Animal Care Research Articles

Veterinary students’ attitudes toward anesthesiology as a specialty

ObjectiveTo identify the perceptions of veterinary students interested in specialization regarding veterinary anesthesiology. Study designCross-sectional, multi-institutional, voluntary, anonymous, nonrandomized survey. PopulationVeterinary students (303 of 557 total respondents) from 10 veterinary schools. MethodsQuantitative data were obtained via 5-point Likert scale questions about anesthesia-related topics. Open-ended questions were used to obtain qualitative data. A multivariate logistic regression model assessed the likelihood of choosing a career as an anesthesiologist. Spearman’s rank correlation coefficient was used to assess the relationship between ‘anesthesia is interesting’ and other variables. ResultsOf the respondents, 14 (6%) indicated veterinary anesthesia as their chosen specialty. There was a significant positive relationship between ‘anesthesia is interesting’ and the following variables: age, enjoyment in anesthesia class, belief in the importance of anesthesia for their career, belief in the importance of analgesia for their career, belief that anesthesia and analgesia have a large impact on patient care, interest in pharmacology, interest in physiology, interest in learning technical skills, belief that anesthesiologists are respected by their colleagues and belief that anesthesiologists are an important part of the health care team. More weeks on the anesthesia clinical rotation was positively and significantly associated with increased rotation enjoyment. Enjoyment in the anesthesia class [p = 0.001, Exp(β) = 2.1, 95% confidence interval (CI): 1.3–3.4] and belief that anesthesia is interesting [p = 0.013, Exp(β) = 2.6, 95% CI: 1.2–5.4] were predictors that respondents would be more likely to consider a career as a veterinary anesthesiologist. ConclusionsThose veterinary students with an interest in pharmacology and who enjoyed their anesthesia course were more likely to consider a career as a veterinary anesthesiologist. If students indicated no interest in specializing in veterinary anesthesia, they appreciated the value the specialty brings to animal care and believed that veterinary anesthesiologists are respected by their peers.

Role of miRNAs regulation of Orai1 and store operated Ca2+ entry in vascular restenosis

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Agencia Estatal de Investigación Background The main cause of restenosis is attributed to the excessive proliferation and migration of vascular smooth muscle cells (VSMCs). Orai1 is one of the main molecular components of Store-Operated Calcium Entry (SOCE), playing a key role in VSMCs proliferation during neointima formation and vascular remodeling. Recent studies have demonstrated the implication of microRNAs (miRNAs) in VSMCs proliferation and migration, however, the role of these miRNAs as regulators of SOCE during vascular remodeling has not been described. Purpose This study aims to determine whether miRNAs regulate the intracellular Ca2+ handling, focusing on SOCE, during neointima formation. Methods Experiments were conducted in an animal rat model following the "Principles of laboratory animal care" and according to the Spanish law. The neointima development was assessed after balloon injury of carotid arteries and confirmed by haematoxylin and eosin staining, and αSMA staining of tissue sections up to 3 weeks after surgery. miRNAs array and RT-qPCR was used to examine the expression of miRNAs. Dual-Luciferase reporter assay was performed in A7R5 VSMCs line. Results Injured arteries showed significant increase in the expression of Orai1, as compared to non-injured arteries, indicating their possible participation in the neointima layer formation. Microarray of miRNAs analysis of the injured carotids compared to control carotids showed significant increase in the expression of miRNAs related to signalling pathways involving cell proliferation and migration, cell differentiation, or VSMCs contraction. Of these, we confirmed the significant increase of miR-18a-5p, miR-20a-5p, miR-20b-5p and miR-17-5p, which belong to widely studied miR-17-92 cluster involved in different cell proliferation. Moreover, we found that mimics of those miRNAs were able to regulate differentially the activity of the Orai1 promotor in A7R5 cell line, indicating that Orai1 can be targeted by miRNAs during in VSMCs. Conclusions In conclusion, our data confirms that Orai1 is upregulated during neointima formation associated with miRNAs dysregulation. Moreover, we found that Orai1-dependent SOCE can be finely regulated by miRNAs during restenosis.

Application of Next-Generation Sequencing (NGS) Techniques for Selected Companion Animals.

Next-Generation Sequencing (NGS) techniques have revolutionized veterinary medicine for cats and dogs, offering insights across various domains. In veterinary parasitology, NGS enables comprehensive profiling of parasite populations, aiding in understanding transmission dynamics and drug resistance mechanisms. In infectious diseases, NGS facilitates rapid pathogen identification, characterization of virulence factors, and tracking of outbreaks. Moreover, NGS sheds light on metabolic processes by elucidating gene expression patterns and metabolic pathways, essential for diagnosing metabolic disorders and designing tailored treatments. In autoimmune diseases, NGS helps identify genetic predispositions and molecular mechanisms underlying immune dysregulation. Veterinary oncology benefits from NGS through personalized tumor profiling, mutation analysis, and identification of therapeutic targets, fostering precision medicine approaches. Additionally, NGS plays a pivotal role in veterinary genetics, unraveling the genetic basis of inherited diseases and facilitating breeding programs for healthier animals. Physiological investigations leverage NGS to explore complex biological systems, unraveling gene-environment interactions and molecular pathways governing health and disease. Application of NGS in treatment planning enhances precision and efficacy by enabling personalized therapeutic strategies tailored to individual animals and their diseases, ultimately advancing veterinary care for companion animals.

Ethical considerations in companion animal care: Examining the consequences of rabies in an unvaccinated Boerboel dog and implications for animal welfare policies

AbstractThis case investigates and documents the occurrence of rabies in an unvaccinated 4‐month‐old Boerboel dog in Ebonyi State, Nigeria, emphasising the ethical considerations and implications for existing animal welfare policies. Despite Nigeria enacting the Animal Diseases (Control) Act, 2022, cases of rabies persist, contributing to thousands of human rabies cases annually. The legal framework highlights the ethical responsibilities of pet owners, mandating annual rabies vaccinations and holding owners accountable for their pets' actions. This case report details the dog's behavioural changes, subsequent euthanasia and laboratory confirmation of rabies. Investigations reveal gaps in vaccination compliance with challenges in community cooperation for free vaccination initiatives. The case highlights the global significance of rabies control, highlighting the ethical responsibilities of pet owners, emphasises the consequences of rabies, and advocates for strengthened policies and improved compliance to effectively combat rabies and protect both animal and human welfare in Nigeria.

EVALUACIÓN Y RECONOCIMIENTO DEL DOLOR EN REPTILES: UNA REVISIÓN SISTEMÁTICA

Reptiles show morpho-physiological differences compared with other taxa (e.g., mammals), such as their pain manifestation that are not obvious to people. Presently, a great part of animal care practitioners lack enough knowledge to evaluate pain behaviors in reptiles, partially because there is not enough research on the subject. The aim of this review is to perform a systematic research about pain identification and assessment through postural and behavioral changes in reptiles. A bibliographic search was made using commands constituted by words related to pain and reptile species connected by boolean operators. The search resulted in 751 articles, although only 43 of them were used based on the eligibility criteria. Information obtained was grouped into three categories. The first were articles on specific nociceptive response trials, in this group two different pain methodologies were observed in all the reptiles groups: Withdrawal time to irritable stimulus (thermal or mechanic) and response to parenteral irritating chemical. The second category included tudies in which postural or behavioral changes associated with pain were mentioned. The third category were review articles. Considering the information published nowadays, we consider that it would be insufficient to evaluate pain in reptiles using one single method. Since most sources mention comparison with normal behaviors, elaborate ethograms of individuals or species (in captivity) during a pain-free period could be useful to identify periods of discomfort. However, more studies are needed to ensure correlation between pain and behaviors.

'Down pythons' throats we thrust live goats': snakes, zoos and animal welfare in nineteenth-century Britain.

In nineteenth-century Britain, captive snakes in menageries and zoological gardens were routinely fed with live prey - primarily rabbits, pigeons and guinea pigs. From the late 1860s, this practice began to generate opposition on animal welfare grounds, leading to a protracted debate over its necessity, visibility and morality. Focusing on the c.1870-1914 period, when the snake-feeding controversy reached its zenith, this article charts changing attitudes towards the treatment of reptiles in captivity and asks why an apparently niche practice generated so much interest. By looking at the biological arguments put forward for and against live feeding, the article traces the changing nature of humanitarian activism in the late nineteenth century and shows how the shifting character of the live-feeding debate paralleled wider trends in the animal welfare movement. It also highlights the different types of knowledge and expertise involved in the debate, as naturalists, veterinary surgeons, legal professionals, zookeepers and humanitarians offered conflicting perspectives on questions of reptilian dietary requirements and animal sentience.

The evolution of the FARM Animal Care program: Trends, priority issues and opportunities for veterinarians

The FARM Program’s goal is to assist U.S. dairy farmers, par­ticipating cooperatives and processors in providing assurance to dairy buyers that U.S. dairy farmers care for their animals, workforce and land in a humane and ethical manner. Over 17,000 second-party evaluations and 480 third-party verifica­tions have been conducted on U.S. dairy farms under Version 4 of the animal care program. Though the majority of farms meet FARM standards, lack of a VCPR and herd health plan signed by the veterinarian in the past 12 months, missing/incomplete continuing education records for employees, not meeting the benchmark for broken tails, lack of pain control for disbud­ding, and incomplete drug treatment records are the most com­mon corrective actions. Overall, a high percentage of herds have met animal observation benchmarks (99% knee lesions, 98% body condition, 97% locomotion, 95% hock lesions, 91% hygiene, and 85% broken tails). Veterinarians are positioned as a critical resource in this program; they are not only needed to comply with program standards and when out of compliance, have a specific opportunity to consult, advise, guide and sup­port clients regarding the health and welfare of their herd.

Smart Cattle Care: An IOT Based Monitoring and Management System

The "Smart Cattle Care" system, which utilizes Internet of Things (IoT) technology to alter the way cattle are monitored and cared for in agricultural settings, marks a ground-breaking innovation in livestock management. This ground-breaking system combines a network of specialized sensors, wearables, and communication modules to gather and transmit real-time data on important aspects like location, environmental conditions, and health measurements. After that, using cloud-based platforms and cutting-edge analytics and artificial intelligence algorithms, the data is processed and examined. This all-encompassing strategy equips farmers with timely knowledge about the health and behavior of their cattle, allowing for proactive disease detection, improved breeding management, and increased overall productivity. The technology also allows for automatic regulation of feeding and climate, ensuring the provision of ideal circumstances for living. Smart Cattle Care greatly improves operational efficiency, lowers costs, and ultimately promotes enhanced animal care and agricultural sustainability by providing a user-friendly dashboard interface and rapid notifications. This study provides a thorough description of the Smart Cattle Care system, emphasizing its essential features, advantages, and prospective effects on contemporary livestock management techniques.

204 Detecting subclinical mastitis in meat-breed ewes using infrared thermography

Abstract Mastitis, the inflammation of the mammary gland most commonly due to bacterial infection, is an important welfare concern in meat-breed sheep. The objective of our study was to evaluate udder surface temperature obtained from infrared thermography as a diagnostic tool for subclinical mastitis. We predicted that udder halves with subclinical mastitis would have greater surface temperatures than healthy udder halves. We enrolled 39 meat-breed ewes (10 Hampshire, 24 Polypay, 5 Targhee; 2 to 9 yr of age) at the University of Wisconsin-Madison sheep unit. All procedures were approved by the UW-Madison Institutional Animal Care and Use Committee. Milk samples from each udder half were collected in duplicate weekly beginning 2 to 4 d postpartum until 8 wk postpartum. Immediately before milk sampling, the udder was photographed from the rear using a thermal camera. A sample was considered a true infection if at least 100 CFU/mL of a bacterial species were isolated. From each photo, we obtained values for minimum, maximum, and mean skin surface temperature for the right and left udders. Three linear mixed models were fit using minimum, maximum, and mean temperatures as the response variables. Fixed effects were infection status (infected or not), weeks postpartum (wk 1-8), and ambient temperature, with a random effect of udder half nested within animal ID. Contrary to our predictions, infection status did not predict udder skin surface temperature (P > 0.12). Healthy udder halves had a mean temperature of 35.5 ± 0.1°C (mean ± SE), minimum temperature of 29.9 ± 0.3°C, and maximum temperature of 37.8 ± 0.1°C. Infected udder halves had a mean temperature of 35.4 ± 0.1°C, minimum temperature of 30.5 ± 0.3°C, and maximum temperature of 37.7 ± 0.1°C. Our results contradict findings in dairy cows, and suggest more research is needed to evaluate the relationship between udder surface temperature and subclinical mastitis in sheep.

304 What does Prop 12 mean for the swine industry

Abstract California’s Proposition 12, also known as the Farm Animal Confinement Initiative, has been fully implemented as of January 1st, 2024. This measure regulates the minimum space requirements for egg-laying hens, dairy calves raised for veal, and breeding pigs in order for the associated products to be sold within the state of California. Suppliers of these covered products need to be accredited by specific, third-party certifying agents to be certified as ‘Prop 12 compliant’. For the swine industry, the spotlight is on the housing of any female breeding pig over the age of 6 mo. These animals must be in an enclosure that allows them to lie down, stand up, turn around, and fully extend their limbs without touching the sides of their stalls or another animal (24 square feet of floor space per animal). These regulations also limit the duration of time producers can house animals in closed crates before farrowing to 5 d. While these housing regulations do not apply during the nursing phase, research contexts, during veterinary treatment or immediately before slaughter, they do apply in the post-weaning phase. This means that the animals cannot be confined for heat-checking or breeding to be considered ‘Prop 12 compliant’. These housing standards have no minimum herd size and apply to those in commercial or private farms if there will be products produced and sold. With any change to the standard operating procedures of animal husbandry, there will be some growing pains. These issues can be addressed when considerations are given to the group composition (age and size of sows), pen mixing practices (pre or post breeding), feeding schedule [collective (trough, floor fed) or individual (electronic sow feeding, free access stalls)], and, pen structural quality (flooring, enrichment). This measure will have considerable economic and ethical implications related to barn renovations, animal care staff training, and husbandry practices for the swine industry.

Nursing Behavior of Bottlenose Dolphin (Tursiops truncatus) Calves from 1990-2014 at Brookfield Zoo Chicago, USA

While the common bottlenose dolphin (Tursiops truncatus) population under managed care in North American zoos and aquariums is self-sustaining, understanding normal nursing behavior can help management make informed care decisions for neonates and future births. This study examined behavioral data from the first 30 days of life collected from 14 dolphin calves born between 1990-2014 at Brookfield Zoo Chicago in Brookfield, IL. We hypothesized that surviving calves showed significantly different patterns of nursing than those that did not survive. There were no significant differences in average nursing rates or average nursing frequency between calves that did and did not survive up to 17 days old. Surviving calves up to eight days old had significantly longer average nursing performance (s/hr), and significantly longer average nursing durations (s/bout) than non-surviving calves. Shorter nursing duration early in the life of the calf may be indicative of developmental problems and may be a useful metric to inform staff when supplemental care may be needed. Calf survival improved from the first half to the second half of the study period by 150%, most likely due to improvements in animal care, medical intervention, and experience of the dams. Understanding normal nursing behavior is essential to learning when human intervention is necessary to help survival and can help guide future care and management of dolphin births under professional care.

Treatment of Hypotension with Phenylephrine Increases Cerebral Microvascular Perfusion in a Rat Model of Acute Hemodilution

Intraoperative blood loss is associated with reduced mean arterial blood pressure (MAP), which may endanger vital organ perfusion, including the brain. Phenylephrine (PE), an α1-receptor agonist, is clinically utilized to treat intraoperative hypotension through vasoconstriction of resistance arterioles. Clinical studies suggest that raising MAP with PE may decrease perfusion to vital organs such as the brain. Experimental studies suggest that lower α-receptor density in the cerebral resistance arteries may lead to preserved brain perfusion after PE administration. We hypothesize that treatment of hypotension with PE will result in preserved brain perfusion due to different microvascular blood flow and tissue oxygen tension (pO2) responses in the brain and skeletal muscle in an experimental rat model. With Animal Care and Use Committee approval in accordance with ARRIVE-2 guidelines, spontaneously breathing anesthetized rats (1.5% isoflurane) underwent hemodilution by exchanging 40-50% estimated blood volume 1:1 with saline over 10 minutes to achieve a 10-20 mmHg drop in MAP. MAP (tail artery) was measured continuously. Hypotension was treated with PE (10-20 μg/kg/min iv) to increase MAP to a target above baseline MAP. Shed blood was re-infused after stopping the PE infusion. Microvascular blood flow (Oxyflo; Oxford Optronix, Oxford, UK, n=7) or microvascular pO2 (OxyLED, Oxyphor G4, Oxygen Enterprises Ltd., Philadelphia, PA, n=6) were measured continuously in the cerebral cortex (burr hole) and biceps femoris muscle simultaneously in each rat. Results were analyzed via one or two-way ANOVA, with significance achieved at p<0.05. Baseline and post-hemodilution MAP values were comparable in both groups. PE infusion increased MAP to a mean level near 100 mmHg in both groups (p<0.05). Microvascular blood flow and tissue pO2 were greater in the brain as compared to the muscle at all time points (p<0.01 for both). PE infusion resulted in an increase in cerebral microvascular blood flow from baseline (1465±689 vs. 687±453 blood perfusion units (BPU); p<0.001) that was sustained after discontinuing PE and during blood reinfusion. No changes in muscle microvascular flow were observed after PE infusion (294±129 vs. 168±113 BPU). A sustained increase in cerebral microvascular pO2 was measured following PE infusion (50.2±8.6 vs. 40.6±4.6 mmHg; p=0.02), whereas muscle tissue pO2 did not change (22.2±5.6 vs. 25.0±2.5 mmHg). A differential blood flow and microvascular pO2 response was observed following PE infusion in brain and skeletal muscle. Both cerebral microvascular blood flow and tissue pO2 demonstrated sustained increases after PE infusion. By contrast, no changes were observed in muscle microvascular blood flow and pO2. These results suggest that treatment of hypotension with PE administration preferentially increased cerebral vs. muscle perfusion in an experimental model of acute blood loss and fluid resuscitation. Canadian Anesthesiologists’ Society and University of Toronto Merit Award Support. 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.

Settler Colonial Classifications of Edibility

The pastoral economies introduced during the colonial invasion have radically transformed Australian diets, cultures, and ecosystems. Stolen land was tenured to settlers and emancipated convicts to develop profitable and productive enterprises for the British Empire. Land rights and animal care are intrinsically linked to modern food systems, yet there is a gap in Australian literature regarding the legacy of colonial pastoralism and its connection to current food systems. This essay questions how introduced species evolved to command the Australian diet. Wallabies and kangaroos were legally relegated to national emblems, and thus inedible. Their conditions of being, whether edible, iconic, or wild, were dictated by the Commonwealth Government. The taboo nature of these native marsupials leaves them largely unconsumed, and therefore, unprotected. Modern conditions of edibility are less concerned with physical metabolic matters, instead driven by historic cultural attitudes and political and economic motives. Nourishment was commodified. My research uses Tasmanian legal archives in conjunction with cookbooks and popular iconography to trace the historical legacies of foodways since the invasion. Scholarship around waste, sociology, ecology, and food justice and sovereignty are incorporated to consider how modern agricultural practices perpetuate violence against Aboriginal and Torres Strait Islander peoples and ecosystems. Modern agriculture affects every being on the planet, both human and more-than-human. My research goal is to encourage people to question their metabolic practices to ascertain how everyday acts of consumption implicate them within unjust systems. Though consumptive wallaby culling is legal, the industry remains privatized, and Indigenous Australians have little agency to influence how their native species are used, and who profits from their utility. By sharing these concerns with researchers from a broad range of disciplines, I hope to connect with individuals who can help to make future metabolic matters more inclusive, more ethical, and more sustainable.

A possible physiological role of sclerostin in aging-associated skeletal muscle atrophy

Sarcopenia has a significant impact on quality of life by inhibiting the ability of daily living. Further, sarcopenia is a well-known risk factor for fall-associated fracture and frailty. Therefore, prevention of sarcopenia is an important issue for healthy life. Recently, it has been revealed that sclerostin (Sost) is a novel target for the treatment of aging-associated bone weakness, so-called osteoporosis, However, the physiological role of Sost in skeletal muscle is unknown. The purpose of this study was to investigate the effect of Sost for skeletal muscle mass. In order to investigate the effect of Sost on myogenic differentiation, we carried out cell culture experiment using mouse myoblast-derived cell line C2C12 cells. During differentiation, Sost (0, 10, 100, 1000 ng/ml) was administrated to the cell culture medium. Effects of anti-sclerostin antibody romosozumab (0, 2, 20, 200 μg/ml) on myotube formation of C2C12 was also investigated. Myotube diameter and the fusion index (FI) and evaluated. Furthermore, we also investigated the expression level of Sost in skeletal muscles of young (10-week old) and aged (100-week old) male mice (C57BL/6J). The effects of hindlimb unloading on the expression level of Sost in skeletal muscle was also investigated. All animal experimental procedures were carried out in accordance with the Guiding Principles for the Care and Use of Animals in the Field of Physiological Sciences by Japan Physiological Society, and approved by the Animal Use Committee of Toyohashi SOZO University. Soleus muscle (SOL) and plantaris muscle (PLA) were dissected before and after 2 weeks of hindlimb suspension. Expression level of Sost was evaluated by Western blotting. The relationship between Sost expression level in each muscle and muscle wet weight was analyzed using Pearson correlation coeffcient. The differences between groups were considered statistically significant at p < 0.05. Sost suppressed myogenic differentiation of C2C12 cells in a dose-dependent manner. On the other hand, romosozumab stimulated C2C12 differentiation in a dose-dependent manner. Expression level of Sost in SOL and PLA of aged mice was significantly higher than that in young animals. In SOL and PLA, a negative correlation was observed between the expression level of Sost and muscle weight was observed. Unloading-associated up-regulation of Sost was observed in PLA of aged mice. We demonstrated aging-associated up-regulation of Sost in mouse slow and fast skeletal muscles. Further, skeletal muscle weight was negatively correlated with the expression level of Sost in skeletal muscle. Therefore, it is suggested that skeletal muscle-derived Sost may play a role in aging-associated skeletal muscle atrophy. Sost may be a novel therapeutic target for sarcopenia. This work was supported by KAKENHI (18H03160, K.G.; 19K22825, K.G.; 19KK0254, K.G.;22H03474, K.G.; 22K19722, K.G.; 22H03319, K.G.; 22K18413, K.G.; 20K11221, T.K) from the Japan Society for the Promotion of Science, and a grant from DAIKO FOUNDATION (K.G.), Graduate School of Health Science, Toyohashi SOZO University (K.G.), and a research grant from Toyohashi SOZO university (K.G.). 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.

Effect of Maternal High Fat Diet on the Hypothalamus-Pituitary-Adrenal Gland (HPA) Axis of the Offspring in Sheep

Maternal consumption of a high fat diet (HFD) during pregnancy is associated with metabolic dysfunction and altered HPA axis function in the offspring. These effects are well established in species with short gestation length (e.g., rodents), but less established in species with longer gestation periods more comparable with humans. The objective of the study was to determine the effect of maternal HFD on basal and stimulated cortisol secretion in the offspring at 16 weeks of age in sheep. All experiments were approved by the Institutional Animal Care and Use Committee at Cal Poly Pomona. Pregnant ewes were assigned to control (n=3) and HFD (n=3) groups. The control group was fed farmers best complete ewe and ram pellets. The HFD group was fed the same diet with an additional 30% rumen protected fat (Megalac, Volac Wilmar Feed Ingredients Ltd). After birth lambs were weaned at 12 weeks of age and given free access to control pellet diet with grains. To assess adrenal cortisol secretion at 16 weeks, lambs were infused intravenously with adrenocorticotropic hormone (ACTH; 2 ug/kg cortrosyn in 1 mL saline). Blood samples (1 mL) were taken through the jugular catheter at −30, −15, and 0 min (immediately before) and 5, 15, 30, 60, 90, and 120 min after ACTH administration for measurement of plasma cortisol by ELISA. Data were analyzed by two-way repeated measures ANOVA with a Tukey posthoc test. Basal plasma cortisol tended to be higher in HFD (32±8 ng/mL) than control (13±3 ng/mL) lambs, but this did not reach statistical significance. Plasma cortisol was higher than baseline from 15 to 90 minutes after ACTH administration in all lambs (p<0.05). The increment in plasma cortisol was higher in HFD than control lambs from 15-90 minutes (p<0.05). Accordingly, the maximum increase in plasma cortisol at 60 minutes and was higher in HFD (245±8 ng/mL) than control lambs (121±50 ng/mL p<0.05). These preliminary data suggest that maternal consumption of a high fat diet during pregnancy may increase basal and stimulated activity of the HPA axis in sheep. The study was funded by a Strategic Interdisciplinary Research Grant (SIRG) at California State Polytechnic University, Pomona. 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.

Shenqi Pill Mitigates Renal Interstitial Fibrosis ThroughWeakening Notch1/Jag1 Pathway.

Shenqi pill (SQP) can be used to treat various kidney related diseases, but its exact mechanism of action remains unclear. We intended to analyze the role and mechanism of SQP on renal interstitial fibrosis (RIF). After performing unilateral ureteral obstruction (UUO) surgery following the Institutional Animal Care and Use Committee guidelines, all rats were assigned into the sham group, UUO group, UUO + SQP 1.5 g/kg, UUO + SQP 3 g/kg, and UUO + SQP 6 g/kg groups. After treatment with SQP for 4 weeks, the appearance of kidney, serum creatinine (SCr), and blood urea nitrogen (BUN) levels were monitored in each group. The pathological injury, extracellular matrix (ECM), and Notch1 pathway-related protein levels were measured using H&E staining, Masson staining, immunohistochemistry, and Western blot, respectively. SQP could obviously ameliorate the appearance of the kidney as well as the levels of SCr and BUN in UUO rats (SCr: 67.6 ± 4.64 μM, 59.66 ± 4.96 μM, 48.76 ± 4.44 μM, 40.43 ± 3.02 μM for UUO, low, medium, and high SQP treatment groups; BUN: 9.09 ± 0.97 mM, 7.72 ± 0.61 mM, 5.42 ± 0.42 mM, 4.24 ± 0.34 mM for UUO, low, medium, and high SQP treatment groups; P < .05). SQP also effectively mitigated renal tissue injury in UUO rats (P < .05). Moreover, we uncovered that SQP significantly inhibited Collagen I, α-SMA, Collagen IV, TGF-B1, Notch1, and Jag1 protein expressions in UUO rats kidney (P < .05). Our data elucidated that SQP can alleviate RIF, and the mechanism may be related to the Notch1/Jag1 pathway. DOI: 10.52547/ijkd.7703.

Exploring a Role for Gut Microbiota to Modulate Aldosterone

Hypertension is associated with an increased risk of mortality for numerous conditions including heart disease, diabetes, and renal disease (D. Aune, Biomed Res Int, 2021). Hypertension is often viewed as idiopathic and treatment is seldom aimed at addressing an underlying mechanism; however, a recent study indicates that primary aldosteronism is an underappreciated cause of idiopathic hypertension (J. Brown, Ann Intern Med, 2020). Here, we investigate for the first time the influence of gut microbiota on aldosterone regulation. To pursue this, we used C57Bl/6 mice (n=20; males) housed in the Johns Hopkins Animal Care Facility and fed a specific pathogen-free diet. Whole blood from submandibular cheek bleeds were collected into K2EDTA-treated tubes at baseline and mice were allowed to recover. Mice were then treated with antibiotics (ABX; 1g/L ampicillin, 1g/L neomycin, and 0.5g/L vancomycin) in their drinking water ad libitum for a total of 7 days to dramatically suppress gut microbes. Whole blood via submandibular cheek bleeds were collected after 24hrs, and at day 7 on ABXs. Mice were sacrificed on day 7 of ABX. Plasma samples from baseline, 24hrs on ABX and 7 days on ABX were used to determine aldosterone concentration and plasma renin activity (PRA) via ELISA. In addition, 24hr urine samples were collected at baseline and at day 7 on ABXs. Statistics were calculated using paired, one-way ANOVA; data below are mean ± SD. Our results demonstrate that plasma aldosterone and PRA, as well as urine aldosterone, were significantly increased from baseline to 7 days on ABX treatment (plasma aldo (pg/mL): 295.1 ± 164.8 vs 634.9 ± 290.4, p= 0.0197; plasma PRA (ng Ang-1/mL/hr): 191.8 ± 137.6 vs 325.9 ± 141.5, p= 0.0108; urine aldo (pg/mL): 2019 ± 322.1 vs 2668 ± 292.0, p = 0.0047). However, there was no significant difference in plasma aldosterone from baseline to 24hrs on ABX treatment (295.1 ± 164.8 vs 434.5 ± 245.3, p= 0.1047). In contrast, we observed a significant increase in angiotensin I from baseline to 24hrs on ABX treatment (191.8 ± 137.6 vs 355.8 ± 139.6, p=0.0041), and this increase was sustained until day 7 (325.9 ± 141.5 vs baseline, p=0.0108). Preliminary data suggest aldosterone is also increased in the plasma of germ-free mice (without gut microbes) compared to conventionalized controls (750.4 ± 265.0, n= 6, vs 314.4 ± 260.3, n=4, p=0.0667), implying that gut microbiota normally act to suppress plasma aldosterone. Taken together, we demonstrate that in the absence of gut microbiota, plasma aldosterone, urine aldosterone, and PRA are significantly increased. Understanding how gut microbes influence aldosterone levels could provide valuable insights into the development and treatment of hypertension. This knowledge may open new avenues for therapeutic interventions, such as probiotics or dietary modifications, to help regulate blood pressure. William Townsend Porter Predoctoral Fellowship from the American Physiological Society (BNM), Johns Hopkins Post-baccalaureate Research Education Program (PREP; R25GM109441 to ADM), the NIDDK Diabetic Complications Consortium (RRID:SCR_001415m www.diacomp.org, grants DK076169 and DK 115255 (subaward to JLP)) and American Heart Association Established Investigator Award (to JLP). 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.

High Fat Feeding Blunts Skeletal Muscle Oxygen Mediated Blood Flow Responses in Healthy and Type 2 Diabetic Rats

Hypothesis: High fat diet feeding impairs microvascular blood flow responses to dynamic changes in local oxygen concentration ([O2]) in Sprague-Dawley (SD) and Zucker Diabetic Sprague-Dawley (ZDSD) rats. Methods: Seven-week-old male SD and ZDSD rats were fed either a standard chow (N = 7 SD, 5 ZDSD) or a high saturated fat diet (N = 8 SD, 6 ZDSD) for 7 weeks. At 14 weeks of age animals were anaesthetized, instrumented for systemic monitoring, and mechanically ventilated. The extensor digitorum longus muscle was blunt dissected and reflected over a gas exchange chamber imbedded in the stage of an inverted microscope. Microvascular blood flow responses to high and low [O2] challenges (7 – 12 %, and 7 – 2 %) and sequential changes in [O2] (7 – 12 – 2 – 7 %) were recorded at baseline and during hyperinsulinemic-euglycemic clamp. Gas conditions within the chamber were set at 7 % for a 1-minute baseline followed by 2 minutes at either 2 or 12 % O2. The 4-minute square wave oscillation consisted of 1 minute at each [O2] (7 – 12 – 2 – 7 %). Hyperinsulinemic-euglycemic clamp was achieved by simultaneous infusion of insulin (2 U/hr/kg) and variable rate of 50 % glucose until euglycemia was reached (5 - 7 mM blood glucose). Analysis of intravital videos was completed using custom MATLAB software. All animal protocols were approved by Memorial University’s Animal Care Committee. Results: Chow fed SD had significantly higher glucose infusion rates compared to high fat fed SD, chow fed ZDSD, and high fat fed ZDSD (28.11 ± 1.807 vs. 25.14 ± 1.18, 24.56 ± 2.78, 24.77 ± 2.43 mg/kg/min, p = 0.0429, 0.0305, 0.0323, respectively). Red blood cell (RBC) saturation significantly increased and decreased in all groups within 4 s following the increase and decrease in [O2], respectively. Chow fed SD had significant decrease in RBC supply rate (SR) in response to 12 % [O2] (10.41 ± 11.31 vs 7.44 ± 8.40 cells/s, p &lt; 0.0001, τ = 15.85 s). In response to low [O2], significant increases in SR were measured in the chow fed SD and ZDSD groups (7.10 ± 8.76 vs 11.65 ± 11.36 cells/s, p &lt; 0.0001, τ = 17.65 s, and 10.86 ± 13.62 vs 13.86 ± 14.69 cells/s, p &lt; 0.0001, τ = 85.74 s, respectively). High fat fed SD and ZDSD had significant increases in RBC SR during 2 % [O2] (8.47 ± 9.75 vs 11.84 ± 12.11 cells/s, p &lt; 0.0001, τ = 68.49 s, and 16.09 ± 18.12 vs 20.73 ± 21.92 cells/s, p &lt; 0.0001, τ = 23.98 s). High fat fed ZDSD had higher, but not significantly different, baseline RBC SR compared to the chow fed ZDSD group. Chow fed SD were the only group to have an increase in RBC SR at low [O2] during hyperinsulinemic-euglycemic clamp (13.80 ± 17.78 vs 18.07 ± 20.25 cells/s, p = 0.0003, τ = 10.88 s). Conclusions: High fat feeding impairs the capillary blood flow response to local increases in [O2] in healthy and high fat fed T2D model rats. Chow fed ZDSD rats had slower capillary blood flow dynamics than the SD control group. Hyperinsulinemic-euglycemic clamp diminishes the O2 mediated blood flow response in 14-week-old SD and ZDSD rats fed a high fat diet. This project was supported by the Canadian Institute of Health Research through a project grant to GMF. Studentships were supported by Memorial University's School of Graduate Studies and the Faculty of Medicine. 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.

Carbon Dioxide Concentration Alters the Dynamics of Oxygen-Mediated Capillary Blood Flow Response s in Skeletal Muscle

Objective: We sought to quantify how different muscle carbon dioxide concentrations ([CO2]) alter the dynamics of oxygen-mediated blood flow responses in skeletal muscle capillaries. Methods: 6 male Sprague Dawley rats (164-215g) were anaesthetized, instrumented for systemic monitoring, and mechanically ventilated. The extensor digitorum longus muscle was isolated via blunt dissection, externalized, and reflected over a microfluidic gas exchange chamber mounted in the stage of an inverted microscope. Intravital video of capillary blood flow was recorded during 4-minute O2 challenges consisting of a 1-minute baseline at 7% oxygen concentration ([O2]), followed by 3 minutes at 2% [O2]. Before recordings, the muscle was equilibrated to constant background [CO2] of either 2%, 5%, or 8% for 5 minutes. Recordings were analyzed offline using custom MATLAB software. The time transients () of capillary hemodynamic responses were determined using a least-squared regression fit (LSRF) to single- and double-exponential models. All animal protocols were approved by Memorial University’s Animal Care Committee. Results: Baseline red blood cell (RBC) velocity was significantly different at 5% [CO2] (213.2±179.4 μm/s) compared to 2% [CO2] (177.7±162.6 μm/s, p=0.0016), and 8% [CO2] (250.3±193.6 μm/s, p&lt;0.0001). RBC oxygen saturations (SO2) were significantly different beyond 3 s post-baseline in all [CO2] conditions ( p&lt;0.02, =3.2-4.3s). Minimum RBC SO2 was 52%, 46%, and 38% below baseline at 12s, 14s, and 12s for 2%, 5%, and 8% [CO2] conditions, respectively. RBC velocity was significantly increased during 2% [CO2] by 3 s post-baseline (177.7±162.6 vs 188.7±168.6 μm/s, p&lt;0.0001), during 5% [CO2] by 6 s post-baseline (213.2±179.4 vs 224.2±189.9 μm/s, p=0.0190), and during 8% [CO2] by 12 s post-baseline (250.3±193.6 vs 267.0±199.9 μm/s, p=0.0062). Time transients of the fast component of the oxygen-mediated velocity response, as determined by LSRF, were 1.9s for 2% [CO2], 4.8s for 5% [CO2], and 9.8s for 8% [CO2]. Velocity was increased at the end of the O2 challenge by 39%, 33%, and 36% during 2%, 5%, and 8% [CO2] conditions, respectively. Baseline RBC supply rate (SR) was significantly different at 5% [CO2] (13.5±18.9 cells/s) compared to 2% [CO2] (9.5±15.3 cells/s, p=0.0090), and 8% [CO2] (19.0±23.6 cells/s, p&lt;0.0001). At 2% [CO2], SR increased significantly by 9 s post-baseline (9.5±15.2 vs 10.9±16.9 cells/s, p=0.0001), by 10 s post-baseline for 5% [CO2] (13.5±18.9 vs 14.9±20.6 cells/s, p=0.0099), and by 13 s post-baseline during 8% [CO2] (19.0±23.6 vs 21.1±25.2 cells/s, p=0.0204). The fast component of the oxygen-mediated SR response had a of 2.7s for 2% [CO2], 4.5s for 5% [CO2], and 6.9s for 8% [CO2] as determined by LSRF. Overall SR was increased by 74%, 51%, and 39% at the end of the O2 challenge during 2%, 5%, and 8% [CO2], respectively. As well, capillary hematocrits were significantly different during baseline at 5% [CO2] (21.4±16.1%) compared to 2% [CO2] (18.2±22.2%, p=0.0113), and 8% [CO2] (27.2±21.4%, p&lt;0.0001). Conclusion: We have quantified the fast component of oxygen-mediated capillary hemodynamic responses to an acute decrease in skeletal muscle [O2]. The time transients of O2-mediated responses vary with tissue [CO2] such that increasing CO2 results in slower response dynamics. As well, increasing background [CO2] provokes higher capillary RBC velocity, SR, and hematocrit both at baseline and during low O2 challenges as expected. This project was supported by a Natural Sciences and Engineering Research Council of Canada Discovery Grant awarded to GMF. Student support was provided by Memorial University's School of Graduate Studies and Faculty of Medicine. 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.

Changes in preBötzinger Complex neuron discharge associated with changes in PCO2 in decerebrate rabbits

Background: Maskrey and Nicol reported a strong increase in minute ventilation with increase in PCO2 (J Physiol 1980, 301: 49-58). We investigated a) whether there was a ceiling to this effect at high CO2 levels and b) whether the change in ventilation was associated with specific changes in respiratory neurons in the preBötzinger complex (preBC). Methods: The study was approved by the local Animal Care Committee and conformed to NIH standards. Adult New Zealand White rabbits (3-4 kg) were anesthetized, tracheotomized, ventilated, decerebrated and vagotomized. Phrenic nerve activity was recorded from the C5 rootlet, time averaged and used to calculate inspiratory (TI) and expiratory durations (TE) and peak phrenic activity (PPA). PPA was normalized to the value at PCO2 50mmHg. Individual neurons were recorded in the functionally identified preBC using multichannel electrodes at increasing CO2 levels. Statistical analysis used the Wilcoxon signed-rank test to determine changes in respiratory parameters between CO2 levels and Friedman RM-ANOVA to determine changes in neuronal discharge frequency (Fn). A generalized linear mixed model was used to determine associations between CO2-dependent changes in TI, TE, PPA, and changes in Fn for different neuron types. p&lt;0.05 indicated a significant difference. Results: In 34 animals, the increase in minute ventilation with increasing PCO2 was due mostly to the change in PPA. The increase in respiratory rate was due mostly to a decrease in TE. There was little increase in respiratory output at PCO2 &gt; 50 mmHg. In 209 neurons, increasing PCO2 increased Fn in inspiratory augmenting (I aug, n= 70, p&lt;0.0001 for CO2 30 vs 40 and 40 vs 50mmHg), I parabolic (I para, n=43, p&lt;0.0001 for CO2 40 vs 50 mmHg), pre-inspiratory (pre-I, n=35, p&lt;0.01 for CO2 30 vs 40 mmHg), and expiratory decrementing (E dec, n=44, p&lt;0.01 for CO2 40 vs 50 mmHg) neurons, but not in I dec (n=8) and non-respiratory modulated (NRM, n=9) neurons. The strongest correlation was found between the changes in phase timing and PPA and Fn in I aug and pre-I neurons. Conclusion: We found a ceiling effect to the increase in respiratory output at PCO2 levels &gt; 50 mmHg. Inspiratory preBC neuron subtypes were more affected by the changes in PCO2. NIH R01HL159546. 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.