bluuebunny/crossref_metadata_2025 huggingface dataset:
Insulin Increases Respiration Rate in Healthy Young Men
Authors: Barbosa Thales C , Holwerda Seth W , Young Colin N , Thyfault John P , Fadel Paul J
Published: November 2023

Previous in vitro and in vivo studies in rats have indicated that carotid body chemoreceptors are capable of increasing respiration in response to acute hyperinsulinemia. Although increased respiratory rate has also been detected in humans during insulin infusion, it was accompanied by hypoglycemia, which is known to independently stimulate carotid chemoreceptors. Therefore, a hyperinsulinemic euglycemic clamp was performed to test the effect of elevated insulin on respiration rate, while glucose was maintained constant. We tested the hypothesis that elevated plasma insulin would increase respiration rate. Seventeen healthy young men [27 ± 1 years; 25.5 ± 0.7 kg m−2 (mean ± SEM)] received a venous infusion of insulin (30 – 40 mIU m−2 min−1) for 120 min while glucose was maintained at euglycemic concentrations throughout via a variable 20% dextrose infusion. Plasma glucose was determined every 5 min to adjust the dextrose infusion. In addition, every 30 min blood samples were taken and stored for later determination of insulin and glucose levels; and respiratory rate was determined from the abdominal movements detected with a strain‐gauge pneumobelt. As expected, insulin concentrations were elevated and maintained throughout the clamp (Baseline: 5 ± 1 μIU mL−1, Clamp at 120 min: 42 ± 5 μIU mL−1; P < 0.01), while glucose remained at fasting values (Baseline: 89 ± 2 mg dL−1, Clamp at 120 min: 83 ± 2 mg dL−1; P = 0.15). Respiration rate increased at 30 min following insulin infusion (Baseline: 13.8 ± 0.7 breaths min−1, Clamp at 30 min: 14.9 ± 0.7 breaths min−1; P < 0.01) and this elevation was maintained throughout the clamp reaching a peak value of 15.9 ± 0.6 breaths min−1 (P < 0.01). In a subset of subjects, respiration rate remained unchanged during saline infusion (Baseline: 14.3 ± 0.3 breaths min−1, Clamp at 120 min: 14.9 ± 0.2 breaths min−1; P = 0.41). These preliminary findings suggest an excitatory effect of insulin to increase respiratory rate in healthy humans.

Support or Funding Information

Funding Source: AHA Grant In Aid 20160072
Orexin A receptor 1 (OX1R) activation increases CamK2 expression in PC12 cells
Authors: Fan Yuanyuan , Jiang Enshe , Chen Qinchui , Shan Zhiying
Published: November 2023

Previous study have demonstrated that orexin receptor activation resulted in an increase in sympathetic activity and elevation in intracellular calcium levels. This observation coupled with the important role of calcium on the control of Ca2+/calmodulin‐dependent protein kinase II (CamK2) activity have led us to hypothesize that orexin system may involve in increasing sympathetic nerve activity through stimulating the expression of CamK2. In this study, we test this hypothesis using the neuron‐like PC12 cell which artificially expressing human orexin A receptor 1 (OX1R). Consistent with previous finding, incubation of human orexin A (100 nM) dramatically increased the cytosolic calcium level measured with a fluorescent calcium probe (Fluo‐4AM) in PC12‐OX1R cells. In addition, orexin A treatment (100nM) for 6 hours resulted in significant increases in the mRNA levels of calcium dependent protein early growth response 1 (EGR1, 25‐fold, P<0.05), CamK2a (2‐fold, P<0.05), CamK2b (4‐fold, P<0.05) as well as Fosl1 (9‐fold, P<0.05), a chronic neuronal activation marker, compared to control group. These data suggest that binding of orexin A and OX1R increases calcium influx which may subsequently stimulates EGR1 expression, the EGR1, as a major transcription regulator, may modulate expression of many genes including the expression of CamK2, which eventually increase neural firing. Our further study will investigate whether or not blockage of CamK2 will attenuate the increase in sympathetic nerve activity.

Support or Funding Information

NIH R15HL129213 (Shan)
Slicing Orexin Receptor 1 in Paraventricular Nucleus Decreased Hypertension in Obesity Zucker Rats
Authors: Zhou Jing‐Jing , Zhang Yi , Li De‐Pei
Published: November 2023

Orexin has been reported to involve in pathogenesis of obesity‐related hypertension. We found recently that that upregulation of orexin receptor 1 (OXR1) contributed to sympathetic overflow through excitation of presympathetic neurons in paraventricular nucleus of hypothalamus. The present study aimed to slicing OXR1 in PVN of Obese Zucker Rats (OZRs) to normalize the hypertensive status in OZRs. Blood pressure was monitored in free‐moving OZRs through implantable telemetry system. AAV‐OXR1‐shRNA and scrambled shRNA were constructed and bilaterally microinjected into the PVN. AAV‐OXR1‐shRNA significantly downregulation expression levels of OXR1 in the PVN tissue in OZRs, whereas orexin receptor 2 (OXR2) expression levels were not significantly changed. In addition, the retrograde labeled spinally projecting PVN neurons displayed significantly reduced OX1R immunostaining signals. The mean arterial blood pressure decreased by AAV‐OXR1‐shRNA treatment for 4–6 weeks, which companied with a lowered heart rate (HR). Spectral analysis of pulse‐pulse intervals revealed that low frequency to high frequency (LF/HF) ratio was significantly decreased. Furthermore, slicing OXR1 in PVN by AAV‐OXR1‐shRNA eliminated orexin‐induced increases in blood pressure and sympathetic activity in OZRs. In addition, the hyperactivity of spinally projecting PVN neurons in the OZRs was significantly decreased by AAV‐OXR1‐shRNA treatment. Taking together, these findings suggest that slicing OXR1 in PVN effectively normalizes elevated sympathetic vasomotor tone in obesity‐related hypertension.

Support or Funding Information

This work was supported by the National Institutes of Health (Grants MH096086 to D‐P. L.), National Natural Science Foundation of China (31271223 and 31071002), National Basic Research Development Program of China (2012CB518200), and the Natural Science Foundation of Hebei Province (C2012206001).
Effect of a Pre‐Dinner Snack on Buffet Meal Caloric Consumption in College Freshman
Authors: Schmitz Sophie A , Sebranek Phoebe L , Kern Shelby E , Hoppe Megan B , Scott Hattie J , Eastep Ashley C , Horwath Irina E , Wilson Ted
Published: November 2023

Post adolescent weight gain is a concern among college freshman, especially those enrolled in cafeteria meal plans. Snack consumption prior to a meal could alter feeding behavior during the meal. Healthy college students (n=57; age 18.3±0.1) received one of three treatments 60 minute before choosing and eating a cafeteria dinner meal (no snack (NS; control), 190 Cal of gummi bear candy (GB), or a 190 Cal serving of California walnuts (CW) 60 minutes prior to dinner in single cross‐over fashion on 3 of 5 semi‐consecutive nights. Meal images before and after consumption were used for nutritional analysis and the determination of the calories that were consumed and unconsumed (left over on tray) at the end of the meal. This study highlights the complex interaction between pre‐dinner snack choice and food consumption during a meal in a homogeneous college population. Understanding how nut consumption influences this feeding pattern could help clinicians improve dietary health.

Support or Funding Information

California Walnut Commission
Dihydroxyacetone phosphate (DHAP) induced type‐I collagen glycation and the formation of cross‐linked advanced glycation end‐products (AGEs) in vitro
Authors: Liu Weixi , Dombi George W , Dain Joel A
Published: November 2023

Collagen glycation by glucose is implicated in the pathology of diabetes because elevated glucose level can interfere with collagen cross‐linking causing the loss of its structural order. However, there is lack of data on collagen glycation by other sugar metabolites whose levels are also increased in diabetes mellitus. We studied the glycation of type‐I collagen with dihydroxyacetone phosphate (DHAP), a triose sugar generated in many metabolic pathways including glycolysis. An in vitro reaction model with bovine type‐I collagen was developed to evaluate the impact of DHAP glycation on collagen structure and functions. During a 30‐day incubation period at 37°C, the free lysine residues of collagen started to decrease shortly after the reaction started (1‐day), indicating the attachment of DHAP molecules onto the ɛ‐amino groups of lysine. After 7 days, fluorescent glycation products were gradually generated as characterized by fluorescence spectroscopy. These products were then confirmed by ELISA to be pentosidine, a cross‐lined fluorescent compound that serves as a reliable biomarker for advanced glycation end‐products (AGEs). Compared to non‐glycated native collagen, the fibril formation of glycated collagen was significantly delayed at early glycation and completely halted at late stage of the reaction. Since collagen fibril formation is critical for wound healing, the data suggested that DHAP can disturb such process by inducing collagen glycation and can play a role in delaying wound healing in diabetes.
The effects of acetate on enhancing the proliferation and preadipocyte differentiation of stromal vascular cells isolated from Hanwoo beef cattle
Authors: Baatar Delgerzul , Wandita Theresia Galuh , dela Cruz Joseph Flores , Hwang Seong Gu
Published: November 2023

We investigated the effect of acetate on the proliferation and differentiation of bovine stromal‐vascular cells (SVC). SVC was isolated from the longissimus muscle collected directly from approximately 30‐month‐old Hanwoo beef cattle steers. After confluence, the differentiation was induced by 1‐methyl‐3‐isobutyl‐xanthine, dexamethasone, insulin, and rosiglitaszone for 2 days, and then subsequently cultured for 14 days. The cells were treated with different concentrations of acetate (0.125 to 2 mMol) throughout the differentiation period. Cell viability assay revealed a dose‐dependent increase in the proliferation of SVC. Monitoring of the differentiation through Oil Red‐O staining showed that treatment with acetate up to 1mMol significantly increased cell differentiation and fat accumulation. Supplementation of acetate in the media throughout the differentiation period also enhanced the induction of all differentiation markers. Acetate treatment unregulated the mRNA and protein expression of peroxisome proliferator‐activated receptor gamma (PPARγ), CCAAT/enhancer binding protein alpha (C/EBPα), Sterol regulatory element‐binding protein 1c (SREBP‐1c), fatty acid binding protein 4 (FABP 4) and fatty acid synthase (FAS). These data suggests that acetate can enhance adipocyte differentiation from SVC isolated from Hanwoo beef cattle and possibly improve meat palatability through increased intramuscular fat deposition and reduce meat toughness through decreased fibrogenic differentiation.

Support or Funding Information

This work was carried out by the support of the Rural Development Administration Grant (Project No. PJ01268703).
Evaluation of Patient‐Specific MTERF4 Variants in Gene‐Edited Human iPSC‐derived Cardiomyocytes
Authors: Marquez Maribel , McDermott‐Roe Chris , Grysbowski Michael , Helbling Daniel , Dimmock David P. , Verbsky James W. , Geurts Aron M
Published: November 2023

Mitochondrial Transcription Termination Factor 4 (MTERF4) has been well established as a transcription factor for mitochondrial ribosomal biogenesis and was identified as a gene of interest via exome sequencing in a male 6‐year‐old patient with hypertrophic cardiomyopathy (HCM) at Children's Hospital of Wisconsin. This patient's specific variant in MTERF4 has not been previously reported in the literature or associated to HCM. An existing mouse model by Cámara et al. has shown that a global knock out (KO) of MTERF4 resulted in embryonic lethality at developmental stage E8.5 and that a heart‐specific conditional KO resulted in an enlarged heart. Our lab has combined precision genome editing via CRISPR/Cas9 system with human iPSC‐derived cardiomyocytes (CMs) to model this patient‐specific MTERF4 variant to determine if it is responsible, or contributes to, the patient's HCM phenotype. Due to low homology‐directed repair (HDR) events in human iPSCs, we employed a novel co‐targeting selection method that enhances targeting efficiency. Based on the previously published literature of MTERF4 knock outs, we hypothesize that our MTERF4 mutant clones, once differentiated into cardiomyocytes, will be larger in size and have an increased transcriptional expression of HCM markers as well as an increase in mitochondrial transcript and protein expression. Three mutant MTERF4 clones have been identified by sanger sequencing, were assessed for pluripotency using immunostaining for SSEA‐4 and Oct4, and QPCR was done using Oct4, GATA4, and SOX2 primers. Human iPSCs that have undergone our targeting protocol and were negative for the MTERF4 variant will serve as controls for the MTERF4 mutant clones. MTERF4 clones and controls will be subjected to our modified Palecek matrix‐overlay method for cardiomyocyte differentiation, at 3–4 weeks CMs will be assessed for cell size using immunostaining for Cardiac Troponin T, the transcriptional expression will be done via QPCR, and mitochondrial protein expression assessed by western blot. Future mechanistic studies will be driven by the correlation between MTERF4 variant and HCM.

Support or Funding Information

Keck foundation and NIH Director's New Innovator award (DP2‐OD08396)
Hypercapnia Upregulates Expression of the NH3/NH4+ Transporter Rhbg in the Kidney
Authors: Nakhoul Nazih L , Hering‐Smith Kathleen , Hamm L. Lee , Islam M. Toriqul , Abdulnour‐Nakhoul Solange
Published: November 2023

Hypercapnia occurs in patients with acute and chronic lung diseases such as chronic obstructive pulmonary disease (COPD) and acute respiratory distress syndrome and is a major cause of increased mortality in hospitalized sick patients with COPD or cystic fibrosis. The kidneys compensate for respiratory acidosis by increasing urinary acid excretion (predominantly as NH3/NH4+) and de‐novo production of HCO3−. The mechanisms responsible for increased renal NH3/NH4+ excretion are not well known. In this study, we investigated whether the renal NH3/NH4+ transporters, Rhbg and Rhcg, are affected by hypercapnia. Using H+‐selective microelectrodes, we showed that CO2 caused a faster intracellular pH (pHi) decrease in oocytes expressing Rhbg as compared to H2O‐injected oocytes (−47 vs −17 × 10−4 pH/sec) indicating enhanced CO2 transport by Rhbg. Using In‐Cell Western, we showed that inner medullary collecting duct IMCD3 cells (that express Rhbg and Rhcg) grown on semi‐permeable membranes had a dramatic increase in Rhbg expression after 48 hours exposure to 20% CO2. Rhcg expression followed a similar pattern but the proportional increase in expression was smaller. In a series of in‐vivo experiments in mice, we induced respiratory acidosis by placing the mice in special chambers where the breathing gas mixtures were 8% CO2 (balance 21% O2 & 71% N2). Control group breathed normal air. After 4 days, the kidneys were extracted and Rhbg protein expression was assessed by Western analysis. Our data indicate that in hypercapnia Rhbg expression was increased by 23%, compared to control (n=5, p<0.05). These results indicate that CO2 is transported by Rhbg and that respiratory acidosis upregulated Rhbg expression. Enhanced cellular CO2 transport, due to elevated CO2 in respiratory acidosis and/or changes in acid‐base status, may be responsible for upregulating expression of the renal NH3/NH4+ transporter Rhbg.

Support or Funding Information

VA Merit grant, NIH‐RO1 and Tulane Institutional Fund
Human peptidylarginine deiminase types 2 and 4 target glycine‐containing motifs for citrullination: An in silico study
Authors: Olson Justin Scott , Meyer Dylan , Grant Jennifer
Published: November 2023

The human peptidyl arginine deiminases (hPAD), a family of five calcium‐dependent enzymes, facilitates the post‐translational modification, citrullination. The isozymes hPAD2 and hPAD4 are of particular importance, as they appear to play a role in the development and progression of several autoimmune diseases. To better characterize primary and secondary structure determinants of citrullination, we mined protein sequences known to contain arginine residues susceptible to citrullination by hPAD2 or hPAD4 from the literature, generating protein secondary structure predictions using PSIPRED prediction software. Of the citrullinated sequences identified, 70% of citrullinated arginine for hPAD2 and 81% of citrullinated arginine for hPAD4 were predicted to reside within a disordered secondary structure. The motif extracting software Motif‐X was used to elucidate statistically significant motifs within the general peptide data sets and within a data set of peptides belonging to disordered secondary structure conformations. Both hPAD2 and hPAD4 appear to favor citrullination of motifs containing arginine neighbored by glycine at the +1 and/or +2 position, and hPAD4 favors glycine the +3 position, relative to the target arginine.
The Local Vascular Activity of Norepinephrine (NE) in Renal Perivascular Adipose Tissue (PVAT)
Authors: Restini Carolina Baraldi A. , Burnett Robert , Fink Gregory D. , Watts Stephanie W.
Published: November 2023

Perivascular adipose tissue (PVAT) is implicated in the pathophysiology of cardiovascular disease, especially in obese individuals in which the quantity of PVAT is markedly increased. We have shown previously that PVAT around the aorta and mesenteric arteries contains releasable norepinephrine (NE) that can constrict the underlying arteries. Although obesity in known to be especially associated with increased noradrenergic activity to the kidneys, and PVAT is found adjacent to the main renal arteries and their primary branches, it is not known if NE derived from PVAT affects the tone of the renal vessels. Therefore, in this study we tested the hypothesis that PVAT around the main kidney artery contains sufficient releasable NE to cause arterial contraction. Tissue NE concentration was measured by High Performance Liquid Chromatography (HPLC). Isometric vascular contractility studies were performed using endothelium intact rings (2 mm) from the main renal artery of normal male Sprague‐Dawley rats. Some rings were studied with PVAT still attached (+PVAT), while others had PVAT removed (−PVAT). Tyramine (Tyr), an indirectly acting sympathomimetic, was used to test for the presence of a functional NE pool in PVAT. Tyr concentration‐response curves (10−8–10−3M) were constructed in the presence of nisoxetine [a NE transporter inhibitor (Nxt: 1 μM)] or vehicle (water). Prazosin (Pz: 1μM), an α1‐adrenoreceptor antagonist, was added after the maximum contraction‐induced by Tyr was obtained. NE concentration (ng/g tissue) was high in main renal arteries and their branches of −PVAT strips (913.9±68.2; n=4) and in isolated PVAT taken from these vessels (523.7±68; n=5). Presence of PVAT did not alter the efficacy of Tyr‐induced contraction, indicated by the concentration to produce the maximum effect (+PVAT: 12.3±3.3mN, − PVAT: 14.5±1.3mN; n= 4–5) or the potency, indicated by the negative logarithm (−log) of half maximal effective concentration (EC50) (+PVAT: −4.1±0.1, − PVAT: −4.6±0.1; n=4–5). Similarly, both pharmacological parameters of Tyr‐induced contraction were not altered by the Nxt: after incubation with Nxt, the efficacy of Tyr‐induced contraction +PVAT was 14.4±3.1mN (n=8) and −PVAT= 10.9±2.9mN (n=5) and its potency +PVAT was −3.7±0.1 (n=8), and −PVAT= −3.74±0.2 (n=5). Pz reduced the maximum effect of Tyr by 90±5% in all of the rings. We conclude that Tyr‐induced contraction of the renal arteries is due to α1‐adrenoreceptor activation by release of NE in a manner independent of PVAT and the NE transporter. Furthermore, and contrary to our hypothesis, it is likely that the effects of Tyr are due exclusively to the release of NE from sympathetic nerves ‐‐ densely present in renal vessels – and not to release of NE from adjacent PVAT.

Support or Funding Information

FAPESP (2015/25822‐9); HL70687.
Developmental Changes in Respiratory Inductance Plethysmography (RIP) Parameters
Authors: Shaffer Thomas H. , Balasubramanian Sona , Wang Yanping , Rahman Tariq
Published: November 2023

Rationale

Monitoring of respiration is crucial for rapid diagnosis, treatment, and critical care of patients in various clinical settings. The current noninvasive method for respiratory monitoring is (RIP) which requires post hoc analysis to calculate respiratory indices: respiratory rate (RR), phase angle (Φ), labored breathing index (LBI), and percent of ribcage contribution to breathing (%RC). Although studies have provided patient RIP values and corresponding age‐matched normal values; these studies lack global normative data for a wide age group.

Objective

To compile and calculate normative respiratory indices from studies including a large range of ages in order to develop a database of age‐dependent physiological values for (RIP) parameters.

Methods

The PubMed database, journals, reviews and book chapters were screened for RIP parameters in healthy individuals. Corresponding SEM or SD values are presented, along with number of subjects, age range (preterm infants to adults), sex, and body position. Based on regression analysis of RIP data vs. age; regression equations were calculated. Furthermore, 95% CI and 85% CI confidence intervals were derived.

Results

Depending on the RIP parameter, data from 200 – 900 subjects were utilized in the development of tables, graphs, and regression correlations. Since the database is rather large, we present only typical results herein, although data for all RIP parameters were analyzed. The correlation (R2=0.94; P< 0.001) between RR and postconception age was excellent (range: preterm infants to adults). As shown, the mean RR values were within or close to the 95% confidence intervals(Fig 1). The regression correlation between %RC and postconception age in years (number of data points, n = 36) was (R2 = 0.41; P<0.05).(Fig. 2).

Conclusion

The presented database will provide caregivers with the ability to compare RIP data for patients with age‐matched normal controls, identify patients with higher risk of pulmonary complications and guide respiratory therapy. This is the first study that provides a compilation of normative RIP data across all age groups. This study has both research and clinical significance to further assist in early and rapid diagnosis of PF. Also, these data address the greater need to determine normative ranges for each WOB parameter for neonates and children. The regression graphs from the data analysis demonstrate that the greatest changes in RR with age occur during early development.

Support or Funding Information

This study was funded by The Nemours Foundation; The University of Delaware, Center for Advanced Technology (CAT) Program Grant #44058 (Tariq Rahman and Thomas H. Shaffer; CO‐PIs); and NIH COBRE Grant P30 GM114736 (Thomas H. Shaffer; PI).
Mas Antagonist Prevents the Anti‐inflammatory Effect of Exercise in a Model of Chronic Allergic Lung Inflammation
Authors: Campagnole‐Santos Maria Jose , Gregorio Juliana Fabiana , Magalhaes Giselle Santos , Motta‐Santos Daisy , Casssini‐Vieira Puebla , Barcelos Luciola , Rodrigues‐Machado M Gloria , Vieira Maria A R , Santos Robson A S
Published: November 2023

Aerobic exercise training attenuates asthma‐induced airway inflammation, pulmonary remodelling and bronchial hyperresponsiveness. In addition, aerobic exercise increase circulating and tissue levels of angiotensin‐(1–7) [Ang‐(1–7)], which was shown to attenuate inflammation in different diseases. In the present study, we evaluated whether Ang‐(1–7) is involved in the beneficial effects of aerobic training in an experimental model of chronic allergic lung inflammation (asthma). BALB/c mice were subjected to a chronic protocol of asthma induced by ovalbumine (OVA) immunization (4 i.p. injections of OVA 14 days apart) and sensitization (OVA inhalation, 3 times a week during 4 weeks). Simultaneously to sensitization period, part of the animals were treated with the antagonist of Ang‐(1–7) receptor Mas (A779, 1μg/h; for 28 days) and trained in a treadmill (TRE; 60% of the maximal capacity, 1h/day, 5 days/week during 4 weeks). Non‐asthmatic and sedentary mice (controls) received saline i.p. and inhalation with saline at same time points of experimental groups. The serum IgE levels were determined by ELISA, the airway remodelling by histology, infiltration of inflammatory cells in the lung by enzymatic activity assay. The gene expression of PGC‐1α was determined by qRT‐PCR and the protein expression of fibronectin in the lung by Western blotting. Treatment of asthmatic and trained animals with A779 prevented: i) the reduction in serum IgE levels (23±10 U/ml vs 0±0 U/ml in OVA‐TRE); ii) the reduction in extracellular matrix deposition in the airways (32±1% vs 17±2% in OVA‐TRE); iii) the reduction in the alveolar wall thickening (3±0.3 μm2 vs 1.8±0.1 μm2 in OVA‐TRE); iv) the reduction in MPO enzyme activity (neutrophils infiltration; 1.51±0.11 D.O./mg vs 1.01±0.06 D.O./mg in OVA‐TRE); v) the decrease in protein expression of fibronectin in the lung. Physical training was confirmed by the increase in PGC1‐α in OVA‐TRE (1.85±0.14 a.u.) and OVA‐TRE‐A779 (1.62±0.48 a.u.) in comparison to sedentary animals (0.96±0.15 a.u.). These data suggest that Mas receptor activation is involved, at least in part, in the anti‐inflammatory and anti‐fibrotic effect of aerobic training in animals subjected to an experimental model of chronic pulmonary lung inflammation. FINNANCIAL SUPPORT: FAPEMIG, CAPES, CNPq, INCT‐Nanobiofar

Support or Funding Information

FAPEMIG, CAPES, CNPq, INCT‐Nanobiofar
Interaction between Chronic Intermittent Hypoxia and Aging in the Lung Tissue
Authors: Brinkman Jacqueline , Torres Marta , Broytman Oleg , Farre Ramon , Almendros Isaac , Teodorescu Mihaela
Published: November 2023

Rationale

Aging is a powerful risk factor for obstructive sleep apnea (OSA). Chronic intermittent hypoxia (CIH), a key feature of OSA has been shown to lead to heterogeneous lung remodeling in rats, consisting of airways fibrosis and peripheral emphysema‐like formations. In humans, it is also known that with aging lung function declines, in part due to senile emphysema. Emphysema is caused by enhanced synthesis of matrix metalloproteinases (MMPs) by alternatively activated (M2‐polarized) macrophages and aberrant expression of neutrophil elastase (NE), a protease that destroys host tissue. The objective of this study is to examine the molecular interactions of aging and CIH in a mouse model.

Methods

Wild type C57BL/6j, female mice (n=3–4/group), aged 4 months (young) and 23 months (old) were exposed to either CIH, defined as 60 events per hour (40 seconds 20% O2 and 20 seconds 5% O2), for 6 hours per day, or normoxia (Nx), for 8 weeks. Mouse lungs were excised, frozen at −80 C, and analyzed for macrophage scavenger receptor (MSR1), a macrophage marker and NE by western blot. Total protein was resolved by SDS‐PAGE. Images were quantified by densitometry using ImageJ software.

Results

Protein levels of MSR1 (Figure 1A): 1) in the 4/CIH group was significantly higher than in the 4/Nx and comparable to 23/Nx group. NE protein levels (Figure 1B): 1) were highest in the 23/CIH and significantly different from 23/Nx group (p<0.05); 2) appeared to be comparable between 4/CIH and 23/Nx groups.

Conclusions

Lungs exposed to CIH have increased MSR1 protein expression to levels comparable to that of aged lungs; aging amplified the effects of CIH on NE levels. These results suggest that CIH leads to accelerated aging in the lung; various pathways may be more or less expressed.

Support or Funding Information

Department of Medicine Pilot Funds
Effects of Chronic Intermittent Hypoxia (CIH) on mTORC Signaling in the Lung
Authors: Brinkman Jacqueline , Torres Marta , Broytman Oleg , Farre Ramon , Almendros Isaac , Lamming Dudley , Teodorescu Mihaela
Published: November 2023

Rationale

The mechanistic target of rapamycin complex 1 (mTORC1) is a serine/threonine protein kinase that promotes anabolic processes (protein translation, lipogenesis and nucleotide syntheses) and limits catabolic processes, such as autophagy; thus, modulates senesce in various tissues. S6K1 and its downstream targets SKAR and S6 substrate are involved in mTORC1 signaling, whereas 4EB‐P1 is an inhibitory regulator of mTORC1‐induced protein translation. Chronic intermittent hypoxia (CIH)—the hallmark feature of sleep apnea, leads to heterogeneous remodeling in the lung, similar to “senile remodeling” (senile emphysema and fibrosis). However, whether CIH modulates the mTORC1 pathway to underlie these processes remains unknown. We hypothesized that CIH leads to downregulation of mTORC1 signaling, contributing to accelerated aging in the lung.

Methods

Wild type C57BL/6j, female mice (n=3–4/group), aged 4 months (young) and 23 months (old) were exposed to either CIH, defined as 60 events per hour (40 seconds 20% O2 and 20 seconds 5% O2), for 6 hours per day, or normoxia (Nx), for 8 weeks. Mouse lungs were excised, frozen at −80 C, and analyzed for phosphorylated (P) S6K, S6 and 4EB‐P1 protein levels by Western blot. Total protein was resolved by SDS‐PAGE. Images were quantified by densitometry using ImageJ software. Data were expressed as ratio of phosphorylated component/total protein.

Results

P‐S6K levels (Figure 1A): 1) in the 4/CIH group was significantly lower than in the 4/Nx and comparable to 23/Nx group; 2) in the 23/CIH group trended to be lower than in the 23/Nx. There were no group differences in PS6 levels (p=0.92). Meanwhile, phosphorylated 4E‐BP1 levels (Figure 1B): 1) in the 4/CIH group were higher than in 4/Nx and comparable to 23/Nx group; 2) whereas, in the 23/CIH tended to be higher than the 23/Nx group.

Conclusions

Lungs exposed to CIH demonstrate reduced downstream mTORC1 P‐S6K signaling, concurrent with increased levels of the inhibitory regulator of mTORC1‐induced protein translation, 4E‐BP1; aging may amplify these effects. These results suggest that CIH could lead to reduced mTOR‐induced protein synthesis and accelerated aging in the lung.

Support or Funding Information

School of Medicine Pilot funds
Estradiol changes mitochondrial morphology into complexity in response to exercise
Authors: Nakano Daiki , Machida Shuichi
Published: November 2023

Mitochondria in mammalian cells undergo morphological remodeling via dynamic fusion (maintaining functional mitochondria) and fission (removing dysfunctional mitochondria) events to adapt to external exercise‐associated stimulation and functional needs. The purpose of this investigation was to determine the effect of acute exercise on the mitochondrial morphology of skeletal muscle within the phases of the menstrual cycle. Twenty‐four female Wistar‐Imamichi rats (15‐week‐old) were divided into four groups: low level of estradiol + sedentary (LE + S), low level of estradiol + acute treadmill exercise (LE + Ex), high level of estradiol + sedentary (HE + S) and high level of estradiol + acute treadmill exercise (T+ Ex). Vaginal smears for all animals were used to determine the menstrual cycle phase. The acute treadmill exercise in LE + Ex and HE + Ex groups involved a treadmill run at 60% V(■)O2 max for 120 min. Upon completion of each intervention, the red portion of the gastrocnemius muscle was dissected. Approximately 900 intermyofibrillar mitochondria were analyzed by transmission electron microscopy. We estimated the shapes and sizes of sampled mitochondria using ImageJ software based on measurements of surface area, perimeter, aspect ratio (AR), form factor (FF), circularity, and roundness. The mitochondrial shapes and sizes did not differ between the LE + S and HE + S groups. Mitochondrial morphological changes were also absent in the LE rats (LE + S vs. LE + Ex), whereas indicators of the fusion event were present after the acute treadmill exercise in HE rats (HE + S vs. HE + Ex), i.e., increased surface area (+20%), perimeter (+31%), AR (+29%), and FF (+42%), as well as decreased circularity (−22%) and roundness (−16%). In conclusion, mitochondrial adaptations in HE rats in response to exercise may be due to fusion.
Loss of UCP1 improves ex vivo aortic vasomotor function in female but not male mice despite similar susceptibility to metabolic dysfunction
Authors: Winn Nathan C , Grunewald Zach I , Gastecki Michelle L , Woodford Makenzie L , Welly Rebecca J , Clookey Stephanie L , Ball James R , Gaines T'Keaya L , Karasseva Natalia G , Kanaley Jill A , Sacks Harold S , Vieira‐Potter Victoria J , Padilla Jaume
Published: November 2023

Female rodents are more insulin sensitive than males which may be partly attributed to greater brown adipose tissue (AT) activity and uncoupling protein 1 (UCP1) content. Accordingly, we tested the hypothesis that loss of UCP1 would produce greater metabolic disturbances in females than males such that sex differences in insulin sensitivity would be abolished. Furthermore, we hypothesized that whitening of thoracic periaortic brown AT caused by UCP1 deletion would be accompanied with impaired thoracic aortic function. Last, because UCP1 exerts antioxidant effects, we examined whether UCP1 deficiency‐induced metabolic dysfunction is mediated by oxidative stress. Compared to males, female mice had lower glucose and HOMA‐ and AT‐insulin resistance (IR) despite no differences in UCP1 protein content in interscapular brown AT. UCP1 ablation caused similar increases in HOMA‐IR and AT‐IR in both female and male mice such that no sex x genotype interactions were evident. In spite of UCP1 loss‐induced IR and whitening of thoracic periaortic brown AT, UCP1 knockout female mice exhibited improved aortic vasomotor function. Moreover, UCP1 ablation did not produce increased interscapular brown AT oxidative stress. Similarly, administration of the free radical scavenger Tempol for 8 weeks in drinking water did not abrogate lack of UCP1‐induced increases in adiposity, hyperinsulinemia, or liver steatosis. Taken together, our findings indicate that 1) loss of UCP1 provokes similar induction of IR in female and male mice; 2) paradoxically, deletion of UCP1 improves ex vivo aortic vasomotor function in female but not male mice; and 3) the metabolic disruptions caused by UCP1 ablation are not contingent upon increased oxidative stress.
Sex differences in the role of urothelium in rat bladder contractile function
Authors: Szasz Theodora , Burgess Beth , Webb R. Clinton
Published: November 2023

Bladder dysfunction is a prevalent condition associated with diabetes, aging, and cardiovascular disease. Despite sex differences in the risk factors, clinical findings and prevalence of diseases associated with bladder dysfunction, the role of sex differences in the physiological regulation of bladder function has been poorly investigated. We have previously observed that contractile responses to both carbachol (CCh) and electrical field stimulation (EFS) were greater in the male than the female rat bladder segments in both the presence and absence of urothelium. We hypothesized that sex differences in the role of urothelium in bladder contraction may underlie the sex differences observed clinically in bladder dysfunction. Female and male rat bladder contractile responses to CCh were measured in the presence and absence of the cyclooxygenase (COX) inhibitor indomethacin and the nitric oxide synthase (NOS) inhibitor L‐NAME, and in the presence and absence of urothelium. We observed that the presence of urothelium inhibited CCh‐induced contraction in the bladder, and this inhibitory effect was larger in the female than the male bladder (ΔEmax CCh[−Uro +Uro] (mN/mg) female=1.38±0.58, male=0.53±0.31). Incubation of bladder segments with indomethacin reverted the inhibitory effect of urothelium on CCh‐induced contraction in the male, but not the female bladder. Incubation of bladder segments with both indomethacin and L‐NAME reverted the inhibitory effect of urothelium on CCh‐induced contraction in bladder segments from both sexes. Our data suggest that there are sex differences in the physiological contractile function of the rat bladder in basal conditions, and that the contribution of COX to urothelium‐mediated contractile mechanisms is greater in the male than the female.

Support or Funding Information

NIDDK Diabetic Complications Consortium (DiaComp, www.diacomp.org), grant DK076169.
Sex differences in molecular mechanisms of vascular aging
Authors: DuPont Jennifer , Davel Ana , McCarthy Joseph , Aronovitz Mark , Baur Wendy , Jaffe Iris
Published: November 2023

Hypertension (HTN) is the most prevalent cardiovascular disease risk factor. Although HTN incidence rises profoundly with age in both sexes, females are relatively protected when they are young and after menopause, females ultimately exceed males in the incidence and adverse outcomes of HTN. In male mice with SMC‐specific deletion of the mineralocorticoid receptor (MR‐KO), we showed protection from the aging‐associated rise in blood pressure (BP). We show that in males, the mechanism involves SMC‐MR transcriptionally repressing vascular miR‐155 expression with age, which then promotes an increase in expression of miR‐155 target genes, Cav1.2, the pore‐forming subunit of the L‐type calcium channel (LTCC) and the angiotensin II type 1 receptor (AT1R). Further studies revealed that restoration of SMC‐specific miR‐155 rescues the aging phenotype observed in male mice. Specifically, raising SMC‐miR‐155 expression resulted in decreased Cav1.2 and AT1R expression and LTCC‐and AT1R‐mediated vasoconstriction. In female mice, however, Cav1.2 and AT1R expression did not change with age. Additionally, vasoconstriction to LTCC agonist BayK‐8644 and Ang II are not increased in aging females compared to young females. These results suggest that mechanism of vascular aging and BP control are distinct between males and females. These data support that sex‐specific therapies may be beneficial in managing vascular aging and BP control.

Support or Funding Information

Supported by HL095590‐05, HL119290, and 15POST21300000.
Bmal1 knockout rats show sex differences in the rhythms of diurnal sodium excretion
Authors: Johnston Jermaine G. , Jin Chunhua , Pollock David M.
Published: November 2023

Previous studies suggest that core clock genes generally function to facilitate Na conservation such as Per1 effects to mediate the renal effects of aldosterone. Mouse models have shown that knockout of the Bmal1 gene results in multiple pathologies and a shortened life span. However, little is known about the function of Bmal1 in control of Na handling by the kidney in the rat. Therefore, we used a newly created whole‐body Bmal1KO knockout rat model (MCW Gene Editing Rat Resource Center) to determine the impact of Bmal1 gene deletion on the diurnal rhythms of sodium excretion (UNaV). Loss of Bmal1 expression was verified by Western blot. Male and female rats homozygous for the mutation (homo) and their littermate controls (wt) were implanted with telemetry transmitters to monitor mean arterial pressure (MAP). After a recovery period of at least one week, baseline urine samples were collected in 12hr light/dark intervals. The night‐day difference in UNaV was evident in wt, but not homo male rats (415 ± 87 and 14 ± 72 μEq Na/12hr wt vs. homo, n=6 and 4, respectively; P<.05). This loss of diurnal rhythm was not observed in female homo rats (274 ± 79 and 205 ± 43 μEq Na/12hr wt vs. homo, n=5 and 9, respectively; P<.05). Rats were then given a single 900μEq Na salt load (NaCl) in 1mL of water by oral gavage at the beginning of their inactive (Zeitgeber Time (ZT) 0) or active (ZT12) period. Despite the differences in night‐day UNaV between male wt and homo rats, both groups exhibited a prompt natriuretic response to an acute salt load, excreting most of the excess salt in the first 12 hours after being given either a salt load at ZT0 or ZT12. However, when comparing the total 24hr response to the salt load, the homo group displayed a higher change in UNaV compared to wt when the salt load was given at ZT0 (706 ± 78 and 1123 ± 50 μEq Na/24hr wt vs. homo, n=6 and 4, respectively; P<.05). Again, this difference was not observed in female rats. There were no significant differences in MAP between genotypes in either sex. These data suggest that rats lacking Bmal1 expression display a blunted rhythm of diurnal UNaV in male but not female rats. In addition, male Bmal1KO rats display an enhanced ability to excrete a salt challenge consistent with a sodium conserving function of clock genes by the kidney.
Constructing 3 Dimensional Models of Sensory and Motor Tracts of the Spinal Cord as an Active Learning Technique
Authors: Knight Sarah
Published: November 2023

The aim of this study was to measure the effectiveness of making 3 dimensional models as a method to enhance student understanding, enthusiasm and retention of the anatomy and physiology of pathways of the spinal cord. A total of 20 students participated in this study and were enrolled in a two semester undergraduate Human Anatomy and Physiology course taught at American University.

Students worked in self‐selected groups of between 5–7 students. Following a lecture on the motor and sensory tracts of the spinal cord as part of the nervous system module, students were given the task of constructing 3 dimensional models of a number of pathways in order to visualize the different neural pathways in relation to each other in a hands‐on manner. Students were responsible for constructing models of a list of pathways of the spinal cord from colored card and ribbon. Pieces of card represented cerebrum, cerebellum, medulla and spinal cord and ribbon was used to trace the pathways. Students constructed and labelled multiple pathways on each model. The students were able to use their notes and text book as reference material while constructing the models. Upon completion of the task we reviewed the models as a class for 5–10 minutes and students had the opportunity to correct any errors and misunderstandings. Students completed an anonymous questionnaire in order to obtain feedback on the effectiveness of the model making exercise and the students experience.

Of the 20 students polled 60% agreed or strongly agreed with the statement that the exercise increased their learning of the topic. At least 85% of participants agreed or strongly agreed that working as part of a group was beneficial in this exercise. More than 60% of the students polled reported that the time spent on the exercise was sufficient. However, in the written feedback from students 50% requested more time for discussion after the exercise. Other comments included preferring smaller working groups and more discussion time before the exercise.

One drawback from this study was the absence of a control group of students that didn't participate in the model making exercise. This therefore prevented comparison of how the model making task affected student learning.

In conclusion the results indicate that the students reported a perceived benefit from the model making exercise however adjustments such as increasing discussion time afterwards and using smaller working groups of students may improve the outcomes of this exercise.
Learning phundamental physiology with phUn Augusta scientists
Authors: Irsik Debra L , Abdul Yasir , Ferreira Neto Hildebrando C. , Choudhary Vivek , Crislip Ryan , Gillis Ellen , Klee Nicole S. , Quinones Patricia Martinez , McCarthy Cameron G. , Payne Anthony , Szasz Theodora , Valenzuela John Paul
Published: November 2023

The American Physiological Society sponsors Physiology Understanding Week to excite children about careers in science. Augusta University physiologists held events at 3 local schools, using programs created to appeal to different age groups.

The first program was geared toward 7th graders. After an introduction to physiology and careers in science, 100 students rotated through 5 different stations. They used a microscope to observe the eye, brain, lung and kidney histology. A fixed cow heart and anatomical models served to explain the structure and function of the heart, kidney and lung. Students learned about the cardiovascular system by measuring blood pressure changes after isometric contractions and by observing heart rate increases after a stressful activity. Finally, students tested their skills in a laparoscopic surgery teaching unit.

The second program was designed to teach simpler scientific concepts to 140 4th and 5th graders. Students measured their lung capacity. They also learned about nutrition by measuring the salt and sugar content in different foods. Other concepts, such as the GI and renal function, the role of mucus, and the spread of infection through sneezing were also explored.

Classes ended with a question and answer session, distribution of PhUN week bags, and a group photo. The students and teachers enjoyed interactive learning of physiology.
Neuroadaptive Events In Adult Offspring Induced By Perinatal Chronic Stimulation Of The Renin‐Angiotensin System (RAS)
Authors: Macchione Ana Fabiola , Dadam Florencia , Antunes‐Rodrigues Jose , Vivas Laura
Published: November 2023

Studies of last decades give evidence of the important role of the perinatal environment in the developing systems being able to result in permanent changes of the physiology and the metabolism of the new individual. Evidences from our and other laboratories indicate that mechanisms and circuits involved in the hydrosaline balance may be vulnerable to perinatal programming effects. This hydroelectrolytic‐programming may be given by intrauterine and/or postnatal environment alterations.

In this work, the programming model utilized was the chronic stimulation of RAS given by the partial aortic ligation (PAL) in dams before the matting and along the gestation and lactation. Water and sodium intake patterns and neuronal activity (Fos‐ir, Fos‐immunostaining) were investigated in adult offspring subject to a sodium depletion made with Furosemide (40mg/kg, sc) and low sodium diet [F/LSD]. Maternal fluid intake, plasma electrolyte levels and plasma renin activity (PRA) were also studied at weaning in mothers and female offspring. The perinatal programming groups (PP) were: i) PAL/hypertonic sodium solution/water [PAL]; ii) sham surgery/hypertonic sodium solution/water [Sh‐Na] and iii) only water [Sh‐W]. The PP started one week before mating and finished at weaning.

PAL‐dams showed an increased PRA levels and water and total fluid intakes, and a diminished in osmolality levels without being altered their natremia levels. The two last results probably were a consequence of the dipsogenic effect of the PAL model. In contrast, PAL‐pups showed an increase in natremia and osmolality levels. Possibly, this plasma osmolyte accumulation in PAL pups may be origin by renal immaturity that leads to a deficient excretory function unable of eliminated the excess of circulating sodium.

A decrease in water and sodium intake was observed in adult PAL‐offspring subject to F/LSD. This behaviour was accompanied by an increase in the number of Fos‐ir cells in the dorsal raphe nucleus. Because this nucleus is part of a circuit that tonically inhibits fluid intake, it is possible to assume that the decreased fluid intake in PAL‐offspring may be due to a desensitization of this nucleus, preventing the normal triggering of the fluid ingestion response induced by F/LSD. These data shown neuroadaptive events, probably such as a consequence of long‐term perinatal programming processes that affect reception of signals and activity of brain circuits involved in hydrosaline homeostasis and in fluid intake regulation.

Support or Funding Information

This work was supported by ANPCyT, CONICET, MinCyT and SECyT.