bluuebunny/crossref_metadata_2025 huggingface dataset:
Activation of the Calcium Sensing Receptor potentially inhibits Kv1.5 channel activity
Authors: Ayon Ramon J , Tang Haiyang , Yee Allison M , Dash Swetaleena , Ek‐Vitorin Jose F , Makino Ayako , Yuan Jason X.‐J.
Published: November 2023

The Calcium sensing receptor (CaSR) is class of G protein coupled receptors (GPCR) that can be activated by extracellular Ca2+ and Mg2+. Activation of CaSR can stimulate the phospholipase C (PLC) signaling pathway that leads to synthesis of inositol 1,4,5 triphosphate (IP3) and diacylglycerol (DAG). Voltage‐gated potassium (Kv) channels activity is essential for establishing resting membrane potential in a variety of cell types including pulmonary artery smooth muscle cells (PASMC). Indeed, stimulation or inhibition of K+ channels can easily determine cell fate, as K+ channel activity is associated with cell proliferation, survival and apoptosis. It has been reported that some K+ channel classes are regulated by GPCRs. For example, Kv1.2, and members of the two‐pore domain K+ channel family (TASK‐1 and TASK‐3) were shown to be inhibited by GPCR activation. Interestingly, Kv1.5 channel activity can also be suppressed by stimulation of GPCR via the Src tyrosine kinase pathway. However there are no reports to date that have shown any functional interaction between CaSR and Kv1.5. In this present study, we examined the effects of CaSR activation on Kv1.5 channel activity by transfection of KCNA5, which encodes for the Kv1.5 pore‐forming α subunit, alone or cotransfection of KCNA5/CaSR in HEK293 cells. Overexpression of KCNA5 and CaSR/KCNA5 in HEK293 cells were confirmed by Western blot and Immunofluorescence. Kv1.5 current amplitude (IKv1.5) was significantly attenuated by 1.8 mM external Ca2+ in cells transfected with both CaSR/KCNA5 but not in cells transfected with KCNA5 alone. To determine whether this Ca2+ induced decrease of IKv1.5 was due to activation of PLC‐DAG‐IP3 signaling cascade we used the PLC inhibitor U‐73122. Preliminary data showed that 10uM U‐73122 was capable of antagonizing the external Ca2+ induced decrease in IKv1.5. This would suggests that activation of CaSR by way of external Ca2+ is capable of inhibiting Kv1.5 channel activity via PLC signaling pathway

Support or Funding Information

Research supported by NIH Grants (HL115014, HL066012 and HL098053).
Characterization of Respiratory Activity in Spontaneously Breathing Urethane‐Anesthetized 6‐OHDA SN‐lesioned Parkinson's Disease Rat Model
Authors: Solomon Irene C , Collins William F
Published: November 2023

Respiratory dysfunction in Parkinson's Disease (PD) patients manifests as a variety of altered breathing patterns that are suggested to result from impairment of central respiratory control. To date, only a limited number of studies have used a rat PD model to begin to explore respiratory aspects of PD. Therefore, to better characterize the respiratory phenotype of PD, we have begun a series of experiments in the 6‐hydroxydopamine (6‐OHDA) neurotoxin‐induced unilateral SN lesion rat model. For these experiments, spontaneously breathing urethane‐anesthetized rats are being exposed to room air (basal conditions) and either hypoxic (12% O2) or hypercapnic (7% CO2) gas, and inspiratory‐related (tongue and/or diaphragm), and in some cases expiratory‐related (external oblique), EMG activity are recorded. Our preliminary data indicate that compared to control rats, SN‐lesioned rats (at 1‐week or 1‐month post‐lesion) exhibited (1) significantly higher basal breathing frequencies; (2) a similar increase in frequency, but a variable increase in the magnitude of the amplitude response to hypoxia; and (3) a slightly enhanced increase in breathing frequency and amplitude in response hypercapnia. These preliminary observations suggest that (1) the 6‐OHDA‐lesioned rat/rodent is a viable model for studying respiratory abnormalities in PD and (2) PD may differentially affect hypoxic and hypercapnic ventilatory responses.

Support or Funding Information

Thomas Hartman Center for Parkinson's Research at Stony Brook University
Tauopathy Induced Progressive Cell Loss of FoxP2‐Expressing Neurons in the Kölliker‐Fuse nuclei (KFn) is Tightly Linked to Clinically Relevant Laryngeal Dysfunction in Tau‐P301L Mice
Authors: Dutschmann Mathias , Bautista Tara , Bondarenko Evgeny , Nalivaiko Eugene , Stanic Davor
Published: November 2023

The developmental transcription factor FoxP2 is a highly reliable marker for the pontine KFn. The KFn have important function in the control of laryngeal adductor function during breathing and during a variety of upper airway motor behavior (e.g swallowing, vocalization).

Immunohistochemistry for FoxP2 and hyperphosphorylated Tau protein in an established mouse model of tauopathy (Tau P‐301L) indicates: (i) early onset tauopathy (age 3–5 months) occurs in the KFn region of otherwise non‐symptomatic Tau‐P301L mice; (ii) early KFn tauopathy can be identified before the onset of severe cognitive and/or motor dysfunction by an impaired sniff pattern in plethysmographic recordings in awake animals after exposure to trigeminal and non‐trigeminal odors (n=18); (iii) with aging, a progressive cell loss of FoxP2‐expressing neurons of the KFn can be detected. At terminal stages of 8–9 months old Tau‐P301L, a high percentage of the FoxP2‐expressing cells disappeared. The progressive cell loss in KFn correlates with emerging laryngeal dysfunctions which are in particular expressed as a dysphagia phenotype. As reported previously also the breathing pattern indicates progressively shows paradoxical inspiratory laryngeal adduction (Dutschmann et al., 2010). WE conclude that tauopathy linked neurodegeneration of KFn neurons may significantly contribute to upper airway disorders such as dysphagia mutism and paradoxical vocal cord motion seen in a variety of neurodegenerative diseases such as Alzheimer's disease Parkinsonism, frontotemporal dementia and motor neuron disease.

Support or Funding Information

The work was supported by ARC future fellowship and the Florey Institute for Neuroscience and Mental Health
Dietary Fiber and Exercise: Effects on Muscle Function, Cognition, and Short‐Chain Fatty Acids in Mice
Authors: Pence Brandt D. , Bhattacharya Tushar K. , Rytych Jennifer L. , Park Pul , Allen Jacob M. , Sun Yi , McCusker Robert H. , Kelley Keith W. , Johnson Rodney W. , Rhodes Justin S. , Woods Jeffrey A.
Published: November 2023

Short chain fatty acids (SCFAs) contribute to immune and brain function and are produced by gut bacteria through metabolism of fermentable fiber. We examined the relationship between dietary fiber and changes in cognition, muscle function, and cecal SCFA content with or without voluntary exercise in mice. Six‐week old male C57Bl/6J mice were fed AIN‐93M diet (Ctrl) or AIN‐93M with 5% pectin (Pect) substituted for cellulose for 6 weeks and voluntarily exercised on a wheel (VWR) or remained sedentary (SED), constituting 4 groups of N=5/group (Ctrl‐Sed, Ctrl‐VWR, Pect‐Sed, Pect‐VWR). Mice underwent a battery muscle and cognitive function testing after 4 weeks of feeding, and at sacrifice, we collected cecal contents for quantitation of SCFAs. VWR did not affect body weight over the course of the intervention, while Sed mice gained 2 grams (p<0.001, time*VWR). Neither VWR or dietary fiber type affected performance on the active avoidance task or Morris Water Maze task. Interestingly, both dietary fiber and VWR decreased grip strength, although only the pectin effect remained after normalization to body weight (p=0.004). VWR unsurprisingly increased performance on the rotarod (p=0.028) and exhaustive fatigue test (p=0.012). Pectin increased cecal concentrations of SCFAs acetate (p=0.001), propionate (p=0.002), and butyrate (p=0.005). Interestingly, VWR significantly increased acetate (p=0.030), and there was a significant VWR effect (p=0.002) and VWR*fiber interaction (p=0.031) such that the pectin + VWR group had the highest concentration of cecal propionate. In conclusion, pectin and/or VWR did not affect cognitive function but increased cecal SCFAs in young mice. These results may have implications for nervous system and immune functions.

Support or Funding Information

Funded by the Abbott‐UIUC Center for Nutrition, Learning, and Memory
Moderate Intensity Dynamic Resistance Training Induced Cardiovascular Benefits in Female Hypertensive Rats
Authors: Araujo Amanda , Bernardes Nathalia , Dias Danielle , Mello Tafne , Costa Gabrielly , Brito Janaina , Irigoyen Mária Cláudia , De Angelis Kátia
Published: November 2023

The dynamic resistance training (DRT) has been the subject of recent studies, however studies using post menopausal women or hypertensive women controlled by pharmacological treatment focusing just on metabolic parameters. Few studies evaluated the chronic effects of this type of training in blood pressure (BP) with direct measurement in untreated hypertensive females. The objective of this study was to evaluate the effects of DRT on BP, physical capacity and muscle weight in spontaneously hypertensive rats. Thus, we used 14 adult females SHR, divided into two groups (n = 7): sedentary females (FS) and trained females (FT). Maximal exercise testing was conducted before and after the training period. The DRT in moderate intensity (40–60% of the maximal load) was performed in a ladder adapted for rats per 8 weeks. After this period, there were blood glucose and triglyceride measurements and we performed cannulation of the carotid artery for direct measurement of BP. Heart tissue and soleus, plantaris and gastrocnemius muscles were weighted. There was improvement in physical capacity in the FT group (Maximum exercise test pre 192.75 ± 12.19 vs. post 471.13 ± 27.23). There were no difference in heart rate (FT: 386.04 ± 11.85 vs. FS: 371.93 ± 12.19 bpm) and metabolic evaluations (blood glucose 103.00 ± 1.94 vs. 102.25 ± 2.78 mg/dl; triglycerides: 112.00 ± 3.71 vs 122.25 ± 8.37 mg/dl, FT vs. FS respectively). Moreover, there were no differences in the weight of the gastrocnemius muscle (p = 0.928) and right ventricle (p = 0.549) between studied groups. DTR induced reduction in mean, systolic and diastolic BP (mean: 164.78 ± 4.96 vs. 179.20 ± 2.61; systolic: 188.97 ± 5.02 vs. 203.33 ± 4.11; diastolic: 142.67 ± 6.80 vs. 156.83 ± 2.29 mmHg, FT vs. FS respectively). Additionally, FT rats presented increased soleus and plantaris muscles and left ventricle weights as compared to FS rats (p <0.05). We conclude that the moderate intensity DRT induced BP reduction associated with cardiac hypertrophy, suggesting a positive role of this approach to hypertension management in females.

Support or Funding Information

FAPESP 2015/10329‐5, CNPq 457200/2014‐6, CAPES 88881.062178/2014‐1
Effect of Aging on the Inspiratory Muscle Metaboreflex
Authors: Smith Joshua R , Broxterman Ryan M , Hammer Shane M , Alexander Andrew M , Didier Kaylin D , Barstow Thomas J , Kurti Stephanie P , Harms Craig A
Published: November 2023

Activation of the inspiratory muscle metaboreflex leads to increased sympathetic outflow, mean arterial pressure (MAP), limb vascular resistance (LVR), and decreased limb blood flow. With aging, the skeletal muscle metaboreflex has been reported to be attenuated, similar, or exaggerated compared to younger adults. However, it is not known if aging influences the inspiratory muscle metaboreflex.

Purpose

The purpose was to determine if aging influences the inspiratory muscle metaboreflex in healthy humans. We hypothesized that compared to younger adults, older adults would exhibit less of: 1) an increase in MAP and diastolic blood pressure (DBP), 2) a decrease in limb blood flow, and 3) an increase in LVR.

Methods

Sixteen healthy older (M:2/W:6; 65.3 ± 5.5 yrs) and young (M:2/W:6; 22.3 ± 2.9 yrs) adults were recruited for this study and visited the laboratory on three different occasions. All young women were tested during the early follicular phase of their menstrual cycle and all older women were post‐menopausal. On the first visit, subjects were familiarized with all procedures and measurements. The next two visits were randomized and subjects performed an inspiratory resistive breathing task (IRBT) at ~2% or ~70% of their maximal inspiratory mouth pressure (PImax) for 20 min. During the IRBTs, the breathing frequency was 20 breaths per min with a 0.5 duty cycle. At rest and during the IRBTs, blood pressure was measured via automated oscillometry, femoral artery blood flow (FABF) was measured via Doppler ultrasound, end tidal CO2 was continuously monitored, and LVR was calculated MAP divided by FABF. Surface EMGs were placed on the leg to ensure no muscle contraction occurred.

Results

During the 20 min at ~70%PImax, older adults had a greater (p<0.05) increase in MAP (O: 12.1 ± 4.1% vs. Y: 2.3 ± 4.1%), SBP (O: 16.1 ± 12.6% vs. Y: 5.7 ± 4.9%), and DBP (p=0.06) (O: 9.0 ± 10.6% vs. Y: 0.6 ± 5.2%) compared to young adults. No differences (p>0.05) were present in HR or FABF (O: −13.6 ± 12.0% vs. Y: −7.3 ± 7.3%) over the 20 min. However, older adults had a greater increase in LVR compared to young adults (O: 33.5 ± 19.9% vs. Y: 13.9 ± 12.3%).

Conclusion

These data suggest that aging leads to an exaggerated inspiratory muscle metaboreflex in healthy humans.
Whole‐Body Heat Loss is Enhanced in Older Adults Following a Summer in a Humid Continental Climate
Authors: Poirier Martin P. , Dervis Sheila , Flouris Andreas D. , Kenny Glen P.
Published: November 2023

It has recently been shown that older adults have a reduced capacity to dissipate heat during exposure to extreme heat compared to their younger counterparts, resulting in a 1.7‐fold greater increase in body heat storage. However, it currently remains unclear whether older adults demonstrate any seasonal adaptations in their ability to dissipate over the course of a typical hot humid summer (e.g. Central Canada). Therefore, the purpose of this study was to examine the effects of aging on whole‐body heat loss and heat storage during an extreme heat exposure prior to (before June) and at the end of the summer (September). Five young (Young, age: 25 ± 3 years; body fat: 19 ± 6%) and five older (Older, age: 64 ± 7 years; body fat: 26 ± 9%) adults matched for body weight (Young: 82 ± 18 kg; Older: 86 ± 12 kg) and body surface area (Young: 1.9 ± 0.2 m2; Older: 2.0 ± 0.2 m2) rested for 3 hours in the heat (44°C, 30% RH). Whole‐body heat loss and metabolic heat production were measured continuously by direct and indirect calorimetry, respectively. Body heat storage was calculated as the temporal summation of heat production and heat loss. Our results show that the older adults had a reduced rate of whole‐body heat loss at the 1‐hour (Young: 105 ± 20 W vs. Older: 76 ± 12 W, p=0.021) and 2‐hour (Young: 115 ± 28 W vs. Older: 83 ± 11 W, p=0.048) time points prior to the start of summer relative to their younger counterparts. No differences were measured between age groups at the end of the 3‐hour heat exposure (p>0.05). As a result of the lower rate of heat loss, the older adults stored 1.3‐fold more heat than the young adults (170 ± 72 kJ, p=0.01). Following the summer period, no differences in the rate of whole‐body heat loss were measured between groups throughout the 3‐hour heat exposure. As a consequence, the change in body heat storage was similar between age groups (Young: 196 ± 113 kJ vs. Older: 226 ± 102 kJ, p=0.67), demonstrating that older adults were able to reduce the amount of heat stored within their body by 43% after 3 months of summer heat exposure in a humid continental climate. These results show that seasonal adaptations can improve whole‐body heat dissipation in older adults, thereby mitigating the age‐related impairments in the body's physiological capacity to dissipate heat during an extreme heat exposure.

Support or Funding Information

Funding support: This study was funded by the Canadian Institutes of Health Research (286363, grant held by Dr. Glen P. Kenny).
The effects of cold water immersion on inflammation, growth and neurotrophic factors in skeletal muscle after resistance exercise
Authors: Peake Jonathan , Roberts Llion , Raastad Truls , Figueiredo Vandre , Cameron‐Smith David , Coombes Jeff , Markworth James
Published: November 2023

Cold water immersion is often used to recover from exercise in the belief that it reduces muscle soreness and inflammation. However, no data currently exist to support this notion—at least in humans. We compared the effects of cold water immersion versus active recovery on neutrophil and macrophages, pro‐inflammatory cytokines, neurotrophic and growth factors, heat shock proteins and transcription factors in muscle after resistance exercise. In a randomized cross‐over design, 10 active men performed resistance exercise using one leg on separate days. On one day, they immersed their lower body in cold water (10°C) for 10 min after exercise. On the other day they cycled at a low‐intensity for 10 min after exercise. Muscle biopsies were collected from each leg before, 2, 24 and 48 h after exercise. Exercise induced a strong inflammatory response, as indicated by increases in neutrophil and macrophage counts and IL‐1β, TNF‐α, IL‐6 and MCP‐1 mRNA (P<0.05). Growth arrest and DNA damage‐inducible 45 protein (Gadd 45) mRNA also increased markedly (P<0.05). As evidence of hyperalgesia, nerve growth factor (NGF) and glial cell‐line derived neurotrophic factor (GDNF) mRNA increased after exercise (P<0.05). The protein abundance of Forkhead box class O (FOXO) and αB‐crystallin in the cytosolic fraction of muscle homogenates decreased after exercise (P<0.05), indicating nuclear translocation. Despite these robust responses, there were no significant differences in any of these factors between the two trials. Therefore, contrary to popular belief, cold water immersion did not attenuate inflammation or markers of soreness in muscle after intense resistance exercise.
Ablation of phosphatidylethanolamine methyltransferase promotes white adipose browning in mice
Authors: Strong Stephanie , Verkerke Anthony , Johnson Jordan , Wentzler Edward , Funai Katsuhiko
Published: November 2023

Obesity is caused by energy intake that chronically exceeds energy expenditure. Emerging evidence suggests that white adipose tissues can be reprogrammed to express mitochondrial uncoupling protein 1 (UCP1) to promote thermogenesis. This transformation, referred as “browning” of white adipose tissue, can increase energy expenditure and prevent obesity. Mice with a whole body knockout of phosphatidylethanolamine methyltransferase (PEMT) are protected from diet‐induced obesity due to an increase in whole‐body energy expenditure. However, the mechanism that promotes energy expenditure in these mice is unknown. We hypothesized that the absence of PEMT results in the browning of white adipose tissues. In this study, we examined adipose tissues from wild type (WT) and whole‐body PEMT knockout (PEMTKO) mice fed with a 10 week high‐fat diet. Inguinal and epididymal white adipose tissue (iWAT and eWAT) were analyzed for UCP1 expression by quantitative‐PCR, western blotting and immunohistochemistry. We found that mice lacking PEMT exhibited elevated RNA and protein abundance of UCP1 in iWAT and to a lesser extent in eWAT. These findings support our hypothesis that browning of white adipose tissue may contribute to increased energy expenditure in mice lacking PEMT. In future experiments, we will determine whether the absence of PEMT specifically in adipose tissues will promote browning and increased energy expenditure.

Support or Funding Information

This work was supported by NIH grant DK095774 to KF and APS/NHLBI STRIDE fellowship 1 R25 HL115473‐01 to SS.
Using AAV9 to trace bulbospinal inputs to phrenic motoneurons
Authors: Nair Jayakrishnan , Mandel Ronald J , Fuller David D
Published: November 2023

We used adeno associated virus (AAV) serotype 9 driving expression of green (AAV9‐cba‐GFP) or red (AAV9‐cba‐mCherry) fluorescent protein to examine the distribution of bulbospinal projections to the phrenic motor nucleus in the adult rat. Rats were anesthetized with isoflurane and focal injections of AAV9‐GFP (left medulla; titer: 1.19 × 10e13 vg/ml; volume: 0.25μl) and AAV9‐mCherry (right medulla; titer: 1.66 × 10e13 vg/ml; volume: 0.25μl) were targeted to the immediate region of medullary rostral ventral respiratory group (rVRG) as determined in separate neurophysiological recordings. In spinal intact rats, brainstem and spinal cord tissues were harvested 18‐wks following AAV injection. Separate animals received a cervical spinal cord hemisection injury (C2Hx) 4‐wks prior to the brainstem AAV injections. Phrenic motoneurons were retrogradely and bilaterally labeled 3‐days prior to tissue harvest using intrapleural delivery of cholera toxin‐beta (CT‐β, 0.2%, 5μl). When the rVRG showed robust transgene expression as indicated via fluorescence, a dense cluster of AAV9‐GFP or mCherry expressing terminal projections could also be observed in the phrenic nucleus bilaterally. In a few rats, injections were slightly lateral to the rVRG, and these produced minimal if any labeling in the region of the phrenic nucleus. Preliminary observation of medullary injected C2Hx cord (14‐wks) revealed robust AAV9‐GFP and mCherry expression in the phrenic nucleus contralateral to the lesion, and a dramatically reduced but even distribution of GFP and mCherry positive fibers along the ipsilateral phrenic nucleus. These initial results indicate that injection of AAV9 to the rVRG is an effective technique to label bulbospinal projections to the phrenic motor nucleus.

Support or Funding Information

1R01NS080180‐01A1 (DDF)
TrkB Agonist Treatment in Old Age Does Not Mitigate Diaphragm Neuromuscular Dysfunction and Sarcopenia
Authors: Vasdev Amrit Kaur , Greising Sarah M. , Sieck Gary C , Mantilla Carlos B
Published: November 2023

Neurotrophic signaling is essential to the maintenance of diaphragm muscle function across the lifespan. With aging, there is an age‐related loss of neurotrophic signaling and a resultant increase in diaphragm muscle denervation and impairment in neuromuscular transmission. We hypothesized that enhancing neurotrophic signaling via the tropomyosin‐related kinase receptor subtype B (TrkB) using the small molecule TrkB agonist 7,8‐dihydroxyflavone (7,8‐DHF) would mitigate age‐related changes in diaphragm neuromuscular transmission and possibly sarcopenia (muscle atrophy and force loss). Adult male TrkBF616A mice (n=32) were randomized to receive 6‐month oral treatment with vehicle (control), 7,8‐DHF, or co‐treatment with 7,8‐DHF and 1NMPP1(a specific inhibitor of TrkB kinase activity in TrkBF616A mice) beginning at 18 and ending at 24 months of age. Mice were analyzed for neuromuscular transmission failure using diaphragm muscle‐phrenic nerve preparations, diaphragm muscle force, and morphologic characteristics of sarcopenia. Chronic 7,8‐DHF treatment did not improve diaphragm neuromuscular function or force (P≥0.25). Co‐treatment with 7,8‐DHF and 1NMPP1 decreased the ratio of the initial nerve stimulation‐derived to initial muscle stimulation‐derived force (~22%) compared to vehicle (p=0.01), consistent with a deleterious effect of inhibiting TrkB kinase activity on aging diaphragm muscle. With age, there was fiber type specific atrophy of type IIa and type IIx and/or IIb diaphragm muscle fibers. There was no evidence of a protective effect of 7,8‐DHF on muscle fiber cross‐sectional area. Taken together, these results support a role for BDNF/TrkB signaling in old age but do not support 7,8‐DHF as a therapeutic agent to mitigate age‐related effects on diaphragm muscle function.

Support or Funding Information

Supported by R01‐AG044615, T32‐HL105355, and the Mayo Clinic.
Aging‐induced impairments in diaphragm isotonic contractile properties and modifications of proteomic and sphingolipid profile
Authors: Ferreira Leonardo F. , McDonagh Brian , Kelley Rachel C. , Coblentz Philip D. , Patel Nikhil
Published: November 2023

The diaphragm is involved in ventilatory and non‐ventilatory (e.g., sneezing and coughing) activities that are essential for gas exchange and airway clearance. Inspiratory efforts for sneezing and coughing, or breathing during exercise, require rapid shortening and powerful diaphragm contractions. Thus, impairments in diaphragm contractile properties compromise airway clearance and contribute to inability to sustain ventilation during physical activity. Aging causes diaphragm atrophy and loss of isometric specific force. However, the effects of aging on diaphragm isotonic contractile properties and muscular factors associated with dysfunction are not fully understood. Our goal in the current study was to determine diaphragm isometric and isotonic contractile properties and the associated changes in the proteomic and sphingolipidomic profile of the diaphragm in ‘very old’ age. We studied adult (6 months, n = 6) and very old mice (30 months, n = 6) obtained from the National Institute on Aging. We assessed contractile function in vitro (force‐frequency and force‐velocity protocols) and used mass spectrometry for global label free proteomics and sphingolipid analyses in diaphragm samples. Aging decreased maximal isometric specific force (N/cm2) by 20% (P < 0.01) and maximal shortening velocity (Lo/s) by 15% (P = 0.098). We calculated power as force × velocity and determined that aging caused a 35% loss in peak power (W/kg) (P < 0.01). Our initial proteomic analysis revealed down regulation of glycolytic enzymes and calcium regulatory proteins, while cytoskeletal proteins were upregulated in diaphragm of old mice (P<0.01, false‐discovery rate 1%). Our sphingolipid analysis showed increases in diaphragm sphingosine‐1‐phosphate content (P<0.05) with no changes in ceramide levels. Overall, our findings suggest pronounced impairments in diaphragm isotonic contractile properties in the elderly. The disruption of the metabolic machinery and calcium regulation are putative factors causing abnormal diaphragm function with aging.

Support or Funding Information

R03‐AG040400‐02
DHA is more potent than EPA in attenuating cardiometabolic risk in men and women: a randomized double‐blind, placebo‐controlled crossover trial
Authors: Allaire Janie , Couture Patrick , Charest Amélie , Leclerc Myriam , Marin Johanne , Lépine Marie‐Claude , Tchernof André , Lamarche Benoît
Published: November 2023

Background

Most studies to date on the cardiometabolic effects of eicosapentaenoic (EPA) and docosahexaenoic (DHA) in humans have used a mixture of the two fatty acids in different forms and proportions. The objective of this study was to compare the individual effects of EPA vs. DHA supplementation (as re‐esterified triacylglycerol, 90% pure) on blood lipids and inflammatory markers in men and women at risk of cardiovascular diseases.

Methods

Using a double‐blind, placebo‐controlled crossover design, 48 men and 106 women with abdominal obesity were randomized to three treatment phases: 1‐EPA (3g/d), 2‐DHA (3g/d), 3‐corn oil (placebo, 3g/d). Treatments had durations of 10 weeks each and were separated by an 8‐week washout period. Blood lipids and inflammatory markers were measured before and after each treatment phase. Differences in study outcomes between treatments were assessed using the MIXED procedure for repeated measures with endpoint measures as primary outcomes. Potential confounders of the response to treatment, mainly obesity/body fat status, age, use of contraceptive agents (premenopausal women), menopausal status, treatment‐specific baseline values and sequence of treatments were considered.

Results

EPA vs. placebo decreased plasma TG concentrations (−11.1±2.4%, p<0.001). DHA vs. placebo decreased diastolic blood pressure (DBP, −2.2±0.9%, p<0.001), TG (−18.1±2.5%, p<0.001), cholesterol(C)/HDL‐C ratio (−2.5±1.4%, p=0.02), CRP (−8.4±5.0%, p=0.03), TNF‐α (−13.7±5.2%, p=0.02) and IL‐18 (−4.8±2.9%, p=0.01), and increased total C (+2.5±1.2%, p=0.001), HDL‐C (+6.1±1.2%, p<0.001) and LDL‐C (+5.0±1.9%, p<0.001). Changes in DBP (p=0.03), TG (p=0.02), total C (p<0.001), HDL‐C (p<0.001), LDL‐C (p=0.03), C/HDL‐C ratio (p=0.02), IL‐18 (p=0.007) and adiponectin (p<0.001) were greater with DHA than with EPA.

Conclusion

DHA is more effective than EPA in modulating blood lipids and inflammatory markers. Further studies are needed to determine the impact of a long term DHA supplementation on cardiovascular risk in men and women.

Support or Funding Information

This research was funded by the Instituts de recherche en santé du Canada (IRSC/CIHR). Janie Allaire is recipient of a scholarship from the Fonds de Recherche du Québec – Santé (FRQ‐S) for graduated students with a Professional Degree.
Managing the Growing Classroom: Opportunities for Postdoctoral Teaching Fellows
Authors: Nevins Julie E.H. , Wilkinson Amanda L.
Published: November 2023

Increasing undergraduate class sizes place high demands on professors in the field of nutrition. Postdoctoral teaching fellows can absorb some of the teaching workload and elevate the quality of undergraduate education. These positions are mutually beneficial to professors, undergraduate and graduate students, and postdoctoral scholars.

Teaching fellows advance undergraduate learning by promoting evidence‐based teaching practices, as well as innovative and engaging learning activities. Further, undergraduates gain the opportunity to interact with an additional doctoral‐level scientist in the field of nutrition. Graduate and undergraduate teaching assistants benefit from direct mentoring from both professors and postdoctoral teaching fellows. This mentorship can enhance the larger teaching and learning environment to improve the educational experience in courses across the department.

The teaching‐oriented fellowship provides postdoctoral scholars with experiential training in effective undergraduate education within their discipline, a skill‐set that is not often developed in a traditional postdoctoral position. The professor serves as a mentor, role model, and collaborator in both teaching and research to the teaching fellow. As a nutrition scientist, the teaching fellow can manage day‐to‐day activities and teaching personnel, help link research to the classroom, and serve as an intermediary between professor and students.

We will discuss our experiences as teaching fellows including the benefits and challenges of the position, the projects we have contributed to, and ideas for the future. We provide examples of evidence‐based teaching that we have incorporated into the classroom, and will also share perspectives from undergraduates in the courses we support.

Postdoctoral teaching fellowships can address the increased teaching demands due to larger class sizes, and heighten the quality of undergraduate nutrition education. These positions are advantageous for professors, students, and postdoctoral scholars alike.
Novel Tool for Discrimination of Feeding Intolerance and Necrotizing Enterocolitis Risk in the Preterm Infant
Authors: Naberhuis Jane , Wetzel Chris , Tappenden Kelly
Published: November 2023

Background

Preterm infants are at increased risk of developing feeding intolerance and necrotizing enterocolitis (NEC). Comprehensive nursing assessments can improve infant outcomes through early identification of these conditions.

Objective

To validate a novel nursing tool for assessment of neonatal feeding intolerance and NEC risk.

Methods

The tool was developed based on published literature and implemented in a University of Illinois‐affiliated 48‐ bed level III neonatal intensive care unit following Institutional Review Board approval. Data were collected from the electronic medical record of all preterm infants with parental consent during the study period. Tool error rate, consistency (Cronbach's alpha), and inter‐rater reliability (intraclass correlation coefficient [ICC] and Fleiss’ kappa) were assessed. Risk factors significant to the development of feeding intolerance (days with emesis, abdominal distention, or gastric residuals > 50% of previous feeding volume) and NEC (ICD‐9 557.0, 777.50, 777.51, 777.52, or 777.53) were identified through χ2 testing. Tool discrimination was evaluated via receiver operating characteristic (ROC) curve. Pearson correlation coefficient and independent t‐test were used to assess construct validity. Following these assessments, the tool was optimized and reassessed. Optimization was achieved by removing factors not significant to ≥ 2 outcomes of interest and weighting point values assigned to each factor.

Results

From August 2013 to December 2014, 49 nurses scored 499 tools on the 133 enrolled infants. Cronbach's alpha (0.71), ICC (0.99), and Fleiss’ kappa (1.00) were in acceptable ranges. Scoring error rate was 9.2%, and inversely related to the number of tools a given nurse scored (R2 = 0.53, P = 0.01). Total optimized tool score was associated with all outcome measures (area under the ROC curve; diagnostic odds ratio [95% CI]) for the number of days with emesis (0.67; 1.12 [1.05, 1.21]), abdominal distention (0.81; 1.27 [1.17, 1.41]), or gastric residuals > 50% of previous feeding volume (0.62; 1.10 [1.03, 1.18]), and NEC (0.91; 1.30 [1.13, 1.59]). Correlation coefficients for each of these outcomes were 0.50, 0.60, 0.49, and 0.36, respectively. Optimized tool scores of infants who did and did not develop each of the outcome measures were significantly different (P < 0.05).

Conclusions

The tool is a clinically efficacious means to discriminate infants at risk of feeding intolerance and NEC. Implementation at additional institutions and further refinement will improve its clinical utility.

Support or Funding Information

Internally funded.
Emphasizing the Importance of Qualitative Research in Anatomy Education: A “How‐to‐Guide” on Case Study Design, Implementation, and Data Analysis
Authors: Traser Courtney J.
Published: November 2023

In a scientific domain brimming with grant‐funded biomedical research and a heavy emphasis on the scientific method, qualitative anatomy education research is frequently and lamentably over‐shadowed. The establishment of Anatomical Sciences Education has markedly increased both the quality and quantity of anatomy education research; however, the overwhelming majority of published anatomical research projects are quantitative in nature or, at most, utilize a mixture of both quantitative and qualitative techniques. Although still regarded as “inferior” by many basic scientists, the purposeful inclusion of purely qualitative research projects into the anatomical education discipline would provide researchers with rich insights not easily gained through quantitative or even mixed methods designs. Accordingly, this project serves as both an introduction to and a “how‐to‐guide” for conducting a qualitative case study, a type of qualitative methodology well‐suited for anatomy education. By definition, a qualitative case study uses observations, interviews, and document analyses to investigate a specific event or phenomenon (e.g., a person, class, process, or institution) and results in the production of a rich, descriptive interpretation of the studied event. A broad overview of the types of qualitative case studies will be presented, along with insights into study design, data collection, and analysis of results. An example of a qualitative case study that examined the perceptions of anatomy faculty members at both an allopathic and osteopathic institution will be used to highlight the research process and to demonstrate how the findings of such research can be communicated.
Aortic Depressor Nerve Morphology in Developing Spontaneously Hypertenvie Rats
Authors: Amorim Milena Menezes , Castania Jaci A , Salgado Helio Cesar , Fazan Valeria Paula Sassoli
Published: November 2023

Aortic Depressor Nerve (ADN) is an aferent nerve that originates on the aortic arch. Its major function is providing constant information about the body hemodynamics (beat by beat) to the Central Nervous System (NCS) in order to maintain cardiovascular homeostasis. This nerve is constituted by myelinated fibers (A‐type) and unmyelinated fibers (C‐type). In this study, we analyzed the myelinated fiber's morphology and morphometry in Spotaneously hypertensive rats (SHR) in different ages. We used SHR at 5 weeks (8 female, 5 male), 20 weeks (5 female, 8 male), 50 weeks (8 female, 9 male) of age and normotensive controls Wistar Kyoto rats (WKY) 20 weeks‐old (7 female, 6 male). All animals had their left ADN recorded for spontaneous activity associated with the arterial pressure pulse. After the electroneurographic recordings, proximal (close to nodose ganglion) and distal (at clavicle level) segments were prepared for epoxy resin embedding. Semithin cross sections of ADN segments were stained with 1% toluidine blue and analyzed by light microscopy. The morphometric study of the myelinated fibers was performed with the aid of computer software and took into consideration the myelinated fiber and respective axons area, diameter and the G ratio (axon diameter/fiber diameter). Comparison between proximal and distal segments made for the same strain, gender and age showed no morphometric differences. At 20 weeks of age, male WKY presented significantly larger number of fibers than male SHR, while comparisons between females showed no significant differences. The aging SHR morphometric data indicated that the nerve growth stopped at 20 weeks of age in both genders, suggesting that the 5 week old animals myelinated fibers are not fully developed for the best conduction velocity. Also, in elderly male SHR, the reduction of G ratio points to an axonal atrophy, that could explain, at least in part, the fact that males have higher blood pressure than females.

Support or Funding Information

FAPESP, CNPq, CAPES and FAEPA
Molecular asymmetries in actin dynamics drive left‐right organogenesis
Authors: Trinh Le A. , Koo Eun , Trivedi Vikas , Bagnat Michel , Fraser Scott E.
Published: November 2023

The embryonic heart tube arises from bilaterally symmetric populations of cells in the anterior lateral plate mesoderm (LPM). These bilateral progenitors undergo epithelial maturation and migrate as coherent sheets of cells that fuse at the midline to form the linear heart tube, which exhibit left‐right asymmetry. Here, we explore the dynamics of the actin cytoskeleton in coordinating the morphogenesis of the LPM during heart tube formation in zebrafish using a fluorescent reporter of actin dynamics, LifeAct‐GFP. Multiphoton time‐lapse microscopy coupled with quantitative analysis of 4‐dimensional data (x,y,z,t) reveal a number of dynamics in actin polymerization within the LPM that is suggestive of differential force exertion from the LPM cells as they undergo morphogenesis. These actin dynamics are asymmetrically distributed and are dependent on both Nodal signaling and tissue‐tissue interaction. The asymmetries can be uncoupled genetically and are required for leftward placement of the heart tube. Taken together, these data suggest that the LPM exerts multiple cellular traction forces as it undergoes midline migration and morphogenesis to form a leftward positioned linear heart tube.
Non‐invasive evaluation of anomalous aortic origin of coronary arteries and surgical management
Authors: Ashwath Ravi , Prasad Deepa
Published: November 2023

Advances in imaging of the coronary arteries allow more detailed and accurate information to be assessed to detect anomalies that might prevent a young athlete dying on the field. Normal coronary anatomy includes origin of left coronary artery from left sinus of Valsava, which then divides into left anterior descending artery and left circumflex coronary artery and origin of right coronary artery from the right sinus. Anomalous aortic origin of coronary arteries (AAOCA) is when the coronary arteries arise from opposite sinus or wrong sinus or as single right or left coronary artery. AAOCA is rare with an incidence of about 0.2%. However, it is the second most common cause of sudden cardiac death in young athletes.

Most patients are asymptomatic and sudden death could be the initial presentation, which is provoked by myocardial ischemia leading to myocardial infarction and lethal arrhythmia's. The pathological mechanisms attributed to the coronary compression include, intramural/interarterial course, slit‐like orifice, acute angle take‐off, hypoplastic coronary arteries and coronary artery dominance. Anomalous left coronary artery from right sinus is thought to carry a higher risk of sudden death than anomalous right coronary artery.

Echocardiography is a useful tool in the initial evaluation of AAOCA but generally needs to be complemented and confirmed by advanced imaging such as computed tomographic angiography (CTA) or magnetic resonance imaging (MRI). The intramural and interarterial course can be easily determined by CTA and in most cases by MRI. A slit like orifice can be visualized by CTA, however with technological advancements in CT, it is possible to obtain dynamic images of the coronary artery origin, which has enabled us to determine the slit like orifice more accurately. MRI has enabled us to identify myocardial viability by using stress perfusion and late Gadolinium enhancement imaging.

Accurate delineation of the coronary anatomy and viability is important in the decision making for management and pre‐operative evaluation. There are various surgical options depending on the type of coronary anomaly and presence of additional risk factors.

Support or Funding Information

Deepa Prasad M.D. is funded by AAA
Imaging the Role of Macrophage in Infection and Sterile Injury in Liver
Authors: Kubes Paul , Zeng Zhutian , Jenne Craig
Published: November 2023

In the liver, populations of resident macrophage and recruited monocytes play key roles in both the clearance of infection and tissue repair.

Kupffer cells are liver macrophage that reside directly within the bloodstream, adherent to the sinusoid walls, ideally positioned to detect and capture pathogens. Using intravital microscopy (IVM), we are able to directly visualize Kupffer cells in the liver of live mice and to study how these cells bind, and clear bacteria from the bloodstream. IVM has revealed a number of unique aspects of pathogen recognition including antibody‐dependent, complement‐dependent and antibody/complement‐independent mechanisms of pathogen capture. The specific mechanism used by the Kupffer cell appears to vary according to the pathogen involved and these findings provide great insight into the development of vaccination strategies and new antibody‐based therapies designed to target specific pathogens.

In contrast to infectious disease, tissue repair following sterile injury in the liver does not depend on the resident Kupffer cells, but rather, is dependent on the recruitment of inflammatory monocytes. Using IVM and mice with fluorescent reporter genes for various monocyte populations, we have identified that these recruited monocytes clear cellular debris from the site of injury and then transition, in situ, from classic CCR2high (Cx3CR1low) monocytes to reparative Cx3CR1high (CCR2low) alternative monocytes that support tissue repair and wound healing. This transition of CCR2high cells to Cx3CR1high monocytes is driven by the presence specific cytokines including IL‐4 and IL‐10. Failure to recruit to the initial CCR2high cells or inhibition of the CCR2high to Cx3CR1high phenotype transition results in abnormal tissue repair including defects in collagen deposition and delayed wound healing.
Illuminating biology at the nanoscale with single‐molecule and super‐resolution imaging
Authors: Zhuang Xiaowei
Published: November 2023

Dissecting the inner workings of a cell requires imaging methods with molecular specificity, molecular‐scale resolution, and dynamic imaging capability such that molecular interactions inside the cell can be directly visualized. Fluorescence microscopy is a powerful imaging modality for investigating biological systems largely owning to its molecular specificity and dynamic imaging capability. However, the diffraction‐limited resolution of light microscopy is substantially larger than molecular length scales in cells, making many sub‐cellular structures difficult to resolve. We developed a super‐resolution fluorescence microscopy method, stochastic optical reconstruction microscopy (STORM), which overcomes the diffraction limit by using photo‐switchable fluorescent probes to temporally separate the spatially overlapping images of individual molecules. This approach has allowed multicolor and three‐dimensional imaging of living cells with nanometer‐scale resolution and enabled discoveries of novel sub‐cellular structures. In this talk, I will discuss the technological advances and applications of STORM, with the focus on the recent biological discoveries enabled by STORM.

I will also describe a recently developed single‐cell transcriptome imaging method. In situ transcriptomic analyses of single cells promise to transform our understanding in many areas of biology, such as the mechanism of gene regulation, the heterogeneous behavior of cells, and the development and maintenance of cell fate. Single‐molecule imaging allows for counting and mapping of RNA molecules in individual cells; however, the number of RNA species that can be simultaneously imaged has been limited. To overcome this challenge, we developed a new imaging approach, multiplexed error‐robust fluorescent in situ hybridization (MERFISH), which allows numerous RNA species to be quantified in a spatially resolved manner in single cells in situ. This approach enables unique analyses based on the variation and correlation of copy numbers and spatial distributions of many RNA species within single cells, facilitating the delineation of gene regulatory networks and in situ identification of cell types. In this talk, I will also discuss the technology development and applications of MERFISH.
Quality Control Of Nuclear Pore Complex Biogenesis
Authors: Lusk Patrick , Webster Brant , Jaeger Jens , Thaller David
Published: November 2023

Nuclear pore complexes (NPCs) are massive protein assemblies that are inserted into the nuclear envelope and control the bidirectional exchange of molecules between the nucleus and cytoplasm. Each NPC is made up of ~30 proteins termed nups, which are found in multiple copies such that hundreds of nups ultimately build an individual NPC. Understanding the molecular mechanisms that underlie the spatial and temporal assembly of NPCs remains a central challenge in the field, particularly during interphase when NPC assembly occurs into intact nuclear membranes. Moreover, given that a single defective NPC could compromise the barrier function of the nuclear envelope, it is essential to understand how NPC quality is ensured and whether there are mechanisms capable of recognizing and removing defective NPCs. Consistent with this idea, our recent work showed that the endosomal sorting complexes required for transport (ESCRT) machinery helps ensure the formation of functional NPCs in budding yeast. Moreover, we identified the storage of improperly assembled NPCs compartment (SINC) that sequesters defective NPCs in mother cells to prevent their inheritance by progeny. We continue to investigate the mechanism by which the ESCRTs contribute to NPC quality control and are investigating the physical interactions between ESCRT‐III, nucleoporins and the Lap2‐emerin‐MAN1 (LEM) domain containing integral inner nuclear membrane proteins, Heh1 and Heh2, using several in vivo and in vitro approaches. We have also tested interactions with the mammalian orthologue of the ESCRT‐III‐like protein, CHMP7, which was recently implicated in recruiting ESCRT‐III to the nuclear envelope in a mammalian tissue culture model. Our data are consistent with the interpretation that Heh1 recruits the CHMP7 orthologue to the nuclear envelope during nuclear pore biogenesis.

Support or Funding Information

NIH GM105672