bluuebunny/crossref_metadata_2025_split huggingface dataset:
Salivary biomarkers as assessment of metabolic function and inflammation in children with obesity
Authors: Kemp Keri , Orihuela Catheryn , Evans Retta , Mrug Sylvie 
Published: May 2024

Childhood obesity increases adult metabolic and cardiovascular disease risk. Using blood for long-term biomarker analysis in children is problematic because of the discomfort, pain, and anxiety associated with frequent blood draws. Noninvasive methods are vital for predicting childhood obesity complications. This study examined body mass index-for-age percentile scores (zBMI) as a predictor of salivary biomarkers of metabolism and inflammation, including insulin and C-Reactive Protein (CRP), over time. A school sample of 288 adolescents (Mage = 12.1 at study initiation; 46% female; 48% Black, 37% non-Hispanic White, 15% Hispanic or other minorities) were enrolled from greater Birmingham, Alabama. Participants provided salivary samples across four days once per year from 2019–2021. In year 1 of the study, 19% of adolescents were overweight, 18% had obesity, 6.6% had severe obesity, and 7.3% had very severe obesity based on the 2022 CDC Extended BMI-for-Age Growth Charts. Multivariable models showed that lower parental income was associated with an increased risk of obesity (OR = 0.91; 95% CI = 0.85, 0.97; p = 0.009). Greater concentrated poverty, a measure of spatial distribution of socioeconomic deprivation, was associated with an increased risk of severe or very severe obesity (OR = 1.58; 95% CI = 1.01, 2.46; p = 0.043). However, race/ethnicity was not associated with obesity risk. Longitudinal analyses showed that greater zBMI in year 1 was associated with greater salivary CRP ( β = 0.188, SE = 0.058, p = 0.001) and insulin ( β = 0.263, SE = 0.076, p<0.001) in years 2 and 3 of the study after adjusting for year 1 biomarker levels, sex, race/ethnicity, and concentrated poverty. Multivariable models indicated that an accelerated increase in zBMI/year was associated with an accelerated increase in CRP/year ( β = 0.119, SE = 0.048, p = 0.014), but there was no association between the rates of change in zBMI and insulin. Future analyses will incorporate additional hormones, such as adiponectin, and inflammatory cytokines measured in saliva. In conclusion, these results indicate that salivary biomarkers can capture physiological differences associated with zBMI in school-age children. Saliva may constitute a useful non-invasive tool for evaluating markers of inflammation and/or metabolism related to zBMI in children outside clinical settings. This research was supported by an Institute of Education Sciences, U.S. Department of Education Grant (R305A180074) to SM and RE and a National Heart, Lung, and Blood Institute K99R00 Grant (1K99HL165091-01A1) to KMK. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Ad Libitum Drinking Prevents Body Mass Loss Across Consecutive Workdays in Heat
Authors: Rawlings Alexander , Kozlin Michael , Przybysz Johnathan , Cavuoto Lora , Schlader Zachary , Pryor Riana 
Published: May 2024

Hydration practices across consecutive days of heavy-intensity work in heat when fluid is freely available is unknown. Without this information it remains unknown whether hydration modifies heat strain under hot working conditions and whether worker recommendations adequately maintain hydration status. We hypothesized that participants would maintain hydration status including daily percent change in body mass across workdays. Fifteen healthy, unacclimated participants (7 Females, Age: 27±6 y, Body mass: 75.0±14.4 kg, Body fat: 26.6±5.8%) completed three consecutive days (Day 1, Day 2, Day 3) of 4 h of 395±10 W work to a work/rest cycle of 45/15 min in a 36.3±0.8°C, 21±5% relative humidity environment. Participants were offered 237 mL of a sport drink every 20 min to consume ad libitum. Urine flow rate (UFR) was measured before work. Urine specific gravity (USG) and nude body mass were measured before and after work. Thirst and fluid consumption were measured throughout work. USG before work was not different between Day 1 (1.013±0.010) and Day 2 (1.013±0.010, p=0.822), but was greater before work on Day 3 (1.015±0.010, p=0.046) compared to Day 2. Change in USG from before to after work was not different between Day 1 (+0.003±0.008) and Day 2 (+0.000±0.006, p=0.123), but was lower on Day 3 (-0.002±0.006, p=0.021) compared to Day 1, with no difference between Day 2 and Day 3 (p=0.058). Before work body mass was not different across days (p=0.103). Daily percent change in body mass was not different across days (p=0.366, Day 1: 0.53±1.11%, Day 2: 0.18±0.95%, Day 3: 0.18±0.81%), indicating weight gain each day. Sweat rate (p=0.790) and UFR (p=0.469) were not different among days. Participants consumed 77±18% (Day 1), 82±19% (Day 2), and 82±16% (Day 3) of fluid offered (p=0.401), equaling 31±10 mL/kg (Day 1), 33±11 mL/kg (Day 2), 33±10 mL/kg (Day 3) (p=0.370). Maximum thirst was greater on Day 1 (3.5±1.1) compared to Day 3 (2.9±1.0, p=0.045) with no difference between Day 1 and Day 2 (3.4±1.4, p=0.648) or between Day 2 and Day 3 (p=0.121). This study demonstrates consistent hydration practices and no differences in hydration status across three consecutive days of high-intensity work in heat when fluid is freely available. Under these conditions, workers can consume fluids ad libitum and worker recommendations for hydration during heat stress should be revisited. This project was funded my the National Institute for Occupational Safety and Health (1K01OH012016-01A1). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Homeostatic regulation of circuit activity through temperature-sensing rather than activity-sensing
Authors: Cannon Delaney , Santin Joseph 
Published: May 2024

Electrical signaling between nerve cells coordinates essential functions of the body. However, neurons face their own regulatory challenges, as they need to produce relatively constant activity patterns as the environment changes. Like homeostatic control that occurs within other organ systems, neural circuits are subject to homeostatic regulation as well, whereby deviations from a set point level of activity elicit corrective responses to maintain circuit output. To achieve this end, neural systems are thought to sense variables that relate to neuronal activity, such as firing rate, ion concentrations, and neuromodulators, to detect when an imbalance in activity occurs. While recording rhythmic motor activity associated with breathing in the American bullfrog, we made the surprising observation that acute cooling to 10°C silenced network activity, but after several minutes, bursting resumed and then overshot baseline frequency upon rewarming. Burst frequency drifted back to the initial value over tens of minutes, consistent with the fast regulation of an activity set point (n=9). Time controls with no temperature changes were stable throughout this period (n=7). Exposing the network to manipulations inducing similar perturbations that silence activity over the same timescale– hypoxia (n=6), glycine (n=6), and tetrodotoxin (n=4)– did not engage feedback regulation. These results suggested that temperature sensing, rather than activity sensing, controls network output. Cation channels activated by cooling in amphibians (TRPM8, n=4; TRPV3, n=4) and L-type Ca2+ channels (n=4) did not contribute to these responses. Experimental activation of the Na+/K+ pump with monensin, which raises intracellular Na+, reduced the compensation response both in the cold (p=0.01, unpaired t-test) and in the overshoot phase following warming, suggesting that cold-dependent inhibition of the Na+/K+ pump enhances network excitability. Finally, NMDA-glutamate receptors played a role in constraining the amount of compensation, as block of NMDARs with D-APV led to compensation that greatly exceeded those observed in the control experiments (n=5, p<0.0001, unpaired t-test), remaining elevated above baseline upon rewarming in all experiments. The cellular mechanisms by which raising intracellular Na+ with monensin and NMDAR signaling influence compensation responses are ongoing. Overall, these results uncover a temperature-sensitive control system that regulates activity in neural circuits. Our results introduce that some neural systems may replace typical activity sensors with regulatory systems that are instead tuned to environmental cues to defend activity set points. R01NS114514, R15NS112920-01A1. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
β-catenin Signaling Drives Intestinal Epithelial Production of Interleukin-33
Authors: Schumacher Michael , Thai Megan , Liu Cambrian , Frey Mark 
Published: May 2024

Background: Interleukin (IL)-33 is a key responder to intestinal infection, injury, and inflammation. It drives protective epithelial re-modeling via a stromal-epithelial circuit. However, we know little about the regulation of epithelial IL-33 at homeostasis and in disease. Our group previously found that colonic epithelial production of IL-33 is restrained by the inflammation-responsive signaling regulator, Sprouty2. Loss of Sprouty2 activates GSK3β (a key mediator of canonical Wnt/β-catenin signaling) and induces IL-33 in the colon, but the specific role of β-catenin and Wnt pathway components involved in this induction are unknown. Hypothesis: Canonical Wnt/β-catenin signaling induces colonic epithelial expression of IL-33. Methods: Bulk and single-cell RNAseq were performed on colons from mice with an intestinal epithelial-specific Sprouty2 deletion (Spry2IEKO) or littermate controls and subjected to gene enrichment and Panther pathway analyses. Colonic epithelial cell cultures were treated with Wnt3a and R-spondin to activate β-catenin signaling; small molecule inhibitors were used to inhibit CBP- or p300-mediated β-catenin signaling arms. IL-33 levels were assayed by qPCR and ELISA. Results: Analysis of significantly altered genes in Spry2IEKO colons by Panther analysis found an enrichment in genes regulated by canonical Wnt signaling (FDR 3.72E-02), correlating with increased IL-33 observed in these mice. Analysis of single-cell RNAseq suggests colonic epithelial IL-33 is predominantly expressed in the stem and progenitor cell niche. Colonic epithelial cells treated with Wnt ligand showed a significant induction in IL-33 (p<0.05) at both RNA and protein levels. Inhibition of CBP-mediated but not p300-mediated β-catenin signaling prevented IL-33 induction, correlating with decreased expression of the CBP inhibitor, Psen1, in Spry2IEKO colons. Conclusion: CBP-mediated β-catenin signaling promotes colonic epithelial expression of IL-33. Acute inflammation-mediated loss of Sprouty2 drives IL-33 induction in the stem cell niche as a protective response to injury or infection. NIH K01DK131390 (MS); Crohn's and Colitis Foundation CDA (MS); NIH R01DK135954 (CL); NIH R01DK119694 (MF). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Mitochondrial NAD Profile in a Rat Model of Attention-Deficit/Hyperactivity Disorder
Authors: Schwarzer Hannalyn , Brandauer Josef 
Published: May 2024

Mitochondria require nicotinamide adenine dinucleotide (NAD) to satisfy cellular energy needs. Mitochondrial stress has been reported in skeletal muscle tissue of humans with attention-deficit/hyperactivity disorder. NAD deficiency may indicate mitochondrial stress that can be assessed through NAD concentration assays and Western blotting of Nampt and Sirtuin 3 (SIRT3) proteins. Nampt is the rate-limiting enzyme in intracellular NAD recycling, while SIRT3 is an NAD-dependent protein deacetylase that regulates mitochondrial mass and activity. The objective of this study was to investigate skeletal muscle and liver tissues of rat strains that exhibit behaviors associated with ADHD. We hypothesized that tissues from rat models with ADHD-like behavior (Lewis and F344 strains) would have lower NAD concentrations and reduced Nampt and SIRT3 protein expression relative to the control strain (Sprague Dawley). To examine this hypothesis, we performed fluorescence tissue NAD concentration assays. We found a significant difference in liver NAD between Sprague Dawley and F344 rats (Sprague Dawley, 0.14 ± 0.07 mM/mg [mean ± standard deviation], F344, 0.22 ± 0.11; p < 0.05). Western blot analysis for Nampt and SIRT3 proteins revealed a significant difference between the F344 and Sprague Dawley rats for Nampt protein in the extensor digitorum longus (EDL) muscle (Sprague Dawley, 1043930 ± 303677 arbitrary units [AU], F344, 1729014 ± 553568 AU; p < 0.05). Our results indicate minor differences in tissue NAD concentration and Nampt protein expression in rat models with ADHD-like behaviors. This could be indicative of differential mitochondrial function in skeletal muscle or liver tissues. Further studies will examine the implications of increasing nicotinamide riboside in the skeletal muscles to observe the effects of NAD functioning. This work was supported by funds provided by the Cross-Disciplinary Science Institute at Gettysburg College (X-SIG) (HMS, JB) and a Gettysburg College Professional Development Grant (JB). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Exploring the synergistic potential of probiotics and vitamin D to ameliorate acute TNBS-induced colitis in mice
Authors: Lopez Jonathan , Ramos-Plaza Vivianka , Rodriguez-Morales Bryan M. , Cruz Myrella L. , Appleyard Caroline B. 
Published: May 2024

Inflammatory Bowel Disease (IBD), either Crohn’s disease or Ulcerative Colitis, are diseases characterized by chronic inflammation of the gastrointestinal tract, disruption of mucosal barrier, gut dysbiosis and vitamin D deficiency. The use of probiotics or vitamin D supplements have been studied individually in different colitis models to determine their beneficial effects by increasing tight junction proteins such as occludin. However, the synergistic effects of combining these treatments to target tight junction expression are still unknown. Therefore, the objective of this research was to demonstrate the effcacy of probiotics and high dietary vitamin D to ameliorate colonic inflammation by increasing mucosal barrier integrity. We hypothesized that co-administration of a probiotic mixture with vitamin D would reduce colitis-induced inflammation by increasing tight junction expression. For the methodology, male and female C57BL/6 mice were divided into four treatment groups: Colitis+Vehicle (n=10), Colitis+Probiotic (n=10), Colitis+Vitamin D (n=11), Colitis+Probiotic+Vitamin D (n=7). Animals received seven days of pretreatment with Vivomixx probiotics in water, high vitamin D (5IU/g) in food, or both. On day 7, animals were anesthetized lightly, and colitis induction was done by intracolonic administration of 0.1mL of 4mg TNBS in 30% ethanol. Water, food, and body weight were monitored daily. Animals were sacrificed on day ten, the colonic tissue was removed and assessed for inflammation then stained for occludin expression by immunofluorescence, and probiotic colonization was confirmed within fecal samples by RT-PCR amplification of S. Thermophilus gene. Results indicate that all animals decreased weight after colitis induction, but only animals receiving probiotic had a slight recovery by day 10. Animals receiving the probiotic mixture had higher S. Thermophilus expression in fecal samples compared to vehicle (p<0.001) indicating appropriate colonization. A significant reduction in macroscopic damage score (3.92 vs. 7.42, p<0.05) and microscopic score (3.42 vs 7.20, p<0.01) was found in animals with Probiotic+Vitamin D compared to vehicle. Although an increase in occludin expression was observed with probiotic administration it did not reach statistical significance. In conclusion, findings indicate a beneficial effect of combining probiotics and vitamin D on colonic tissue damage in an animal model of acute colitis but this did not impact the tight junction protein occludin. This work was supported by RISE (R25GM082406), G-RISE (T32GM144896), PRI MD Summer Program and Porter Physiology Development Fellowship. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Lack of Renal NHE1 Exacerbates Lithium-Induced Nephrogenic Diabetes Insipidus
Authors: Blanco Gabriella , Thomas Linto , Dominguez Rieg Jessica Ann , Rieg Timo 
Published: May 2024

The sodium-hydrogen exchanger isoform 1 (NHE1) is a transporter with roles in transepithelial Na+/H+ transport, intracellular pH (pHi), and cell volume regulation. Within the kidney, we localized NHE1 to the basolateral membrane of the distal parts of the nephron and collecting duct (co-labelling with AQP2 for principal cells and H+-ATPase B1 subunit for all 3 types of intercalated cells: type A, B, and non-A-non-B). We have previously shown that lack of NHE3 does not affect Li+ clearance, and other studies have shown that NHE1 transports Li+ preferably compared to NHE3. Therefore we hypothesized that NHE1 plays a critical role in Li+-induced nephrogenic diabetes insipidus. To address this question, we used newly generated mice which lack NHE1 protein in the tubule/collecting duct system (NHE1KS-KO) of the kidney. After baseline measurements, control (n=12) and NHE1KS-KO (n=9) mice were switched to a Li+-containing diet (0.2% LiCl [40 mmol/kg], Harlan Teklad, TD09326) for 4 weeks. Urine osmolality was not different between groups under baseline conditions (control: 2641±178, NHE1KS-KO: 2716±244 mmol/kg). In response to Li+, urine osmolality reached a minimum after 7 days that was sustained until the end of the experimental period. Of note, urine osmolality was ~500 mmol/kg lower in NHE1KS-KO versus control mice (1125±170 versus 475±94 mmol/kg, P<0.05) despite genotypes having comparable plasma Li+ concentrations (0.48±0.1 versus 0.45±0.1 mmol/L). Plasma Na+ concentrations were not significantly different under baseline conditions (149±0.5 versus 148±0.4 mmol/L) but increased to a significantly greater extent in NHE1KS-KO versus control mice (156±1.9 versus 152±0.5 mmol/L, P<0.05). Along those lines, plasma Cl− was significantly greater in NHE1KS-KO versus control mice at the end of the experimental period (117±1.9 versus 111±0.4 mmol/L, P<0.05). Taken together, our data indicate that NHE1 in principal cells plays an important role in the development of nephrogenic diabetes insipidus as well as the development of hypernatremia and hyperchloremia. This work was supported by a VA Merit Review Award IBX004968A (to Dr. Rieg) and a Pilot Project from the USF Microbiomes Institute (to T.R. and J.D.R). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Caki-1 Spheroids as a 3D Model for Studying Free Fatty Acid-Induced Proximal Tubule Lipotoxicity
Authors: Battle Dana , Qiu Xiangzhe , Alex Marilyn , Rivers London , Zhao Xueying 
Published: May 2024

Three-dimensional (3D) multicellular spheroid shows a biological complexity resembling native tissue in comparison to conventional monolayer cultures, making it a better model system to assess drug effcacy and cytotoxicity. The main aim of this study was to examine the usefulness of Caki-1, a human proximal tubule (PT) representative cell line, as a 3D model system for studying free fatty acid-induced PT lipotoxicity. Caki-1 spheroids were generated and maintained on ultra-low attachment plates and characterized regarding time-dependent changes in morphology and functionality. In optimal 3D culture conditions, Caki-1 cells formed well-defined large compact 3D spheroids with uniform morphology, good circularity, and increased diameter from days 2-10. There was no change when the spheroids were incubated with lipid-free bovine serum albumin (BSA, 0.5%) from day 6 to 10. Chronic exposure to palmitate (300 μM) resulted in dispersed and flattened spheroid morphology, with a larger number of dead cells in the peripheral layers and decreased spheroid core. Moreover, palmitate-treated spheroids showed a significant increase in caspase-3 activity at the external layers of the spheroids, suggesting that the detached cells underwent apoptosis. Simultaneous addition of oleate (200 μM) prevents palmitate-induced spheroid disintegration and cell death in Caki-1 3D culture. Mechanistically, palmitate triggered endoplasmic reticulum (ER) stress and autophagy dysfunction, as evidenced by significantly increased protein levels of ER stress markers AFT4 and CHOP, and autophagy substrate p62. Oleate upregulated adipose differentiation-related protein (ADRP, a lipid droplet-associated protein), and promoted lipid droplet formation in palmitate-treated Caki-1 cells. These results indicate that Caki-1 3D spheroids are a simple and reproducible in vitro system for lipotoxicity study. It can potentially be used for evaluating human renal proximal tubular toxicity and drug screening. NIH/NIGMS R16GM149499, NIH TL1DK136047. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
The use of micro-computed tomography to investigate splenic control of resting oxygen consumption in Tenrec ecaudatus
Authors: Smith Gilbecca Rae , Silva Rubio Claudia , van Breukelen Frank 
Published: May 2024

The canonical functions of the spleen e.g. immune function, blood filtering, and iron recycling overshadow its known role as a blood storage organ in mammals. Boreoeutherians or modern mammals, such as race horses and dogs, experience splenic contractions during exercise where a 30-40% increase in red blood cell availability is associated with an increase in oxygen consumption. Early data (pre-1960) suggest that splenic sequestration may be used in hibernators. Tenrec ecaudatus are basoendothermic mammals that possess numerous ancestral features such as a cloaca. We posit that tenrecs may provide evolutionary insight into the ancestral function of the spleen. Tenrecs may experience as much as a 25-fold variation in resting oxygen consumption as well as a 14-fold variation in spleen size. We contend that sequestration of red blood cells to the spleen in tenrecs controls oxygen consumption. Here, we present data that directly tests the association of spleen size and oxygen consumption using micro-computed tomography. We contend the boreoeutherian functions of the spleen may be a derived condition afforded by a heightened level of endothermy/homeothermy and its associated higher level of homeostasis. National Science Foundation, Department of Education. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.