity (FI) and cost‐related medication non‐adherence (CRN) among Older Americans Act Nutrition Program participants and waitlisted people in Georgia. This study used 3 waves of self‐administered mail surveys, conducted 4 months apart between 2008 and 2009 (n = 664, mean age 74.6 ± 8.9, 71.5% women, 31.0% African American). FI was assessed by using a modified version of the nationally validated standard 6‐item US Household Food Security Survey Module. Practice of 5 CRN behaviors (i.e., splitting pills, delaying refills, and skipping doses) was evaluated. Changes in FI and CRN were determined based on ≥ 2 repeated measures. Over the 8‐month period, 35.8% were persistently food insecure, 12.7% became food insecure, 16.7% became food secure, and 34.8% were persistently food secure; 29.2% persistently practiced CRN, 16.7% started practicing CRN, 15.7% stopped practicing CRN, and 38.4% were persistently medication adherent. Participants with persistent FI and CRN were more likely to be younger, low‐income, and in poorer health. After controlling for potential confounders, persistently food insecure and newly food insecure individuals were 8.2 times (95% CI: 5.4, 12.5) and 5.3 times (95% CI: 3.2, 8.8) more likely to report higher levels of CRN than persistently food secure individuals. This study was funded in part by UGA FACS.