bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowledge, belief and attitude of low‐income postpartum women about anemia and iron supplementation
Authors: Mitra Amal K , Khoury Amal J
Published: June 2021

Prevalence of anemia after childbirth is high in low‐income women. As part of treatment of anemia in low‐income women after delivery, we assessed women's knowledge, beliefs and attitudes about anemia, sources of iron, and effect of iron deficiency. Using a cluster sampling design, 959 women were assigned to one of the three treatment strategies: 1) Controls, who were offered the conventional selective anemia screening among high‐risk women after delivery; 2) Group I (Universal anemia screening): All low‐income women were screened for anemia, and anemic women were given iron tablets; 3) Group II (Universal supplementation): All women in this group received a 60 mg iron tablet daily for 2 months, irrespective of their hemoglobin status. Nearly 45% women knew that anemia is common in women after delivery. More than 55% women mentioned that vitamin C helps in iron absorption, whereas 72% were wrong saying that foods lose iron when cooked in large amounts of water. Their knowledge about sources of iron was mixed. They correctly mentioned dried beans (75%) and green vegetables such as broccoli, peas and spinach (85%) as good source of iron. However, only 25% mentioned it correctly that chicken meat is a good source of iron. Majority of the women knew that low iron increases chance of infection (76%), makes people tired (83%), and decreases their memory (83%). They also believed that low iron does not help them deliver a healthy baby (84%). Nearly 78% of women expressed that all pregnant women should take iron supplements.

The study was supported by the Centers for Disease Control and Prevention (CDC‐NCCDPHP‐TS‐0780).
Chronic Developmental Iron Deficiency Decreases Hippocampal Neurogenesis and Leads to Depressive‐like Behavior in Rats
Authors: Oh Sugyoung , Yi Jee Hyun , Chung Jayong
Published: June 2021

Severe iron deficiency in early life leads to various behavioral problems in humans as well as in animal models. Down‐regulation of neurogenesis in the hippocampus has been associated with depression. In the present study, we examined whether the developmental iron deficiency alters the neurogenesis of the hippocampus in rat and affects behavior. Pregnant rats were fed an iron‐sufficient (36ppm Fe, IS) or iron‐deficient (<6ppm Fe, ID) from gestation day 2 until weaning on postnatal day 21. At weaning, pups were continued to be fed the same diet as their respective maternal diet for additional four weeks. Neuronal cell proliferations in the hippocampus were determined by BrdU labeling. Anxiety‐ and depressive‐like behaviors were assessed using an elevated plus maze (EPM) test and forced swimming test (FST), respectively. ID rats had significantly lower levels of blood hemoglobin concentrations than those of IS rats. ID rats had significantly decreased numbers of BrdU‐positive cells in the dentate gyrus layer of the hippocampus as compared to IS rats. Moreover, ID rats showed fewer entries and less time spent in open arms in the EPM test and exhibited significantly increased immobility time in the FST. Our study data suggest that severe iron deficiency from the developmental period affects behavior in adult rats, which may be associated with the down‐regulation of neurogenesis in the hippocampus region of rat brain.
Effect of lycopene supplementation on lung carcinogenesis induced by tobacco carcinogen 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK) in ferrets
Authors: Aizawa Koichi , Veeramachaneni Sudipta , Liu Chun , Smith Donald , Ausman Lynne M , Wang Xiang‐Dong
Published: June 2021

A protective role of lycopene (LYC) against smoke‐induced squamous metaplasia has been previously reported in a ferret model. In this study, we examined the induction of lung cancer in ferrets initiated with the NNK and investigated the effects of supplementing LYC on lung carcinogenesis. Ferrets (6 groups, n=8–10/group) were injected with NNK (50 mg/kg BW, i.p. once a month for 4 consecutive months) or saline as control with or without two doses of LYC supplementation (2.2 or 6.6 mg kg BW/day), for 26weeks. The results showed that the NNK exposure alone induced both preneoplastic lesions and lung tumors that are pathologically similar to humans. Although the LYC supplementation did not significantly inhibit the incidences of lung tumors, the LYC supplementation was associated with a low mortality rate compared to ferrets treated with NNK alone. Interestingly, the NNK treatment was associated with induction of liver cancer, which was ameliorated by LYC supplementation. Both hepatic and plasma LYC were detected by HPLC in the LYC supplemented groups. In summary, the development of both preneoplastic and neoplastic lesions in ferret lungs by injecting NNK alone provides an excellent model for studying lung carcinogenesis. Although the effects of LYC against lung tumors are inconclusive, the LYC supplementation was associated with both lower NNK induced mortality and hepatic damage in this model.
Interleukin‐6 induced matrix metalloproteinase‐9 expression in macrophages: Cyclooxygenase‐2‐dependent and independent pathways
Authors: Kothari Poonam , Pestana Roberto , Mesraroua Rim , Elchaki Rim , Falcone Domenick J.
Published: June 2021

Elevated plasma IL‐6 levels are associated with an increased risk for coronary heart disease; however, causality remains undefined. We previously reported that COX‐2‐dependent PGE2 synthesis and binding to EP4 stimulates macrophage MMP‐9 expression, which has been implicated in the pathogenesis of vascular diseases. In the present studies, we determined whether IL‐6 regulates the COX‐2→PGE2→EP4 receptor axis in macrophages. Results demonstrate that IL‐6 inhibited macrophage expression of 15‐PDGH, and stimulated expression of COX‐2 and mPGES‐1, resulting in an increase in PGE2 levels. Likewise, IL‐6‐induced MMP‐9 expression in macrophages. Whereas, the COX‐2 inhibitor celecoxib completely blocked IL‐6 induced PGE2 synthesis, MMP‐9 expression was partially attenuated. These data reveal COX‐2‐ dependent and independent mechanisms through which IL‐6 stimulates MMP‐9 expression. Engagement of the IL‐6 receptor triggers activation of the JAK/STAT and MAPK pathways leading to the expression of target genes. Pre‐incubation of macrophages with the JAK inhibitor tofacitinib blocked expression of several IL‐6‐induced genes, but paradoxically stimulated MMP‐9 expression. In contrast, MMP‐9 expression was completely blocked by the MEK inhibitor U0126. Thus, inhibition of MAPK emerges as a major strategy to block IL‐6‐induced MMP‐9 expression in macrophages. These studies were supported by HL093331.
Activation of plasma kallikrein‐kinin system mediates synovial recruitment of endothelial progenitor cells in arthritis
Authors: Dai Jihong , Yang Aizhen , Colman Robert W , Wu Yi
Published: June 2021

OBJECTIVE

This study aimed at determining whether activation of the plasma kallikrein‐kinin system (KKS) mediates synovial recruitment of endothelial progenitor cells (EPCs) in arthritis.

METHODS

EPCs were isolated from Lewis rat bone marrow, and expression of progenitor cell‐lineage markers and functional properties were characterized. EPCs were injected intravenously into Lewis rats with arthritis, and their recruitment and formation of de novo blood vessels in inflamed synovium were evaluated. The role of plasma KKS was examined using plasma kallikrein inhibitors. A transendothelial migration assay was used to determine the role of bradykinin and its receptor in EPC mobilization.

RESULTS

EPCs from Lewis rats exhibited a strong capacity to form tubes and vacuoles and expressed increased levels of bradykinin type 2 receptor (B2R) and progenitor cell markers CD34 and Sca‐1. In Lewis rats with arthritis, EPCs were recruited into inflamed synovium at the acute phase of disease and formed de novo blood vessels. Inhibition of plasma kallikrein significantly suppressed synovial recruitment of EPCs and hyperproliferation of synovial cells. Bradykinin stimulated transendothelial migration of EPCs in a concentration‐dependent manner. This was mediated by B2R, as demonstrated by the finding that knockdown of B2R with silencing RNA completely blocked bradykinin‐stimulated transendothelial migration. Moreover, bradykinin selectively up‐regulated expression of the homing receptor CXCR4 in EPCs.

CONCLUSION

These observations demonstrate a novel role of plasma KKS activation in the synovial recruitment of EPCs in arthritis, acting via kallikrein activation and B2R‐dependent mechanisms. B2R might be involved in the mobilization of EPCs via up‐regulation of CXCR4.
Cellular and molecular response of mouse subcutaneous tissue to a triantibiotic intracanal medication
Authors: Faria Gisele , Pereira Maristela S.S. , Cardoso Cristina R. , Silva João S. , Kuga Milton C. , Silva Lea A.B. , Rossi Marcos A.
Published: June 2021

Substances containing a combination of antibiotics have been investigated as intracanal medication although without precise establishment of their real effects on the biological systems. The aim of this study was to characterize the response of mouse subcutaneous connective tissue to triple antibiotic paste (TAP) consisting of metronidazole, ciprofloxacin and minocycline. Polyethylene tubes containing TAP or calcium hydroxide (CH) ‐ control group, were implanted in mouse subcutaneous tissue. After periods of 7, 21, and 63 days, the implants were subjected to histological processing and analyzes were performed. The gene expression of IL‐1β, TNF‐α, IL‐17, TGF‐β, VEGF and HIF‐1α was detected by real‐time PCR. The results were compared using Student's t test and ANOVA and Tukey's test (α = 0.05). TAP induced exuberant inflammatory and angiogenic response, with higher numbers of inflammatory cells, higher vascular area and density and lower relative percentage of collagen compared to CH. In general, the expression of genes involved in inflammation and angiogenesis was higher in the TAP group compared to CH. We concluded that the response of mouse subcutaneous connective tissue to TAP was characterized by persistent and exacerbated inflammatory and angiogenic responses along with absence of repair.

Financial support: Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP (11/19511–0) and PROPe ‐ UNESP.
ESTROGEN‐RESPONSIVE NEURONS IN THE MEDIAL AMYGDALA PREVENT STRESS‐INDUCED HYPERTENSION
Authors: Hinton Antentor Othrell , Xu Pingwen , Yan Xiaofeng , Reynolds Corey L. , Xu Yong
Published: June 2021

Background

Hypertension is the leading cause of cardiovascular disease worldwide. The etiology of essential hypertension is unknown. Psychological stress contributes to development of hypertension in humans. Estrogen has been shown to prevent stress‐induced hypertension in rodents with unknown mechanisms. Amygdala neurons have been implicated in controlling blood pressure. Abundant estrogen receptors, including estrogen receptor‐α (ERα), are expressed in the medial amygdala (MeA). Thus, we hypothesize that ERα expressed by MeA neurons mediates the anti‐hypertensive effects of estrogen during stress.

Methods

We use the Cre‐LoxP system to remove ERα from specific MeA neurons in mice (ERαlox/lox/SIM1‐Cre). Female ERαlox/lox/SIM1‐Cre mice and controls (ERαlox/lox) were subjected to bilateral ovariectomy (OVX), given a vehicle (V) or 17‐β‐Estradiol pellet (E2), and inserted with telemetry probes on day one. After a seven‐day recovery, blood pressure was recorded for 3 hours to establish baseline and then mice were subjected to 1 hour stress restraint.

Results

ERαlox/lox OVX + V mice showed increased mean arterial blood pressure (MAP) and systolic arterial blood pressure (SAP) in response to stress, whereas this stress‐induced hypertension was blunted in ERαlox/lox OVX + E mice. Interestingly, ERαlox/lox/SIM1‐Cre OVX + E and OVX + V group both showed increased MAP and SAP in response to stress.

Conclusions

Our results suggest that ERα in the MeA is required to mediate estrogenic actions to prevent stress‐induced hypertension.
Nitrous Oxide (N2O) Exposure Increases Neuronal Nitric Oxide Synthase (nNOS) Expression in Mouse Brain
Authors: Zhang Yangmiao , Koh David , Quock Raymond
Published: June 2021

N2O has been known to possess an analgesic property since the late 18th century. Since then, researchers have proposed different hypotheses for the mechanism, including an opioid/nitric oxide (NO) hypothesis (Emmanouil and Quock, Anesth Prog 54:9–18, 2007). Previously, we reported that N2O antinociception can be reduced by blocking NO production in the brain with selective nNOS inhibitor SMTC (Ishikawa and Quock, JPET 306:484–489, 2003). Recently, we found that increasing nNOS expression in brain contributes to HBO2 antinociception (Zhang et al., SfN Abstracts 38:575.29, 2012). The aim of this study was to discover whether N2O exposure also changes nNOS expression in the brain. Male NIH Swiss mice were exposed to 50% N2O for 60 min and sacrificed at intervals 0–8 hrs later. Brains were removed and divided into six coronal sections using a brain matrix. Expression of nNOS was examined by the western blotting assay. Results demonstrated that N2O treatment increased nNOS expression mostly in section 5 (−4.65 mm to −6.75 mm AP from bregma) and section 6 (−6.75 mm to −8.75 mm AP). The increase lasted for at least 8 hrs, which differs from HBO2‐induced nNOS expression that peaked at 6 hr. Based on these findings, we conclude that N2O exposure increased nNOS expression in the caudal mouse brain. (This research was supported by NIH Grant AT‐007222 and the Allen I. White Distinguished Professorship at Washington State University.)
Complex allosteric effects of amiodarone at M1 muscarinic receptors: signal sharpening
Authors: Stahl Edward , Elmslie Gwendolynne , Ellis John
Published: June 2021

We have previously reported that amiodarone interacts with a novel allosteric site on muscarinic receptors. At the M3 and M5 subtypes, the major effect of amiodarone is to enhance the maximal degree of response elicited by acetylcholine and other agonists, without significantly altering the potency of the agonist. The initial screening of the M1 subtype, at typical (EC20‐EC50) concentrations of agonist, revealed no effect of amiodarone. In the present study, we demonstrate that amiodarone does in fact enhance the maximal agonist effect at M1, but that a concomitant decrease in agonist potency obscures the effect at the screening concentrations of agonist that were previously used. These effects, at all three subtypes, are well‐explained as an interaction between the parameters for binding cooperativity and activation cooperativity in Hall's allosteric two‐state model (Mol Pharmacol 58:1412).

Furthermore, the effects of amiodarone on M1 receptor signaling illustrate the possibility of a new form of receptor modulation; we have named this modulation “signal sharpening”. The effect of signal sharpening occurs in the sense that responses above a certain magnitude are enhanced, while responses below that magnitude are reduced. We speculate that one way this type of modulation may be useful would be in regulating the contribution of transmitter spillover to extra‐synaptic signaling.

[Supported by PHS R01 05214]
Protective effect of protocatechuic acid of Momordica charantia from memory impairment induced by amyloid β25–35
Authors: Cho Eun Ju , Choi Jung Ran , Lee Sanghyun , Cho Kye Man , Kim Hyun Young
Published: June 2021

Alzheimer's disease (AD) may be caused by deposition of amyloid β‐peptide (Aβ) in plaques in brain tissue. We investigated the protective effect of protocatechuic acid on active phenolic compound from Momordica charantia, on cognition impairment under in vivo AD model of ICR mice induced by Aβ25–35. The damaged abilities of recognition and memory were occurred by the injection of Aβ25–35 in brain, and then the protocatechuic acid was administered orally for 2 weeks at dose 100 and 200 mg/kg body weight. To observe protective role from impairment of memory and cognition behavioral experiments of T‐maze, object cognition and Morris water maze tests were carried out. The abilities of novel object recognition and new route awareness were improved by the administration of protocatechuic acid as oral dose‐dependent manner. The result on Morris water maze test indicated that the groups administered reached more quickly protocatechuic acid the hidden platform than control group suggesting improvement of spatial perception ability. The present study supports the protective role of the protocatechuic acid against impairments of memory and cognition ability induced by Aβ under AD model of ICR mice
Effect of exercise training on ischemia‐reperfusion injury of steatotic livers from OLETF ratsι
Authors: Shibamoto Toshishige , Yamamoto Yuki , Kuda Yuhichi , Tanida Mamoru , Wang Mofei , Kurata Yasutaka
Published: June 2021

Exercise training is recommended to prevent the obesity‐associated disorders. However, it remains unknown whether exercise training attenuates ischemia‐reperfusion (I/R) injury of steatotic liver. We determined, using the hyperphagic, Otsuka Long‐Evans Tokushima Fatty (OLETF) rat and the control Long‐Evans Tokushima Otsuka (LETO) rat, effects of exercise training on I/R injury in perfused steatotic liver. Running training was given on a motorized treadmill for five weeks from 19‐th week. Livers from male exercise OLETF, exercise LETO, non‐exercise OLETF and non‐exercise LETO rats were perfused portally with diluted blood at a constant blood flow. Ischemia was induced by occlusion of the portal vein for 1 hour, followed by 1‐hour reperfusion in a recirculating manner. Liver injury was assessed by blood alanine aminotransferase (ALT) levels, bile flow rate and histology of the livers. I/R‐induced increase in blood ALT levels of OLETF rats was higher than that of LETO rats. Exercise training attenuated the increase in both body weight and liver weight, and liver cell degeneration in OLETF rats, as compared the corresponding non‐exercise OLETF rats. I/R‐induced ALT elevation tended to be smaller in exercise OLETF rats than in non‐exercise OLETF rats. Reduced bile flow rate were similar among rats studied. In conclusion, exercise training produces a marginal effect on I/R injury of steatotic livers from OLETF rats.
Cardiac ischemia reperfusion elicits increased mitochondrial mass but decreased mitochondrial respiration in mice
Authors: Kalogeris Theodore John , Wang Meifang , Korthuis Ronald J.
Published: June 2021

Modulation of mitochondrial biogenesis (MB) has been proposed to play a potentially critical role in the cardiac response to ischemia‐reperfusion (I/R), however, the specific effect of IR on MB has been little studied. We previously observed a significant increase in apparent cardiac mitochondrial mass after I/R in mice. Here we examined whether I/R‐induced increases in mitochondrial mass were associated with changes in mitochondrial respiratory activity. Mice were subjected to 30 occlusion of the left anterior descending coronary artery followed by 4 h reperfusion. Hearts were harvested for determination of both mitochondrial and nuclear DNA (mtDNA, nDNA, respectively) and measurement of respiratory activity in isolated mitochondria. The ratio of mtDNA/nDNA was increased 2–4‐fold by I/R. This was associated with significant decreases in both glutamate/malate‐ and succinate‐fueled oxygen consumption , as well as decreased respiratory control ratio (state3/state4). These results suggest that acute increases in mitochondrial biogenesis may be a compensatory but maladaptive response to I/R‐induced mitochondrial dysfunction, analogous to chronic mitochondrial cardiomyopathies. Supported by NIH AA‐014945 and HL‐095486.
Monocyte Recruitment during Microvascular Arteriogenesis is Induced by Altered Flow and Influenced by Proximity of Venules to Collateral Arterioles
Authors: Bruce Anthony , Meisner Joshua K. , Price Richard J. , Peirce Shayn M.
Published: June 2021

It has previously been shown that monocyte recruitment is required for arteriogenesis in large diameter collateral arteries following elevated shear stress induced by occlusion. Once recruited to the stimulated collateral vessel, these cells promote smooth muscle cell and endothelial cell proliferation through secreted cytokines. However, this recruitment has not been clearly demonstrated in collateral arterioles (≤100 microns in diameter) of the microcirculation and questions remain regarding the route by which these cells arrive (egress from arteriole vs. venule) in the microcirculation. We utilize laser speckle flowmetry to measure relative changes in blood flow velocity experienced by individual arteriole collaterals in the murine spinotrapezius muscle and ear following feeder arteriole occlusion. In addition, the effect of network architecture on these flow changes is investigated. Localized recruitment of fluorescent protein‐expressing monocytes in the CX3CR1‐eGFP transgenic mouse is observed around the mural cell layer of NG2+ collateral arterioles 3 days post‐ligation. Moreover, the orientation of venules in relation to shear‐activated collateral arterioles appears to influence which sites along the collateral arteriole remodel following elevated shear stress. Our results suggest that monocyte recruitment to remodeling collaterals following small arteriole occlusion is a result of altered blood flow and occurs preferentially at collateral sites which are in close proximity to a paired venule. Funding provided by NIH‐HL082838‐02.
Cardiovascular responses produced by activation of P2X purinergic receptors in the lateral parabrachial nucleus
Authors: De Paula Patricia M. , Menezes Miguel F. , Costa Mariana O. , Menani Jose V.
Published: June 2021

Recent studies have shown that purinergic mechanisms of the lateral parabrachial nucleus (LPBN) are involved in the control of sodium intake. In the present study, we investigated the effects of injections of α,β‐methylene adenosine 5′‐triphosphate (α,β‐meATP, a selective P2X purinergic receptor agonist) alone or combined with the P2X purinergic receptor antagonist PPADS (pyridoxalphosphate‐6‐azophenyl‐2′,4′‐disulfonic acid) into the LPBN on mean arterial pressure (MAP) and heart rate (HR) in awake rats. Male Holtzman rats (n = 6), baseline MAP = 102 ± 2 mmHg and baseline HR = 376 ± 10 bpm, with stainless steel guide‐cannulas implanted in the LPBN and with a polyethylene tubing (PE‐10 connected to a PE‐50) inserted into abdominal aorta through femoral artery were used. Unilateral injection of α,β‐meATP (2.0 nmol/0.2 μl) into the LPBN increased MAP (15 ± 2 mmHg, vs. saline: 4 ± 1 mmHg), without changing HR. The pressor response to α,β‐meATP injected into the LPBN was attenuated by previous injection of PPADS (4.0 nmol/0.2 μl) into the LPBN (3 ± 1 mmHg). Unilateral injection of PPADS alone into the LPBN produced no change on baseline MAP and HR. The results suggest that α,β‐meATP acting on P2X purinergic receptors in the LPBN produces pressor responses without changing HR. Financial support: FAPESP, CNPq.
Role of nucleus tractus solitarii (nTS) hydrogen sulfide (H2S) in hindlimb unloaded rats
Authors: Hasser Eileen M , Heesch Cheryl M , Kline David D
Published: June 2021

Cardiovascular deconditioning alters central cardiorespiratory regulation and is mimicked by hindlimb unloading (HU). Preliminary data suggest the ventilatory response to hypoxia is augmented in HU rats. Furthermore, H2S from cystathionine beta synthase (CBS) augments excitatory neurotransmission in nTS, the initial site for cardiorespiratory sensory integration. Preliminary studies suggest nTS H2S augments phrenic (PNA) and splanchnic sympathetic (sSNA) nerve activity during acute hypoxia (AH) but its influence in HU rats is unknown. To test the hypothesis that increased endogenous H2S from CBS in the nTS enhances cardiorespiratory responses to AH after HU, we examined mean arterial pressure (MAP), PNA and sSNA responses to AH (2 min; 10% O2). Baseline cardiorespiratory parameters were similar in anesthetized control (C) and HU rats. Chemoreflex activation with AH increased PNA and sSNA and decreased MAP in both groups; the depressor response was less in HU rats. Bilateral nTS microinjection of the CBS inhibitor aminooxyacetate (AOA; 1 mM, 90 nl), to decrease H2S, increased baseline MAP and sSNA in both groups. In the presence of AOA, the increase in PNA amplitude to AH tended to be blunted in CC rats; this attenuation appeared to be less in HU. AOA did not alter the sSNA response to AH in CC rats, but reduced sSNA during AH after HU. These preliminary data suggest that CBS‐derived H2S in nTS augments cardiorespiratory responses to hypoxia and this modulation is diminished after HU. HL55306
The Role of Cardiorespiratory Fitness and Central Arterial Pressure in Age‐Related Reduction in Brain Volume
Authors: Tarumi Takashi , Ayaz Muhammad , Parker Rosemary , Tinajero Cynthia , Zhang Rong
Published: June 2021

Emerging evidence suggests that vascular risk factors accelerate but physical activity attenuates age‐related decline in cognitive function which may be related to changes in brain volume.

Purpose

To determine whether maximal aerobic capacity, central blood pressure and arterial stiffness moderate age‐related changes in brain volume.

Methods

18 young (30±1 years), 27 middle‐aged (51±1 years), and 17 older (67±1 years) adults underwent measurements of cognitive function, maximal oxygen consumption (VO2max), central blood pressure, arterial stiffness, and brain MRI.

Results

Age was significantly correlated with lower levels of memory recall (r=−0.43) and VO2max (r=−0.72) and higher levels of central systolic and pulse pressures (both r=0.57) and arterial stiffness (r=0.62) (all P<0.05). Gray matter volume of neocortex, subcortex, and cerebellum, were negatively correlated with age (r=−0.40~−0.76, all P<0.05). In middle‐aged and older subjects, multiple regression analysis adjusted for age and sex revealed that VO2max is positively associated with parietal cortical thickness (β=0.50, P<0.05) and that central systolic blood pressure is negatively associated with subcortical gray matter volume (β=−0.31, P<0.05).

Conclusion

Greater maximal aerobic capacity and lower central systolic blood pressure may attenuate age‐related reductions in brain tissue volume.
Daily spontaneous running (DSR) decreases phosphorylation of left ventricular (LV) connexin‐43 (Cx43) at pathological sites in female Sprague‐Dawley rats
Authors: Mulvey Jillane , Firkins Rachel M. , Moffitt Julia A. , Henry Matthew K.
Published: June 2021

Cx43 is a gap junction expressed primarily in the LV of the heart that ensures efficient cell to cell communication. Down‐regulation of gap junctions often correlates with a pathological cardiovascular state, including ischemia and increased arrhythmogenesis. Regulation of Cx43 protein by post‐translational modification can enhance or down‐regulate gap junction assembly and function. Cardiovascular conditioning via exercise training has been well documented to prevent the incidence of arrhythmias. The goal of this study was to determine if DSR resulted in altered LV‐Cx43 expression and/or phosphorylation status. We hypothesized that cardiovascular conditioning with exercise training would elicit a reduced phosphorylation at sites known to decrease Cx43 function (S255, S262, S279/282, and S368). To simulate a conditioned state, rats underwent 9 weeks of DSR (n=4), compared to cage controls (n=4). Subsequently, Western blot analysis was performed to measure total and phosphorylated forms of Cx43 from the LV. Data indicate no change in Cx43 expression. However, the phosphorylation status was altered by DSR, with the greatest impact on S368. Specifically, there was a significant decrease in hyperphosphorylated Cx43‐pS368. Thus, cardiovascular conditioning with exercise may alter Cx43 phosphorylation status in a manner consistent with a cardioprotective effect against arrhythmogenesis. IOER‐3726.
Prolonged Fasting Induces Insulin Resistance in the Northern Elephant Seal Pup
Authors: Viscarra Jose A , Crocker Daniel E , Ortiz Rudy M
Published: June 2021

Northern elephant seal pups fast for 2–3 months post‐weaning during which they show various symptoms associated with insulin resistance (e.g. reduced glucose clearance and insulin signaling, and increased plasma lipids). However, because fasting pups also show decreased plasma insulin, it remains unclear whether or not decreased insulin action is a result of decreased insulin sensitivity. To address the hypothesis that fasting induces insulin resistance in elephant seal pups, early (n=5) and late (n=5) fasted seals were infused with a mass specific dose of insulin (0.065 U/kg). Glucose clearance was similar in both periods (1.08 mg/dL/min vs. 1.05 mg/dL/min), however insulin‐signaling activity was 15% lower in late fasted seals. Plasma lipids were decreased to a greater degree in the early fasted seals than in late fasted seals. Glucose clearance of fasting pups is 70% slower than seen in insulin sensitive mammals. Additionally, reduced insulin signaling activity paired with reduced inhibition of lipolysis in late fasted seals demonstrates that insulin sensitivity declines further with fasting. These results definitively show that fasting elephant seal pups are insulin resistant. Furthermore, because fasting, insulin resistant pups are able to maintain control of their metabolism, these results strengthen the idea that insulin resistance is an adaptation to prolonged fasting.
Intragastric ketone ester administration prevents CNS oxygen toxicity (CNS‐OT) and modulates tidal volume and respiratory frequency in rats
Authors: Pilla Raffaele , D'Agostino Dominic P , Landon Carol S. , Dean Jay B.
Published: June 2021

In clinical and military operations, hyperbaric oxygen (HBO) can generate central nervous system oxygen toxicity (seizures). In a previous study, we demonstrated that the intragastric administration of ketone ester (KE), a non‐ionized ketone bodies precursor, has a prominent anti‐seizure effect. In this follow‐up study, we tested the anticonvulsant properties of multiple KEs, and their effects on cardio‐respiration.

60 male rats were implanted with radio‐telemetry devices to record EEG, diaphragmatic electromyogram (dEMG) and ECG. Rats were orally administered with one of four KEs: beta hydroxybutyrate, R,S‐1,3‐butanediol, acetoacetate monoester (AcAc), and acetoacetate diester (AcAc2). 30 min later, rats were exposed to HBO at 5 atmosphere absolute, until the onset of CN‐SOT, and the latency to seizure (LS) was measured.

Our results showed that: a) AcAc2 was found to be the most potent anticonvulsant ester, as it increased the LS of 574%, compared to controls; b) AcAc and AcAc2 administration caused a significant increase in tidal volume (VT) and thus minute ventilation c) while stabilizing respiratory frequency (fresp) between 15 min before and after seizure, compared to controls.

We report that 1) KEs (notably AcAc and AcAc2) increase the animal's resistance to seizures, and 2) ventilation (VT and fresp) was significantly stimulated by the oral administration of KEs.
Intrapleural CTB‐saporin selectively kills phrenic motor neurons: a motor neuron disease model
Authors: Nichols Nicole Louise , Vinit Stephane , Mitchell Gordon S
Published: June 2021

Amyotrophic lateral sclerosis (ALS) is a devastating disease leading to progressive motor neuron degeneration and ultimately, ventilatory failure. In a rodent model of ALS (SOD1G93Arats), ventilatory capacity is preserved despite >;50% loss of phrenic and intercostal motor neurons (i.e. compensatory respiratory plasticity preserves breathing capacity). Here, our intent was to develop an experimental model to study compensatory plasticity without many of the complications attendant to ALS. Thus, we tested the hypothesis that intrapleural injections of cholera toxin B fragment conjugated to saporin (CTB‐SAP) selectively kill respiratory motor neurons to mimic motor neuron death in ALS. Phrenic motor output was assessed in anesthetized, paralyzed and ventilated Sprague Dawley rats 3–28 days following bilateral intrapleural injections of: 1) CTB‐SAP (25–50μg), or 2) un‐conjugated CTB and SAP (control). CTB‐SAP elicited dose‐dependent phrenic motor neuron death; 25μg CTB‐SAP (7 days) most closely resembled cell death in end‐stage (ES) ALS rats (36±7% survival; n=9; p<0.05 vs. controls); CTB‐SAP diminished phrenic motor output (CTB‐SAP: 0.3±0.07 volts vs. Control: 1.5±0.3; n=9; p<0.05) to a level resembling ES ALSrats (0.4 volts). Intrapleural CTB‐SAP injections represent a novel inducible and repeatable model to study the impact of respiratory motor neuron death on breathing.

[Supported by NIH NS057778 and HL080209 and the Francis Families Foundation]
Selective contribution of inflammation and oxidative stress to the cardiorespiratory and carotid body alterations following intermittent hypoxia
Authors: Del Rio Rodrigo , Moya Esteban A , Iturriaga Rodrigo
Published: June 2021

Chronic intermittent hypoxia (CIH), a main feature of obstructive sleep apnea, potentiates carotid body (CB) chemosensory and ventilatory hypoxic responses, and induces hypertension. These alterations are attributed to oxidative stress, since antioxidants prevent the enhanced chemosensory and ventilatory hypoxic responses and the hypertension. We tested if oxidative stressinduced upregulation of pro‐inflammatory cytokines TNF‐α and IL‐1β are involved in the CB and cardiorespiratory alterations during CIH. We studied the effects of ibuprofen (40 mg/Kg day) on TNF‐α, IL‐1β and 3‐nitrotyrosine (3‐NT) CB levels, chemosensory and ventilatory hypoxic responses, and blood pressure in male Sprague‐Dawley rats exposed to CIH (5%O2, 12 times/h for 8 h/day) for 21 days. CIH increased CB TNF‐α, IL‐1β and 3‐NT, enhanced chemosensory and ventilatory hypoxic responses, and led to hypertension. Ibuprofen prevented the increased TNF‐α and IL‐1β CB levels and cardioventilatory alterations, but not the enhanced chemosensory hypoxic response and 3‐NT accumulation. Contrarily, ascorbic acid prevented the increased CB cytokines and 3‐NT expression, the chemosensory and ventilatory potentiation, and the hypertension. Thus, present results show that CIH‐induced potentiation of CB chemosensory responses to hypoxia depends critically on the oxidative stress, but not on the increased TNF‐α and IL‐1β in the CB. Thus, we provide new evidence suggesting a plausible role for pro‐inflammatory cytokines in the control of breathing and arterial pressure during CIH acting through a CB independent pathway.

Supported by FONDECYT 1100405
CNS Region‐Specific Microglial Activation Following Intermittent Hypoxia: Role of Endogenous Ligands and TLR4
Authors: Smith Stephanie MC , Wessel Alex W , Huxtable Adrianne G , Mitchell Gordon S , Watters Jyoti J
Published: June 2021

Intermittent Hypoxia (IH), a hallmark of sleep apnea, causes severe neurologic deficits. Inflammation underlies much IH‐induced neuropathology, including cortical/hippocampal neuronal apoptosis and obliteration of phrenic long‐term facilitation, a form of spinal respiratory motor plasticity. We tested the idea that microglial responses to IH differ by CNS region and that the presence of soluble, IH‐induced toll‐like receptor 4 (TLR4) ligands play a role. Animals were treated with 8–12hrs of IH or normoxia for 1–14 days. Various CNS regions were harvested, dissociated, and pelleted for immunomagnetic isolation of microglia. Soluble IH‐induced factors remained in the sample supernatants. Microglial activation was assessed by flow cytometry and/or qRT‐PCR and was found to differ by CNS region. To investigate the mechanism whereby IH activates microglia, we treated microglial cultures with CNS supernatants. The soluble factors from IH‐treated animals induced activation of cultured microglia, pro‐inflammatory effects that were absent in microglia with nonfunctional TLR4. These data suggest that endogenous molecule(s) released during IH may signal through TLR4 to promote microglial activation and neuroinflammation in vivo. This is the first study to demonstrate regional differences in microglial inflammatory responses to IH, and to investigate their mechanistic underpinnings.
Estradiol increases plasma membrane insertion of αENaC in the lung
Authors: Greenlee Megan M. , Mitzelfelt Jeremiah D. , Yue Qiang , Duke Billie Jeanne , Eaton Douglas C.
Published: June 2021

Sodium reabsorption through alveolar epithelial sodium channels (ENaC) is the major driving force for lung fluid clearance. Recent evidence shows greater rates of lung fluid clearance in females than males suggesting that female sex hormones might regulate ENaC function. Using cell‐attached patch clamp, we have previously shown that β‐estradiol (E2) activates both highly‐selective and non‐selective ENaC in rat alveolar cells (L2). To extend that study, we examined possible mechanisms by which E2 increases ENaC activity. We first investigated whether E2 (200 pg/mL) altered αENaC gene expression in alveolar (L2) cells. E2 did not affect mRNA or protein levels of αENaC. Using cell surface biotinylation, we also examined differences in apical plasma membrane abundance of αENaC in vehicle and E2‐treated cells. There was ~3 fold increase in αENaC (60kDa) abundance with E2 treatment. Finally, we examined plasma membrane abundance of αENaC in lungs from female rats at the diestrus, proestrus, and estrus phases of the estrous cycle. Consistent with an effect of E2, we observed ~3 fold greater abundance of αENaC (60–75kDa) in lungs from proestrus rats. These results suggest that greater insertion of αENaC into the plasma membrane is one mechanism by which E2 increases alveolar ENaC activity. Future studies will focus on which estrogen receptor mediates this effect.

Funding: NIH R37DK037963, K12GM000680 and T32HL076118
Influence of Early Growth Response 1 (Egr1) and Tenascin C (Tnc) on compensatory lung growth
Authors: Rauschkolb Peter Michael , Wolff Jens Christian , Morty Rory , Seeger Werner , Voswinckel Robert
Published: June 2021

Mice that underwent a unilateral pneumonectomy (PNX) show complete restoration of pulmonary function through a rapid and complete compensatory growth of the remaining lung. Currently there is still little known about the nature, initiation and modulation of such growth. Microarray studies showed an upregulated expression of the immediate early gene Egr1 and the matricellular protein Tnc after PNX. In this study we assess the role of Egr1 and Tnc in early stages of compensatory lung growth.

Stereology analysis of tissue sections showed that lungs of Egr−/− mice have the same surface area but less alveoli and a larger lung volume compared to wild type mice. During compensatory lung growth the loss of Egr1 seems to lead to a delayed regeneration of alveolar surface area whereas lung volume increases faster. Stereological analysis of Tnc−/− mice showed that these mice also have a larger lung volume compared to wild type mice. After PNX regeneration of alveolar number and lung volume is impaired.

The results indicate that Egr1 and Tnc seem to have an influential role in the initial phases of compensatory lung growth. Additional experiments will be done to clarify how these genes are regulated after PNX. German research foundation.
Influence of Lung Volume, Fluid and Capillary Recruitment during Positional Changes and Exercise on Thoracic Impedance in Heart Failure
Authors: Kim Chul‐Ho , Fuglestad Matthew A. , Richert Malie L Ceridon , Shen Win‐Kuang , Johnson Bruce D
Published: June 2021

Introduction

Optivol (Medtronic Inc.) thoracic impedance (ZT) provides preemptive disease status information in heart failure (HF). It remains unclear how pulmonary‐capillary blood volume (Vc), lung volume (Lvol), and interstitial fluid influence ZT.

Hypothesis

Positional change and exercise result in increased Vc and/or lung interstitial fluid and ZT tracks fluctuation in these variables.

Methods

12 HF patients (age 63±8yr, LVEF 41±14%) were recruited. Measures were taken at rest, exercise, recovery. This included: spirometry, ZT, diffusing capacity of the lungs for CO and NO (DLCO, DLNO), alveolar‐capillary conductance (Dm, interstitial fluid index), and Vc. Inspiratory capacity was obtained to provide consistent lung volumes for assessing ZT.

Results

Positional change (upright‐supine) resulted in an increased ZT (5±4%, p<0.01), while the change in Lvol (RV‐TLC) resulted in a 7±2 ohm swing in ZT (0.2±0.1ohm change/100ml change in Lvol). After 30min supine, Vc increased 28±39% (p<0.05) while Dm/Vc and Lvol decreased (29±11% and 17±3%, p<0.05). During exercise compared to baseline, Vc increased 56±44% (p<0.01), DmCO/Vc decreased 25±7% (p<0.05), and ZT did not change. During recovery measures normalized except DmCO/Vc.

Conclusion

Positional changes and fluctuations in Lvol influence ZT yet measures of lung fluid minimally impact this measure despite significant fluctuations.
Dopamine and Angiotensin II effect on Na,K‐ATPase in FXYD2 presence
Authors: Cortes Vanessa Faria , Mendes Graciela C , Valadares Jessica M M , Cobal Sabrina A , Fontes Carlos F L , Barbosa Leandro A
Published: June 2021

The FXYD2 is a single span membrane protein that are describe to regulate the Na,K‐ATPase. In this study we demonstrated that the dopamine can inhibit Na,K‐ATPase from kidney medulla in about 33%, and that the addition of an excess of FXYD2 reverse this. PKC and PKA inhibitors also protect the Na,K‐ATPase from dopamine inhibition and we did not observed any additional protection when the FXYD2 was added. We also observed that HeLa cells viability in presence of dopamine (1μM) is reduced in 20 %, however, when FXYD2 was added, the cells viability were restored up to 15%. The angiotensin II (10 pM) activates Na,K‐ATPase from kidney medulla in 25% and in presence of an excess of FXYD2 this activity was incremented in 45%. When FXYD2 was incubated with erythrocytes we did not observed angiotensin effect on Na,K‐ATPase activity, however when FXYD2 was added we observed an effect similar to Na,K‐ATPase from kidney medulla in presence of angiotensin II. In this work we showed that the FXYD2 seems to have an important participation on hormonal signal by dopamine and angiotensin, modulated Na,K‐ATPase activity. This study was supported by Fapemig and UFSJ.
Structural contribution of intravascular blood distension to lung mechanics
Authors: Gibney Barry C , Ackermann Maximilian , Ysasi Alexandra , Belle Janeil , Tsuda Akira , Konerding Moritz , Mentzer Steven
Published: June 2021

To investigate the contribution of blood vessels to lung mechanics, we studied normal mice and mice after varying degrees of parenchymal resection. Pulmonary mechanics, including multi‐frequency lung impedance studies, were performed in open‐chest control mice (normal blood volume) and acutely exsanguinated mice. As expected, the presence or absence of blood had no effect on central airway resistance (p>;.05). In contrast, measures of tissue damping (G), tissue elastance (H) and hysteresivity (η) demonstrated a significant increase in bloodless mice (p<.001). After surgical resection, the absolute difference in G and H between normal and exsanguinated mice increased with the amount of parenchymal resection; however, the proportional contribution of blood was identical in all conditions. The presence of blood in the pulmonary vasculature resulted in a constant 64±5% reduction in tissue damping (G) and a 55±4% reduction in tissue elastance (H). To identify a distinct structural subset of vessels in the lung potentially contributing to these observations, vascular casting and scanning electron microscopy of the lung demonstrated morphologically distinct vascular rings at the alveolar opening. Our results suggest that an intravascular blood distension, likely attributable to a subset of vessels in the alveolar entrance ring, contributes a measurable scaffolding effect to lung function.
Terms that move us: Striding through the intersection of anatomy and biomechanics
Authors: Greiner Thomas M.
Published: June 2021

Terminologia Anatomica provides an incomplete list of terms used to describe movements (A03.0.00.055 ‐ A03.0.00.063). These terms are generally thought to be well understood. Yet, they have no standardized definitions. Descriptions of movement are based more on linguistic tradition than upon anatomical or kinematic convention. Although this may seem trivial, it can lead to several unintended contraindications and miscommunications in clinical, biomechanical and functional anatomical applications. This presentation will provide examples of some problems that occur when applying these terms to movements of the foot and ankle.

The foot is constructed with a series of ligaments that link adjacent bones. This insures that no foot joint moves in isolation. Similarly, there are no foot muscles that cross and act upon a single joint. Therefore, every motion of the foot is a complex multi‐joint motion. But, the available terms of movement do not account for this complexity. Instead, the same term is frequently used to describe motion for a single joint and for whole foot movements. This creates a conundrum. A term that describes the movement of the whole foot should not similarly describe the complex and varied movements that occur in several joints simultaneously. We have no way to clearly describe and communicate individual joint or whole foot movements.
Fascicle morphometry of the recurrent laryngeal nerve in short term experimental diabetes.
Authors: Mendes Vânia Alice Aguiar , Silva Greice Anne Rodrigues , Castania Jacy Airton , Salgado Helio Cesar , Fazan Valéria Paula Sassoli
Published: June 2021

Previous results from our laboratory [1] showed that 50% of the aortic depressor nerves (ADN), the afferent arm of the baroreflex, show alterations in early stages of induced diabetes in rats. The recurrent laryngeal nerves (RLN) are known to contain barorreceptor fibers as well and there are no reports on the morphology of the RLN in short term diabetes. Male Wistar rats received a single intravenous streptozotocin injection and control rats received vehicle. On the 15th day after the injections, rats were anesthetized for arterial pressure (AP) and heart rate (HR) recordings, prior to RLN removal. Proximal and distal segments of the right and left RLN were prepared for light microscopy morphometry, carried out with the aid of a computer software. Body weight increased significantly on the control s(309 ± 9 g) compared to the diabetics (200 ± 4 g). As expected, blood glucose levels were significantly high in the diabetic animals. Both the AP and HR were reduced in the diabetic group, attaining significant difference on the HR values. Fascicle morphometry parameters were not different between groups. We suggest that 15 days was not long enough to trigger detectable differences in the RLN fascicles. This difference with our previous findings in the ADN is probably due to the nerve size, since the ADN is much smaller than the RLN.