bluuebunny/crossref_metadata_2025 huggingface dataset:
Kidney Stem Cell Reprogramming Drives Spontaneous Hypertension via Exosomes
Authors: Han Xiaobin , Meyers Rebecca , Kwon Young In , Zhang Bo , Sun Zhongjie
Published: May 2024

The spontaneously hypertensive rat (SHR) is a commonly used animal model for studying primary hypertension. However, the precise mechanism of these rats developing hypertension remains to be defined. Here, we have first demonstrated that kidney stem cell reprogramming is a driver for the development of hypertension in SHR rats. In this study, we treated 5-week-old SHR rats with WKY-kidney stem cell-derived exosomes (WKY-Exo) and 5-week-old WKY rats with SHR-Exo, respectively, via i.p. injections. Notably, WKY-Exo effectively blocked the development of hypertension and arterial stiffening in SHRs. It is fascinating that WKY rats developed hypertension and arterial stiffening due to treatment of SHR-Exo. We confirmed that both WKY- and SHR-Exo were up taken into aortic endothelial and smooth muscle cells after i.p. delivery of CD63/GFP-labelled exosomes. We demonstrated that WKY-Exo can improve vascular functions and arterial compliance of SHR rats as evidenced by preventing the development of arterial stiffness and restoring renal artery endothelial function. We also demonstrated that the vascular functions were impaired in WKY rats after SHR-Exo treatment. Furthermore, our data show that expression of Elastin, Emilin1, and Myh11 was significantly downregulated in the aorta of SHR rats, which can be repaired by WKY-Exo treatment. SHR-Exo decreased expression of Elastin and Emilin1 without affecting Myh11 in the aorta of WKY rats, suggesting that Elastin and Emilin1 deficiency could contribute to arterial stiffening leading to the development of spontaneous hypertension. Proteomic analysis reveals the enrichment of protein-protein interaction network for elastic fiber assembling, blood vessel development, and regulation of angiogenesis in WKY-Exo vs SHR-Exo. In conclusion, our data first demonstrates that kidney stem cell reprograming is a driver for the development of spontaneous hypertension in SHR rats. WKY-KSCs-derived exosome contains a proteome profile promoting arterial repair, which may provide a therapeutic means to prevent and treat primary hypertension.

NIH.

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.
Role of intestinal claudin-2 in calcium transport and kidney stone disease
Authors: Nyimanu Duuamene , Behm Christine , Yu Alan SL
Published: May 2024

Background: Kidney stone disease is characterized by intestinal hyperabsorption of calcium and hypercalciuria, leading to the formation of calcium crystals in the kidney. Claudin-2 is a tight junction protein that forms paracellular cation pores and mutations in its gene are associated with kidney stone disease. We have recently shown that mice deficient in Cldn2 are hypercalciuric due to both decreased renal reabsorption and increased intestinal absorption of calcium and develop medullary mineral deposits reminiscent of kidney stone formers. We, therefore, hypothesized that intestinal claudin-2 is important for calcium secretion, especially in the colon, and that loss of claudin-2 results in increased net intestinal calcium absorption, thereby contributing to kidney stone disease. Method: Villin-Cre (Vil1-Cre/1000Gum) mice were crossed to Cldn2 floxed mice to generate intestine-specific claudin-2 knockout mice. Successful knockout of claudin-2 was confirmed at the mRNA and protein level using qPCR, immunofluorescence staining, and western blot. Male and female littermates were characterized for hypercalciuria from age 3-10 weeks. Circulating levels of parathyroid hormone and 1,25-dihydroxyvitamin D (1,25(OH)2D) were measured by ELISA, and mRNA levels of seven paracellular and transcellular calcium transport genes in the ileum, cecum, distal colon, and nine in the kidney assessed by qPCR. Result: In females, Cldn2 expression was knocked out in the intestine but not in the kidney. However, in males, Cldn2 was knocked out in the intestine and also partially knocked out in the kidneys (where villin is also expressed). Knockout females had normal urine calcium, but knockout males had significantly higher urine calcium at weaning (3 weeks of age) compared to wildtype, which was normalized by 4 weeks of age. At 4 weeks, Cldn19 mRNA was downregulated in knockout mice of both sexes. Male knockout mice had a reduction in intestinal Cldn12, Cldn15, Slc8a1, and increased intestinal Cacnad1, increased renal Cyp27b1 expression, and increased circulating 1,25(OH)2D. Conclusion: Our results suggest that intestine-specific loss of claudin-2, which was only observed in villin-Cre, Cldn2 floxed females, does not cause hypercalciuria. Ongoing whole-body calcium balance and everted sac calcium permeability experiments will determine whether this is because intestinal calcium hyperabsorption is masked by compensatory mechanisms.

NIH.

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.
Concept mapping in an Online Undergraduate Pathology Course: Integrating etiology, pathophysiology, and clinical aspects of disease
Authors: Johnson William
Published: May 2024

Concept mapping has proven to be a useful tool in science education by helping students make connections between facts thereby establishing hierarchies of knowledge. These hierarchies enable students to assimilate information into meaningful reference memories. During the COVID pandemic, classroom activities were severely limited, creating a lack of classroom engagement. Online classes replaced in-class lectures, decreasing opportunities for student contact. To address this pedological shortcoming, concept maps were utilized in an asynchronous online pathology course for pre-health profession undergraduate students. Students asked to create a concept map for a disease, connecting the disease’s pathophysiology, etiology, and clinical considerations. Rough drafts of maps were given feedback to improve connections and flow of the maps. Maps were graded using a rubric modified from several sources, and points were awarded when connections were made within and between the three main pillars of pathology. There were many types of creative maps. Course evaluations indicated that students enjoyed concept mapping as a learning alternative to standard class assignments. The overall goal was to provide a precursor activity that would enhance students’ abilities to utilize algorithms in clinical settings.

No support was required.

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.
Interactions Between Reproductive Hormones and Neuro-Vascular Regulation During the Cold Pressor Test in Young Females
Authors: Coovadia Yasmine , Chaudhry Laila A , Malenda Divine , Van Berkel Emily K. , Usselman Charlotte W.
Published: May 2024

Recently, we reported that muscle sympathetic nerve activity (MSNA) is not predictive of vascular nor blood pressure outcomes during the cold pressor test (CPT) in young healthy females. Instead, we observed substantial variability in vascular responses to the CPT which ranged widely from decreases in blood flow and vascular conductance to increases in these same outcomes. Interindividual differences in circulating reproductive hormones may account for this female-specific variability in vascular responses to acute elevations in MSNA. Therefore, the purpose of this study was to test the hypothesis that reproductive hormones account for variability in MSNA, femoral blood flow (FBF), and femoral vascular conductance (FVC) during the CPT in females. We retrospectively assessed data from 9 young healthy females (age: 24±3 years) in the low hormone phase of their menstrual cycle (days 1-5). Intravenous blood samples were obtained and prospectively analyzed to assess concentrations of circulating reproductive hormones (radioimmunoassay). Integrated peroneal MSNA (microneurography; NeuroAmpEX, ADI) was quantified at rest and during a 3-minute hand CPT. Mean arterial pressure (MAP) was measured beat-by-beat (Finometer Midi, FMS) and duplex vascular ultrasound was used to measure FBF; FVC was quantified as FBF/MAP (mL/min/mmHg). All variables are expressed as the difference between the average CPT value and the average baseline value. CPT-induced changes in MSNA burst incidence (bursts/100hb) were not related to [17-beta-estradiol] (R2=0.05; P=0.60), [progesterone] (R2=0.11, P=0.47), or [free testosterone] (R2=0.01, P=0.81). Similarly, changes in FBF and FVC were not related to [17-beta-estradiol] (FBF: R2=0.04, P=0.67; FVC: R2=0.01, P=0.80) or [progesterone] (FBF: R2=0.04, P=0.67; FVC: R2=0.09, P=0.51). However, there was a negative correlation between [free testosterone] and the changes in both FBF (R2=0.69, P=0.02) and FVC (R2=0.66, P=0.03). In other words, females with higher free testosterone demonstrated larger decreases in FBF and FVC during the CPT relative to those with lower free testosterone concentrations. These data suggest that circulating free testosterone may act to increase the vasoconstrictive consequences of MSNA in females, and may account for the previously observed variability in vascular responses to MSNA during acute stress.

This project was funded by: NSERC and FRQ-S.

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.
Role of Angiotensin II on Cardiovascular/Autonomic Function and Cognition in a Novel Mouse Model of Alzheimer’s Disease
Authors: Shahab Nusaira Beenta , Smith Cassandra N. , Cerri Gabriela C. , Weiss Robert M. , Zimmerman Kathy , Yang Liping , Sabharwal Rasna
Published: May 2024

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder. Despite being the most common form of dementia in the elderly, mechanisms causing AD remain elusive. Emerging evidence have associated brain renin-angiotensin system (RAS) to AD neuropathology. RAS actions are predominantly mediated by angiotensin II (Ang II) binding to type 1 receptors. Previously, we have observed that human apolipoprotein E4-knockin (risk factor for AD) mice develop progressive hypertension and increases in Ang II levels in CSF with aging [FASEB J 36(S1): R3532]. Thus, we hypothesize that Ang II-mediated hypertension contributes to cognitive decline in AD. We have generated a novel transgenic mouse model of AD i.e. 3XE4 by breeding E4-knockin mouse with APPsw, PS1dE9, and tauP301S transgenes, to mimic human AD pathology in mice. Blood pressure (BP) and heart rate (HR) were measured by radiotelemetry in 3XE4 (n=6) and control 3XE3 (n=6) mice, before and after 28-days of Ang II infusion (1000 ng/kg/min, osmotic pump). Diurnal BP variability was calculated as the difference between night-time (11:00 PM-3:00 AM) and day-time (8:00 AM-12:00 PM). Cardiac vagal and sympathetic tones were calculated as changes in HR with atropine and propranolol (1 mg/kg each, IP), respectively. Cardiac function (echocardiography) and cognitive behavior (novel object recognition test) were measured. At baseline, BP was similar in control (127±11 mmHg) and 3XE4 (123±5 mmHg) mice. Unlike the control mice, 3XE4 mice exhibit reduced vagal tone (ΔHR= +119±22 vs. +25±24 bpm) and increased sympathetic tone (ΔHR= -76±33 vs. -212±40 bpm), which worsens with Ang II (p<0.05 vs. baseline). Interestingly, Ang II increased BP (24%), induced LV hypertrophy (26%), impaired diurnal BP variability, and evoked learning and memory deficits; albeit only in the 3XE4 mice (p<0.05 vs. control mice). These results demonstrate that Ang II-mediated hypertension and autonomic dysfunction likely exacerbate disease progression and cognitive decline in the 3XE4 mouse model of AD. Therefore, our study provides a proof-of- concept in delineating the association of ApoE4 genotype and Ang II with Alzheimer’s disease.

NIH R01HL149677 and R21AG070188.

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.
Orexin 1 Receptors in The Paraventricular Nucleus of The Hypothalamus (PVN) Facilitate The Peripheral Chemoreflex
Authors: Ben Musa Ruwaida , Li De-Pei , Kline David D , Hasser Eileen M , Cummings Kevin
Published: May 2024

Increased sensitivity of the peripheral chemoreflex (PCR) to hypoxia is associated with cardiovascular-related diseases such as hypertension and heart failure. We previously showed that systemic blockade of both orexin 1 (Ox1R) and orexin 2 receptors reduced the PCR-mediated hypoxic ventilatory response (HVR), and that hypoxia activates PVN-projecting orexin neurons. The effect of OxR blockade on the HVR was strongest in the active phase of the circadian cycle and was associated with decreased numbers of activated neurons in the nucleus of the solitary tract (nTS) and nTS-projecting corticotropin-releasing neurons in the PVN. While the projection from the PVN to the nTS contributes to the PCR, the neuronal mechanism(s) activating this projection are unclear. We hypothesized that orexin acting at Ox1R in the PVN facilitates the PCR. To test this hypothesis, we first performed IHC to confirm the expression of Ox1R in the PVN. We then assessed the degree to which specific Ox1R blockade reduced the HVR (n=6; tested first with vehicle (100% DMSO), then Ox1R antagonist SB-334867, 1 mg/kg, i.p). To assess the contribution of PVN Ox1Rs to the PCR as well as the associated activation of neurons in the PVN and nTS, we specifically knocked down Ox1R expression in the PVN via nanoinjection of an Ox1R shRNA-GFP expressing AAV vector. Rats were exposed to graded hypoxia during the active phase, with inspired O2 taken from 21% to 11% over a ~5 min period. Rats were kept near-isocapnic by slightly increasing the inspired CO2. Subsets of rats were exposed to hypoxia to assess the effects of Ox1R on neuronal activation using c-Fos expression as a surrogate marker. Systemic Ox1R blockade significantly reduced the HVR compared to the control response (by ~30%; p=0.0027). Knockdown of Ox1R in the PVN also reduced the HVR (by ~20%; p=0.049) and reduced the number of c-Fos expressing PVN neurons in response to hypoxia (p=0.0232). More specifically, hypoxia induced c-Fos expression in fewer PVN neurons transfected with Ox1R shRNA (confirmed by GFP expression) than neurons from control rats transfected with scrambled RNA (p=0.0083). Ox1R knockdown in the PVN also significantly reduced the hypoxia-induced increase in number of c-Fos expressing tyrosine-hydroxylase (TH) nTS neurons (p=0.0303), suggesting that PVN Ox1Rs mediate hypoxia-induced activation of TH neurons in the nTS. These findings suggest that in the PVN, orexin acting at Ox1Rs mediate the facilitation of the PCR and the associated activation of the PVN and nTS neurons. Ox1R in the PVN could be a novel target to treat diseases associated with increased PCR sensitivity.

Grants: 5R01HL098602 (to DK, EH and KC).

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.
Unraveling the evolutionary marathon: improved mitochondrial bioenergetics in CMP-Neu5Ac hydroxylase gene deleted (Cmah−/−) mouse skeletal myofibers
Authors: Al Dikka Donivian , Breen Ellen , Nogueira Leonardo
Published: May 2024

Objective: Humans are unique among hominids in that they are endurance athletes. Inactivation of the CMP-Neu5Ac hydroxylase (CMAH) gene, which encodes a hydroxylase converting sialic acid Neu5Ac to Neu5Gc, is thought to contribute to this exceptional capacity for endurance running. Recently, our group demonstrated improved fatigue resistance and preserved intracellular O2, estimated by NAD(P)H levels in contracting mouse Cmah−/− flexor digitorum brevis (FDB) single fibers under low oxygen tension. Hypothesis: Effcient regulation of mitochondrial oxygen consumption contributes to improved skeletal myofiber fatigue resistance in Cmah−/− mice. Methods: The mitochondrial bioenergetic potential of permeabilized FDB and soleus fiber bundles from wild type (WT) and Cmah−/− mice was evaluated using a physiological creatine kinase clamp method and high-resolution respirometer. Experiments were conducted with pyruvate and malate with or without branched chain amino acids (BCAAs) as the substrates. Respiratory chain conductance and maximal respiration were measured. Results: FDB Cmah−/− fibers from male but not female mice revealed an increase conductance above WT fibers independent of substrate (male: genotype, p=0.006, substrate, ns; female: genotype, ns, substrate, ns). Maximal respiration was also increased only in male FDBs fibers and was even greater when BCAAs were included in the respiration media. (male: genotype, p=0.003, substrate, p=0.0007, interaction, p=0.002.; female: genotype, ns, substrate, ns). Soleus Cmah−/− fibers from male and female mice revealed an increase conductance above WT fiber bundles that was also greater in the presence of BCAAs but only for male mice (male: genotype, p=0.003, substrate, p=0.05.; female: genotype, p=0.009, substrate, ns). Maximal respiration was increased only in male Cmah−/− soleus fibers independent of substrate. (male: genotype, p=0.002, substrate, ns.; female: genotype, ns, substrate, ns). Summary: Fibers from both the FDB and soleus of male Cmah−/− mice have a greater capacity for mitochondrial respiration under a metabolically active state that is similar to myofibers stimulated to repeatedly contraction in a hypoxic environment. Conclusion: These data suggest that effcient regulation of mitochondrial respiration utilizing BCAAs as a substrate, particularly in males, could contribute to an elite endurance phenotype.

This project was funded through the UC San Diego Academic Senate Grant.

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.
Temporal Effects of Safflower Oil Diet-based Linoleic Acid Supplementation on Barth Syndrome Cardiomyopathy
Authors: Zhu Siting , Pang Jing , Nguyen Anh , Tan Changming , Tso Alexandria , Huynh Tiana , Gu Yusu
Published: May 2024

Background: Barth syndrome (BTHS) is an X-linked mitochondrial lipid disorder caused by mutations in TAFAZZIN ( TAZ). Cardiomyopathy is a major clinical feature in BTHS. Thus far, there is no curative therapy for BTHS. TAZ is an acyltransferase required for remodeling/maturation of cardiolipin (CL), a signature phospholipid of mitochondria. TAZ deficiency causes ineffcient transacylation and maturation of CL. In mammalian heart, the major mature CL species is tetralinoleoyl-CL, containing four linoleic acid (LA) side chains. LA is one of two essential fatty acids that must be obtained through diet. In this study, focus on the investigation of potential therapeutic effects of a safflower oil diet-based LA supplementation on BTHS cardiomyopathy. Hypothesis: Linoleic acid (LA) supplementation could ameliorate BTHS by increasing incorporation of linoleoyl groups into nascent CL towards mature CL composition without requiring the remodeling process. Methods: Taz global (gKO) and cardiomyocyte-specific knockout (cKO) mouse models were fed with high-LA safflower oil diet (LAD) contained 10% LA (LA weight/chow weight; law/cw) and the low-LA palm oil control diet (CD) contained 1% LA (law/cw). Echocardiographic analysis was performed for cardiac function over a full-time course. Lipidomic analysis was performed to determine CL profiles in mutant hearts. Results: Our results clearly revealed that dietary LA supplementation fully prevented cardiomyopathy in Taz gKO and cKO mutants at 4 months of age, with cardiac function of mutants in the LAD group being comparable to that of WT controls, while mutants in the CD group displayed significant dilated cardiomyopathy (DCM) at this age. The beneficial effects of LA supplementation extended to, albeit with diminishing effcacy, at 6 and 8 months of age. In lipidomic analysis, we observed “BTHS-like” CL profiles in Taz cKO hearts both in LAD and CD groups. However, LAD ameliorated the severity of CL abnormalities in Taz cKO hearts. Interesting, beneficial effects of LAD on CL profiles declined at 8 months of age. Conclusion: Our study demonstrated that dietary LA supplementation has potential to delay development of BTHS cardiomyopathy at early stages, but there is a declining effectiveness as the disease progresses, providing important insights into the temporal effects of LA in BTHS therapy.

Xi Fang is supported by NIH grants. Sylvia M Evans is supported by NIH grants and the Foundation Leducq (16 CVD 03). Asa B Gustafsson is supported by NIH grants R01HL155281 and R01HL157265.

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.
Red Blood Cell Hemoglobin Oxygen Transfer in Deep-Diving Marine Mammals
Authors: Duong Marie , Suprapto James , Breen Ellen , Tift Michael , Jennings Patricia , Tong William
Published: May 2024

Objective: Some marine mammals of the order pinniped and cetacean can dive for long durations to forage for food and travel over distances. During these extended dives both pinnipeds and cetaceans experience extreme tissue hypoxia. Numerous adaptations have evolved to allow these species to effciently deliver and utilize oxygen (O2). One genetic difference, which our laboratory has proposed to play an important role in O2 transport effciency in modern hominids, is the inactivation of the CMP-Neu5AC hydroxylase (CMAH) gene. Pinnipeds inactivated Cmah ~ 40 million years ago but, cetaceans still express this N-glycan modifying enzyme. CMAH converts the sialic acid, N-acetylneuraminic acid (Neu5Ac), to its hydroxylated form, N-glycolylneuraminic acid (Neu5Gc). These sialic acids are located at the end of branched sugar chains on the surface of cell membranes. As a result, a change in composition could affect cell membrane charge and hydrophobicity, as well as potentially alter O2 diffusion laterally or across cell membranes. Hypothesis: In this study we hypothesized that O2 transfer from hemoglobin (Hb) in red blood cells (RBCs) to myoglobin (Mb) would differ between cetaceans (CMAH+) and pinnipeds (CMAH-). Methods: This hypothesis was tested using optical absorption spectroscopy to measure O2 exchange between oxygenated Hb in RBC and deoxygenated Mb collected in several species of mustelids and pinniped (CA sea otter, CA sea lion, and walrus) and cetaceans (Bottlenose Dolphin, Beluga, and Orca). Measurements of cell diameters (diffusion length) were also measured. Results: The mean oxygen transfer (O2D/A410) was 47% lower in pinnipeds than cetaceans (p<0.01). The amount of O2 transferred in cetaceans increased with longer reported maximal dive durations. There was a trend for overall RBC diameters to be larger in cetaceans than pinnipeds (p=0.054). Summary: The RBC O2 transfer data in these hypoxia tolerant marine mammals suggest a transfer mechanism that is more effcient in cetaceans in a normoxic environment. Conclusions: More effcient oxygen transfer in cetaceans, who retained the Cmah gene, compared to pinnipeds and mustelids, who did not retain the Cmah gene, suggests that the gene knockout may not be the only factor that facilitates delivery of O2 in these marine mammals. A trend for larger RBC diameters in cetaceans than pinnipeds also suggests that diffusion length is not a main contributing factor. Future experiments to measure oxygen transfer from RBC O2-Hb to Mb under different O2 environments are needed to more closely model what may occur during long duration dives.

NSF1929325.

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.
Gold nanoparticles-conjugation of irisin enhances therapeutic effect by improving cardiac function and attenuating inflammation in sepsis
Authors: Wang Lijiang , Kulthinee Supaporn , zhao Yu , Yano Nahiro , zhang Ling , Wen Huai , Zhao Ting
Published: May 2024

Introduction: Irisin is considered to be a promising therapeutic approach for cardiac depression and inflammatory disorders. The short half-life of irisin impeded its use and drug effcacy in the treatment. Objective: This study aimed to examine if pegylated gold nanoparticles-conjugated to irisin would improve therapeutic effects in cecal ligation and puncture (CLP)-induced sepsis in mice. Method: Recombinant irisin were conjugated to a pegylated gold nanoparticle, which was given to mice exposed to CLP. The cecal ligation procedure and sham on mice were operated and assigned to one of following five groups: I) CLP group: The mouse models underwent the CLP surgical procedure and received only vehicle saline treatment (n= 5); II) CLP + soluble Irisin: The mouse underwent the CLP and received an i.m (TA) injection of 1 ug of soluble irisin into each leg (n= 5); III) CLP + Gold nanoparticle-conjugated to Irisin: The mouse models underwent the CLP and received an i.m (TA) injection of 1 μg of Gold nanoparticle-irisin via intramuscular injection (TA) into each leg w (n= 5); IV) CLP + Gold nanoparticles- conjugated to IgG: The mouse underwent the CLP and received an i.m (TA) injection of gold nanoparticles conjugated to IgG (n=5). V) Sham: The mouse underwent the surgical operation without conducting the CLP (n=10). The post-operated animals were observed for one week, and survival rates were estimated. Echocardiography was performed to measure cardiac function at 12 hours following CLP. TUNEL was employed to detect apoptosis in both cardiac and skeletal muscles; histology was conducted to assess tissue injury in muscles. Enzyme linked immunosorbent assay (ELISA) was conducted to examine release of interleukin 6 (IL6) and the tumor necrosis factor (TNF) alpha. Results: Compared to the CLP control, soluble irisin treatment improved cardiac function recovery, as indicated by the fractional shortening (FS) and ejection fraction (EF). Irisin treatment exhibited reduced IL6 and TNF-alpha release in association with less apoptosis, lower muscle injury index and improved survival post-CLP. However, compared to soluble irisin treatment, gold nanoparticles-conjugated to irisin showed a significant improvement in cardiac function, suppression of apoptosis, reduced IL6 and TNF-alpha releases, decreased muscle injury and an improved survival rate of post-CLP. Conclusion: This study reveals that gold nanoparticles-conjugated irisin can serve to improve irisin’s therapeutic effects over a longer course of treatment.

National Institute of General MedicalSciences (R01GM 141339); National Heart, Lung, andBlood Institute Grants (R01 HL089405).

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.
Meeting the Needs of Underrepresented Female Students Using Innovative Molecular Models
Authors: Lester King Adrienne , de la Cruz Jennifer , Johnson Cassandra
Published: May 2024

The underrepresentation of women in science, technology, engineering, and math (STEM) fields is of national concern. Research shows that females begin to lose confidence in their math and science abilities in middle school and it worsens in high school. Developing and leveraging young women’s interest in these topics via active learning activities and hands on models can encourage pursuit of STEM degrees in college. The MIT Edgerton Center Models and Curriculum was incorporated into the EMPOWER Program, a four-week program engaging female research scholars in 10th-12th grade in a summer fellowship that provided hands-on research experience focused on in-depth understanding of how exposures to toxic environmental insults in the urban environment impact health and alter biologic processes. The models were used to teach about DNA/RNA and protein synthesis. The models are designed to teach processes, in addition to structure. They are made to be manipulated so learners can perform cellular functions with their own hands. We hypothesized that using a hands on activity would increase engagement and learning about the Central Dogma of Life. Methods: Participants were guided through exercises using the models. Students (n=5) and teachers (n=2) utilized the MIT Edgerton Center Models of DNA/RNA and protein synthesis. Results/Discussion: Surveys were completed at the end of the program to determine student’s perceived impact on their learning and overall experience using the hands-on models. A Likert scale was used to assess student learning. On a scale of 1 to 5, with 5 representing strongly agree, all participants strongly agreed the models helped them learn more about DNA/RNA and proteins. Conclusion: Innovative molecular models increased student engagement and learning creating an environment for student centered learning.

NIEHS Project Number: 5R25ES030240-03.

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 impact of a single high-fat meal on indices of cerebrovascular function & health
Authors: Perry Ken A. , Ortiz Alison , Kolade John O. , Shah Prarthi J. , Patik Jordan C. , Brothers R. Matthew
Published: May 2024

High-fat diets contribute to elevated risk for cardiovascular, cerebrovascular, metabolic, and neurocognitive diseases with reduced vascular health being a contributing factor. It is well documented that a single high-fat meal (HFM) reduces peripheral vascular function. Despite the elevated risk for/prevalence of cerebrovascular and neurocognitive disease with a high-fat diet, the impact of a single HFM on cerebrovascular function/health is less known. Cerebrovascular pulsatility index (PI) (measure of cerebral vascular stiffness) and cerebral autoregulation (ability of the cerebral vasculature to maintain constant blood flow during changes in arterial blood pressure) are indices of cerebral vascular function/health that are impaired in populations with elevated disease risk. To our knowledge, the impact of a HFM on these indices have not been studied. Accordingly, this study tested the hypothesis that a single HFM will blunt cerebrovascular function/health as indexed by increased PI and transfer function gain. Methods: Fifteen individuals (13 male; age: 28±11yr; BMI: 24±4 kg/m²) participated. Measures were made before and 2hr post-consumption of a HFM (990 kcal, 55g fat, 89g CHO, 35 g protein, 2120 mg sodium) which was purchased from McDonald’s. The HFM consisted of the following: 1 Sausage Biscuit, 1 Egg McMuffn, 2 hash browns, and 1 bottle of water. Continuous measures of beat-to-beat blood pressure and middle cerebral artery blood velocity (MCAV) were obtained during a minimum of 6-min quiet supine rest. Pulsatility index (measure of cerebrovascular stiffness) was calculated as MCAVsystolic − MCAVdiastolic / MCAVmean. Cerebral autoregulation was calculated as transfer function gain between spontaneous beat-to-beat changes in mean blood pressure and MCAVmean. Results: Cerebrovascular stiffness (PI) was increased following the HFM (pre: 0.81±0.12, post: 0.92±0.15; p<0.001). Cerebrovascular autoregulation indexed as transfer function gain was elevated following the HFM in the very low, low, and high frequency ranges ( p=0.01 for all). Pulsatility index and transfer function gain were correlated in the low frequency range before (R=0.77, p<0.01) and after (R=0.64, p=0.02) the HFM. Conclusion: These preliminary data indicate that a single HFM reduces indices of cerebral vascular function/health. Lastly, there is a positive relationship between PI and transfer function gain. Future work will continue to build upon these findings in a larger data set and will consider the impact of long-term exposure to a traditional HFM diet.

Funding: The University of Texas at Arlington College of Nursing and Health Innovation and Institutional Start up Funds to Dr. Brothers.

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.
AGPAT3 deficiency impairs adipocyte differentiation and leads to a lean phenotype in mice
Authors: Zhou Hongyi , Chen Weiqin
Published: May 2024

Acylglycerophosphate acyltransferases (AGPATs) catalyze the de novo formation of phosphatidic acid to synthesize glycerophospholipids and triglycerides. AGPATs demonstrate unique physiological roles despite a similar biochemical function. AGPAT3 is highly expressed in the testis, kidney, and liver, with intermediate expression in adipose tissue. Loss of Agpat3 is associated with reproductive abnormalities and visual dysfunction. However, the role of AGPAT3 in adipose tissue and whole-body metabolism has not been investigated. We found that male Agpat3-KO mice exhibited reduced body weights with decreased white and brown adipose tissue mass. Such changes were less pronounced in the female Agpat3-KO mice. Agpat3-KO mice have reduced plasma insulin growth factor 1 (IGF1) and insulin levels and diminished circulating lipid metabolites. They manifested intact glucose homeostasis and insulin sensitivity despite a lean phenotype. Agpat3-KO mice maintained an energy balance with normal food intake, energy expenditure, and physical activity, except for increased water intake. Their adaptive thermogenesis was also normal despite reduced brown adipose mass and triglyceride content. Mechanistically, Agpat3 was elevated during mouse and human adipogenesis and enriched in adipocytes. Agpat3-knockdown 3T3-L1 cells and Agpat3-deficient mouse embryonic fibroblasts (MEFs) have impaired adipogenesis in vitro. Interestingly, pioglitazone treatment rescued the adipogenic deficiency in Agpat3 deficient cells. We conclude that AGPAT3 regulates adipogenesis and adipose development. It is possible that adipogenic impairment in Agpat3 deficient cells potentially leads to reduced adipose mass. Findings from this work support the unique role of AGPAT3 in adipose tissue.

This work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases [1R56 DK135657] and the National Heart, Lung and Blood Institute [2R01HL132182-01] to W.C.

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.
Effects of At-Risk Drinking on Ambulatory Blood Pressure in Young Adults
Authors: Pham Jonathan , Chang Keng-Yu , Haun Tabitha , Truong Preston , Gil Alfredo , Phan Kelly , Liu Zhaoli
Published: May 2024

Introduction: At-risk drinking is associated with an increased risk of cardiovascular diseases (CVD) even in young adults. However, this association is mainly based on offce blood pressure (BP) measurement. Ambulatory BP monitoring captures diurnal variation in BP and is a more sensitive CVD predictor than offce BP. Therefore, the purpose of this study is to investigate the effects of at-risk drinking on ambulatory BP in young healthy adults with normal offce BP. Method: A total of 20 healthy men and women (21-35 years), non-smokers, were included in this cross-sectional study. All participants had an offce BP lower than 130/80 mmHg. Using the US Alcohol Use Disorders Identification Test (USAUDIT), at-risk drinkers were defined as those having a total USAUDIT score higher than 7 for men (6 for women). All participants underwent 24-hour ambulatory BP monitoring (Oscar 2™, SunTech Medical®). To investigate the vascular mechanisms underlying the effects of at-risk drinking on ambulatory blood pressure, aortic arterial stiffness and wave reflection were measured as pulse wave velocity (PWV) and augmentation index (AIx) by using SphygmoCor XCEL system (AtCor Medical). Results: No differences were found in age and BMI between at-risk drinkers (n=10) vs. low-risk drinkers (n=10; mean ± SD for age: 26.7 ± 3.7 vs. 26.6 ± 4.3 years, P>0.99 and BMI: 24.5 ± 2.4 vs. 23.8 ± 2.9 kg/m2, P=0.6). At-risk drinkers had a higher total USAUDIT score (10.6 ± 2.7 vs. 1.4 ± 1.2, p<0.001). While there was no difference between at-risk drinkers and low-risk drinkers in 24-hour, daytime, and nighttime systolic and diastolic BP (P≥0.5), at-risk drinkers had a higher blood pressure morning surge compared to low-risk drinkers (systolic: 34 ± 10 vs. 22 ± 6 mmHg, P=0.014 and diastolic: 29 ± 9 vs. 15 ± 4 mmHg, P=0.002). No significant difference was found in PWV (5.7 ± 0.6 Vs. 5.5 ± 0.7 m/sec, P=0.4) and AIx (8 ± 8 Vs. 15 ± 11, P=0.1). Conclusion: Our results indicate that despite similar offce BP, young adult at-risk drinkers had higher BP morning surge, an independent risk factor for cardiovascular events, than low-risk drinkers. These findings provide implications in using USAUDIT and out-of-offce BP measurements for cardiovascular disease risk assessment.

This work was supported by NIAAA AA028537 to CLH.

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.
TRIM Enhances Angiogenesis in Dystrophic Muscle 140 Days Post Treatment
Authors: Naman Alexandra , Kendra Jacob , Brow Richard , Segal Steven , Morton Aaron
Published: May 2024

Background: Duchenne Muscular Dystrophy (DMD) causes limb muscle dysfunction and impaired mobility while promoting ischemia in effected muscles. For treatment, we developed a novel biomaterial, Time Release Ion Matrix (TRIM), that promotes angiogenesis and enhances muscle structure and function in dystrophic (D2. mdx) mice at 14- and 70-days post injection (dpi). Whether TRIM remains effective at 140 dpi is unknown. Hypothesis: At 140 dpi in D2. mdx mice TRIM will: 1) enhance isometric force and myofiber cross-sectional area (CSA) of the tibialis anterior (TA) muscle; and 2) stimulate angiogenic growth factors and increase vascularity. Methods: The right and left TA of adult male D2. mdx mice (male, n=7-8, age 7 months) were injected with saline alone (control) or 250 μg of TRIM suspended in saline. At 140 dpi, the left TA muscle was isolated for in situ muscle force measurements and histological analysis; the right TA was frozen for biochemical analysis. Muscle cross-sections were immunostained for laminin (myofiber borders), DAPI (nuclei), and CD31 (endothelial cells). Vascular endothelial growth factor (VEGF) ELISA and immunoblots were performed on muscle homogenates. Results: No difference in peak isometric force was recorded between groups at 140 dpi (means ± SE: TRIM, 65.4 ± 2.7g; Saline, 62.7 ± 1.5g; P= 0.34). TRIM enhanced the relative frequency of myofibers >1000 μm2 by 27% vs. saline (TRIM, 56 ± 2%; Saline, 44 ± 3%; P= 0.006). DAPI staining revealed a 36% increase in central nuclei indicating myofiber regeneration (TRIM, 30.0 ± 1.7%; Saline, 22.0% ± 2.5; P=0.02). Microvessel area (CD31 staining, μm2) was 2.5-fold greater in treated TA’s (TRIM, 131 ± 12 μm2; Saline, 53 ± 6 μm2, P=0.0001). In muscle homogenates, TRIM had no effect on [VEGF] (TRIM, 102 ± 5%; Saline, 100 ± 4%; P= 0.79), while STAT3 activation was greater (TRIM, 129 ± 11%; Saline, 100 ± 7%; P= 0.04). Conclusion: At 140 days following injection of TRIM into the TA muscle of dystrophic mice, peak isometric force was unchanged while myofiber CSA was enhanced. Furthermore, TRIM promotes angiogenic growth factors and muscle vascularity, which should promote the ability to sustain physical activity.

University of Missouri Coulter Biomedical Accelerator (SSS), American Physiological Society SURF (AGN), Texas A&M Department of Kinesiology and Sport Management (ABM).

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.
Flipped Team-based Learning as Universal Design for Learning Physiology
Authors: Terson de Paleville Daniela
Published: May 2024

Universal Design for Learning (UDL) is an educational framework to guide the design of learning environments that are both accessible and challenging. The UDL follows three principles: Multiple means of engagement, multiple means of representation, multiple means of action and expression Lessons plan using UDL anticipates various learning styles, different interests, academic backgrounds, disability status, age, gender, race, and ethnicity. Constructivism is a learner-centered theory of learning in which the instructor is considered a facilitator. In social constructivism, learning is facilitated through interactions with peers and instructors who can guide and support learning. Team-based learning (TBL) is an example of social constructivism. In this session, participants will learn how to implement the various stages of TBL for Biomedical Sciences that could be easily translated into other disciplines. Michelsen & Sweet introduced the essential elements of TBL as a guide for instructors to implement this approach in higher education courses. The main goal of TBL is "ensuring that students have the opportunity to practice course concepts to solve a problem." The model presented by Michelsen consists of 5-7 learning modules that follow three-step cycles: 1) preparation step (pre-class). This step was created as "flipped" classroom with a variety of learning methods, assessments and virtual labs with immediate feedback to facilitate preparedness for step two 2) Step two is class readiness assurance; in this step, students take a two-step quiz process. First, students complete a quiz individually and submit their answers in scantron form. Subsequently, students re-take the quiz using the Immediate Feedback Assessment Technique (IF-AT) as a team. Afterwards, students can challenge any questions they may have missed. Then, the instructor spends the last 10-15 minutes of the class for a short lecture to clarify misconceptions and review the questions. The readiness assurance portion lasts between 45-75 minutes. Finally, 3) step 3 is called "Application of Course Concepts," in which application assignments are given to the teams. This period takes 1-4 hours, and thus, the most significant component of TBL is application. We hypothesize that flipped TBL can be effectively used as a UDL for undergraduate and graduate physiology courses. Undergraduate and graduate students report better understanding of concepts, engagement, and inclusion after participating on a TBL course. Conclusion: Flipped TBL is a powerful and effective teaching strategy to create an inclusive environment in physiology courses.

APS Teaching Career Enhancement Award and University of Louisville Department of Physiology.

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.
Mitochondria Regulate Spatiotemporal Ca2+ Dynamics Between Cellular Compartments Affecting the Intrinsic Excitability of Vasopressin Neurons
Authors: Kirchner Matthew , Stern Javier
Published: May 2024

Calcium (Ca2+) is a critical secondary messenger in all neurons that coordinates important mechanisms of cell physiology. In vasopressin (VP) neurons of supraoptic nucleus (SON) it’s required for somatodendritic release of VP and the slow afterhyperpolarization (sAHP), both of which coordinate neuronal output and thus control stimulus-secretion coupling. Recently, our lab demonstrated that VP sAHPs require endoplasmic reticulum (ER) Ca2+ for activation and that mitochondrial Ca2+ buffering shapes the spatiotemporal trajectory. We also have recent data demonstrating electrotonic segregation between cell compartments. Given the Ca2+ dependence of somatodendritic release and sAHPs, delineation of somatodendritic release from axonal release, and the decoupling of somatic and dendritic electrontonic properties, we hypothesized that calcium dynamics also may be compartmentally segregated as well. Utilizing patch clamp electrophysiology, live calcium imaging, and focal UV uncaging, we probed the spatiotemporal trajectory of rapidly evoked Ca2+ responses in VP neuron somas and dendrites with corresponding membrane potential. UV Ca2+ uncaging at the soma evokes a membrane sAHP and robust increase in cytosolic Ca2+ that propagates into the dendrites. Conversely, Ca2+ uncaged in dendrites propagates bidirectionally from the UV flash but does not penetrate the soma; no membrane hyperpolarization was observed under these conditions. Disabling mitochondrial Ca2+ buffering with Ru360 in the pipette amplifies Ca2+ signasl and sAHPs in somas and dendrites; Ca2+ uncaging in dendrites penetrates soma and can evoke sAHPs under these circumstances. Together, these results suggest that under normal conditions, Ca2+ movement between compartments in VP neurons is unidirectional (soma to dendrite), and that sAHP channels require somatic Ca2+ increases. Moreover, Ca2+ uptake by mitochondria is a critical mechanism that tightly controls the magnitude and progagation of dendritic Ca2+ signals between dendritic and somatic compartments, thus playing an important role in regulating intrinsic mechanisms and ultimately, their neuronal output.

NIH K99HL168434 (M.K.K.); R01 HL162575-01 (J.E.S.).

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.