Function In Swine Research Articles

Carbon monoxide as a cellular protective agent in a swine model of cardiac arrest protocol.

Out-of-hospital cardiac arrest (OHCA) affects over 360,000 adults in the United States each year with a 50-80% mortality prior to reaching medical care. Despite aggressive supportive care and targeted temperature management (TTM), half of adults do not live to hospital discharge and nearly one-third of survivors have significant neurologic injury. The current treatment approach following cardiac arrest resuscitation consists primarily of supportive care and possible TTM. While these current treatments are commonly used, mortality remains high, and survivors often develop lasting neurologic and cardiac sequela well after resuscitation. Hence, there is a critical need for further therapeutic development of adjunctive therapies. While select therapeutics have been experimentally investigated, one promising agent that has shown benefit is CO. While CO has traditionally been thought of as a cellular poison, there is both experimental and clinical evidence that demonstrate benefit and safety in ischemia with lower doses related to improved cardiac/neurologic outcomes. While CO is well known for its poisonous effects, CO is a generated physiologically in cells through the breakdown of heme oxygenase (HO) enzymes and has potent antioxidant and anti-inflammatory activities. While CO has been studied in myocardial infarction itself, the role of CO in cardiac arrest and post-arrest care as a therapeutic is less defined. Currently, the standard of care for post-arrest patients consists primarily of supportive care and TTM. Despite current standard of care, the neurological prognosis following cardiac arrest and return of spontaneous circulation (ROSC) remains poor with patients often left with severe disability due to brain injury primarily affecting the cortex and hippocampus. Thus, investigations of novel therapies to mitigate post-arrest injury are clearly warranted. The primary objective of this proposed study is to combine our expertise in swine models of CO and cardiac arrest for future investigations on the cellular protective effects of low dose CO. We will combine our innovative multi-modal diagnostic platform to assess cerebral metabolism and changes in mitochondrial function in swine that undergo cardiac arrest with therapeutic application of CO.

Overexpression of CuZn superoxide dismutase improves high-density lipoprotein function in swine

Cardiovascular disease (CVD) has been the leading cause of death worldwide. As a chronic inflammatory disease, atherosclerosis (AS) acts as the initiating factor for CVD and reactive oxygen species (ROS) play a vital role in its development. Superoxide dismutases (SOD) can alleviate the detrimental effects of ROS and serve as the first line of defense through detoxifying the products derived from oxidative stress in vivo. Considering the potential preventive effects of high-density lipoprotein (HDL) on AS and the close relationship between CuZn superoxide dismutase (CuZnSOD) and HDL, the present work investigated whether CuZnSOD overexpression in swine could improve the function of HDL. Seven CuZnSOD transgenic swine, constructed by sperm and magnetic nanoparticles, demonstrated overexpressed CuZnSOD in the liver (P < 0.01) but comparable level to control in plasma (P > 0.05). CuZnSOD overexpression significantly down-regulated the levels of triglyceride (TG), apolipoprotein A-I (apoA-I) (P < 0.05), and high-density lipoprotein cholesterol (HDL-C) (P < 0.01) in plasma. In the presence of CuZnSOD overexpression, HDL3 significantly inhibited levels of IL-6 and TNF-α induced by oxidized low-density lipoprotein (oxLDL) (P < 0.05), indicating enhanced anti-inflammatory activity of HDL. At the same time, HDL-mediated cholesterol efflux did not decrease (P > 0.05). CuZnSOD overexpression improves the anti-inflammatory function of HDL despite decreased levels of HDL-C. In Conclusion, CuZnSOD overexpression improves HDL function in swine.

Intramyocardial injection of hypoxia-conditioned extracellular vesicles modulates apoptotic signaling in chronically ischemic myocardium

ObjectiveLimited treatments exist for nonoperative chronic coronary artery disease. Previously, our laboratory has investigated extracellular vesicle (EV) therapy as a potential treatment for chronic coronary artery disease using a swine model and demonstrated improved cardiac function in swine treated with intramyocardial EV injection. Here, we seek to investigate the potential cardiac benefits of EVs by using hypoxia-conditioned EVs (HEV). Specifically, this study aims to investigate the effect of HEV on apoptosis in chronically ischemic myocardium in swine. MethodsFourteen Yorkshire swine underwent placement of an ameroid constrictor on the left circumflex artery. Two weeks later, swine underwent redo left thoracotomy with injection of either saline (control, n = 7) or HEVs (n = 7). After 5 weeks, swine were euthanized for tissue collection. Terminal deoxynucleotidyl transferase dUTP nick end labeling was used to quantify apoptosis. Immunoblotting was used for protein quantification. ResultsTerminal deoxynucleotidyl transferase dUTP nick end labeling staining showed a decrease in apoptosis in the HEV group compared with the control (P = .049). The HEV group exhibited a significant increase in the anti-apoptotic signaling molecule phospho-BAD (P = .005), a significant decrease in B-cell lymphoma 2 (P = .006) and an increase in the phospho-B-cell lymphoma to B-cell lymphoma 2 ratio (P < .001). Furthermore, the HEV group exhibited increased levels of prosurvival signaling markers including phosphoinositide 3-kinase, phosphor-extracellular signal-regulated kinase 1/2, phospho-forkhead box protein O1, and phospho-protein kinase B to protein kinase B ratio (all P < .05). ConclusionsIn chronic myocardial ischemia, treatment with HEV results in a decrease in overall apoptosis, possibly through the activation of both pro-survival and anti-apoptotic signaling pathways.

Splenic Modulation of Early Post-Infarction Inflammation and Left Ventricular Function in Swine

Objective: Despite a growing body of evidence that the spleen contains a reservoir of leukocytes that can be rapidly mobilized following ischemic injury, the extent to which splenic leukocytes contribute to the early inflammatory response to myocardial infarction (MI) is unclear. Accordingly, we employed a surgical approach to assess the role of the spleen in modulating early post-MI inflammation in swine. Methods: Swine (n=12) were randomized to splenectomy (SPLX; n=6) or sham surgery (SHAM; n=6) 1-week prior to undergoing a 75-minute balloon occlusion of the left anterior descending coronary artery (LAD) to produce MI. Hemodynamic assessment, echocardiography, and venous blood sampling were performed before and up to 3 hours after MI, at which time the heart was collected for post-mortem analysis of infarct size via TTC staining. Flow cytometry was utilized to quantify leukocyte sub-populations in blood and myocardial tissue, while plasma concentrations of cardiac troponin I (cTnI), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were measured via porcine-specific ELISA. Results: The severity of myocardial injury was comparable in both groups, as evidenced by measurement of infarct size (SPLX vs. SHAM: 18±2 vs. 17±3 % of LV mass; p=0.84) and peak post-MI cTnI levels (101±20 vs. 72±9 ng/mL; p=0.21). Early post-MI leukocyte mobilization was also similar between groups (20±6 vs. 20±13 % change from baseline; p=0.97), with no significant between-group differences in circulating neutrophils nor monocytes within the first 3-hours after reperfusion. Quantification of blood and myocardial leukocyte subpopulations based on expression of CD14, CD16, CD163, and CD172 failed to reveal any differences between groups, while each group exhibited a similar rise in circulating levels of IL-6 (p=0.35) and TNF-α (p=0.54). Despite the absence of evidence that splenectomy influenced early post-MI inflammation, LV function was significantly better in SPLX vs. SHAM animals throughout the post-reperfusion period, as indicated by significant elevations in peak LV pressure (104±5 vs. 90±5 mmHg) and LV dP/dtmax (1816±108 vs. 1367±107 mmHg/s; both p&lt;0.05) at the 3-hour timepoint. Conclusion: In contrast to prior studies in rodents demonstrating a contribution of splenic leukocytes to post-MI inflammation at later timepoints, our results indicate that the spleen is not a primary source of circulating or infiltrating leukocytes within the first few hours after reperfusion in swine. Nevertheless, splenectomized animals exhibited improved LV function early after MI despite a comparable infarct size, suggesting that the spleen may modulate post-ischemic cardiac function through leukocyte-independent mechanisms. Supported by funding from the National Institutes of Health (1R01HL160538) and the US Dept. of Veteran's Affairs (1I0BX002659) This is the full abstract presented at the American Physiology Summit 2023 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.

Scrambled eggs-Negative impacts of heat stress and chemical exposures on ovarian function in swine.

Exposure to environmental toxicants and hyperthermia can hamper reproduction in female mammals including swine. Phenotypic manifestations include poor quality oocytes, endocrine disruption, infertility, lengthened time to conceive, pregnancy loss, and embryonic defects. The ovary has the capacity for toxicant biotransformation, regulated in part by the phosphatidylinositol-3 kinase signaling pathway. The impacts of exposure to mycotoxins and pesticides on swine reproduction and the potential for an emerging chemical class of concern, the per- and polyfluoroalkylated substances, to hamper porcine reproduction are reviewed. The negative impairments of heat stress (HS) on swine reproductive outcomes are also described and the cumulative effect of environmental exposures, such as HS, when present in conjunction with a toxicant is considered.

Metagenomic Analysis of the Fecal Archaeome in Suckling Piglets Following Perinatal Tulathromycin Metaphylaxis.

Simple SummaryThe archaeal population, or ‘archaeome’, is comprised of unicellular microorganisms with a distinct biology compared with bacteria and has been shown to be an important component of host-associated microbes. While the impact of antimicrobial administration on gastrointestinal microbiota has been widely evaluated, no metagenomics-based analysis has been performed to assess the impact of an early life antimicrobials intervention on the fecal archaeome in swine. The aim of this study was therefore to investigate the impact of perinatal tulathromycin (TUL) administration on the fecal archaeome composition and diversity in suckling piglets using metagenomic sequencing analysis. Our results suggest that perinatal TUL metaphylaxis seems to have a minimal effect on the gut archaeome composition and diversity in sucking piglets.The gastrointestinal microbiome plays an important role in swine health and wellbeing, but the gut archaeome structure and function in swine remain largely unexplored. To date, no metagenomics-based analysis has been done to assess the impact of an early life antimicrobials intervention on the gut archaeome. The aim of this study was to investigate the effects of perinatal tulathromycin (TUL) administration on the fecal archaeome composition and diversity in suckling piglets using metagenomic sequencing analysis. Sixteen litters were administered one of two treatments (TUL; 2.5 mg/kg IM and control (CONT); saline 1cc IM) soon after birth. Deep fecal swabs were collected from all piglets on days 0 (prior to treatment), 5, and 20 post intervention. Each piglet’s fecal archaeome was composed of rich and diverse communities that showed significant changes over time during the suckling period. At the phylum level, 98.24% of the fecal archaeome across all samples belonged to Euryarchaeota. At the genus level, the predominant archaeal genera across all samples were Methanobrevibacter (43.31%), Methanosarcina (10.84%), Methanococcus (6.51%), and Methanocorpusculum (6.01%). The composition and diversity of the fecal archaeome between the TUL and CONT groups at the same time points were statistically insignificant. Our findings indicate that perinatal TUL metaphylaxis seems to have a minimal effect on the gut archaeome composition and diversity in sucking piglets. This study improves our current understanding of the fecal archaeome structure in sucking piglets and provides a rationale for future studies to decipher its role in and impact on host robustness during this critical phase of production.

A 30% incidence of renal cysts with varying sizes and densities in biomedical research swine is not associated with renal dysfunction.

BackgroundRenal cystic disease arising from various etiologies results in fluid‐filled cavities within the kidneys. Moreover, preexisting renal dysfunction has been shown to exacerbate multiple pathologies. While swine bred for biomedical research are often clinically inspected for illness/parasites, more advanced diagnostics may aid in uncovering underlying renal abnormalities.MethodsComputed tomography was performed in 54 female prepubertal Yorkshire swine to characterize renal cysts; urine and blood chemistry, and histology of cysts were also performed.ResultsDigital reconstruction of right and left kidneys demonstrated that roughly one‐third of the animals (17/54; 31%) had one or more renal cyst. Circulating biomarkers of renal function were not different between animals that had cysts and those that did not. Alternatively, urinary glucose (P = .03) was higher and sodium (P = .07) tended to be lower in animals with cysts compared to animals without, with no differences in protein (P = .14) or potassium (P = .20). Aspiration of cystic fluid was feasible in two animals, which revealed that the cystic fluid urea nitrogen (97.6 ± 28.7 vs 911.3 ± 468.2 mg/dL), potassium (29.8 ± 14.4 vs 148.2 ± 24.85 mmol/L), uric acid (2.55 ± 1.35 vs 11.4 ± 5.65 mg/dL), and creatinine (60.34 ± 17.26 vs 268.99 ± 95.79 mg/dL) were much lower than in the urine. Histology demonstrated a cyst that markedly compresses the adjacent cortex and is lined by a single layer of flattened epithelium, bounded by fibrous connective tissue which extends into the parenchyma. There is tubular atrophy and loss in these areas.ConclusionThis study provides valuable insight for future studies focusing on kidney function in swine bred for biomedical research.

Antimicrobial peptides as novel alternatives to antibiotics

In recent years, due to the unreasonable use of antibiotics, bacterial resistance has increased, posing a huge threat to human health and the healthy development of the swine industry. Therefore, it is an urgent to look for antibiotic alternatives. Antimicrobial peptides are a class of small molecule peptides, which are the body's first line of defense against the invasion of pathogenic microorganisms. They have small molecular weight, good water solubility, and not easy to produce drug resistance. Therefore, antimicrobial peptides are considered as one of the best alternatives to antibiotics. This review focuses on the mechanism of action of antimicrobial peptides, especially improve performance, improve intestinal inflammation and nutrient digestibility, regulate the intestinal microbiota and enhance the immune function of swine. Overall, AMPs have great potential for application as an alternative to antibiotics in swine industry.

Diabetic metabolic dysregulation and chronic kidney disease induce specific perturbations in coronary microvascular function in swine

IntroductionComorbidities such as diabetes mellitus (DM), hypercholesterolemia (HC) and chronic kidney disease (CKD), are often associated with altered coronary microvascular function. However, the specific mechanisms affected by the various comorbidities have not been investigated in detail. Here we studied endothelium‐dependent and ‐independent vasodilation of isolated small coronary arteries, as well as vasoconstrictor responses to endothelin‐1 and their specific mechanisms of action in swine with multiple comorbidities.Methods and ResultsDM (streptozotocin, 150mg/kg i.v.) and hypercholesterolemia (high fat diet) were induced in 10 female swine, which were followed for 6 months (DM+HC). In a separate group of 9 female swine, CKD (by renal artery embolization) was added on top of the two risk factors and animals were followed for 6 months (DM+HC+CKD). 12 female healthy swine on normal pig‐chow served as controls. At sacrifice, coronary small arteries were isolated and vasomotor control was studied in vitro. Both DM+HC and DM+HC+CKD groups showed impaired endothelium‐dependent vasodilation to bradykinin, mainly via loss of EDHF‐dependent mechanism. No changes were seen in the response to the exogenous NO‐donor, SNAP, indicating preserved smooth muscle cell function. Coronary arteries from swine with DM+HC exhibited a blunted vasoconstriction to endothelin‐1, (ET‐1), due to increased ETB‐mediated vasodilation. In contrast, adding CKD to DM+HC resulted in enhanced ET‐1 vasoconstriction.ConclusionDiabetic metabolic dysregulation and chronic kidney disease induce comorbidityspecific perturbations in coronary microvascular function in swine.Support or Funding InformationSupported by grants from the European Commission FP7‐Health‐2010 grant MEDIA‐261409, the Netherlands CardioVascular Research Initiative: an initiative with support of the Dutch Heart Foundation [CVON2014‐11(RECONNECT)] and The Academy of Finland 251272.

Renovascular disease induces mitochondrial damage in swine scattered tubular cells

Scattered tubular-like cells (STCs) contribute to repair neighboring injured renal tubular cells. Mitochondria mediate STC biology and function but might be injured by the ambient milieu. We hypothesized that the microenviroment induced by the ischemic and metabolic components of renovascular disease impairs STC mitochondrial structure and function in swine, which can be attenuated with mitoprotection. CD24+/CD133+ STCs were quantified in pig kidneys after 16 wk of metabolic syndrome (MetS) or lean diet (Lean) with or without concurrent renal artery stenosis (RAS) (n = 6 each). Pig STCs were isolated and characterized, and mitochondrial structure, membrane potential, and oxidative stress were assessed in cells untreated or incubated with the mitoprotective drug elamipretide (1 nM for 6 h). STC-protective effects were assessed in vitro by their capacity to proliferate and improve viability of injured pig tubular epithelial cells. The percentage of STCs was higher in MetS, Lean + RAS, and MetS + RAS kidneys compared with Lean kidneys. STCs isolated from Lean + RAS and MetS + RAS pigs showed mitochondrial swelling and decreased matrix density, which were both restored by mitoprotection. In addition, mitochondrial membrane potential and ATP production were reduced and production of reactive oxygen species elevated in MetS, Lean + RAS, and MetS + RAS STCs. Importantly, mitoprotection improved mitochondrial structure and function as well as the capacity of MetS + RAS STCs to repair injured tubular cells in vitro. Renovascular disease in swine is associated with a higher prevalence of STCs but induces structural and functional alterations in STC mitochondria, which impair their reparative potency. These observations suggest a key role for mitochondria in the renal reparative capacity of STCs.

Dietary Resistant Potato Starch Alters Intestinal Microbial Communities and Their Metabolites, and Markers of Immune Regulation and Barrier Function in Swine.

Interactions between diet, the microbiota, and the host set the ecological conditions in the gut and have broad implications for health. Prebiotics are dietary compounds that may shift conditions toward health by promoting the growth of beneficial microbes that produce metabolites capable of modulating host cells. This study's objective was to assess how a dietary prebiotic could impact host tissues via modulation of the intestinal microbiota. Pigs fed a diet amended with 5% resistant potato starch (RPS) exhibited alterations associated with gut health relative to swine fed an unamended control diet (CON). RPS intake increased abundances of anaerobic Clostridia in feces and several tissues, as well as intestinal concentrations of butyrate. Functional gene amplicons suggested bacteria similar to Anaerostipes hadrus were stimulated by RPS intake. The CON treatment exhibited increased abundances of several genera of Proteobacteria (which utilize respiratory metabolisms) in several intestinal locations. RPS intake increased the abundance of regulatory T cells in the cecum, but not periphery, and cecal immune status alterations were indicative of enhanced mucosal defenses. A network analysis of host and microbial changes in the cecum revealed that regulatory T cells positively correlated with butyrate concentration, luminal IgA concentration, expression of IL-6 and DEF1B, and several mucosa-associated bacterial taxa. Thus, the administration of RPS modulated the microbiota and host immune status, altering markers of cecal barrier function and immunological tolerance, and suggesting a reduced niche for bacterial respiration.

Nonocclusive multivessel intracoronary infusion of allogeneic cardiosphere-derived cells early after reperfusion prevents remote zone myocyte loss and improves global left ventricular function in swine with myocardial infarction.

Intracoronary cardiosphere-derived cells (icCDCs) infused into the infarct-related artery reduce scar volume but do not improve left ventricular (LV) ejection fraction (LVEF). We tested the hypothesis that this reflects the inability of regional delivery to prevent myocyte death or promote myocyte proliferation in viable myocardium remote from the infarct. Swine (n = 23) pretreated with oral cyclosporine (200 mg/day) underwent a 1-h left anterior descending coronary artery (LAD) occlusion, which reduced LVEF from 61.6 ± 1.0 to 45.3 ± 1.5% 30 min after reperfusion. At that time, animals received global infusion of allogeneic icCDCs (n = 8), regional infusion of icCDCs restricted to the LAD using the stop-flow technique (n = 8), or vehicle (n = 7). After 1 mo, global icCDCs increased LVEF from 44.8 ± 1.9 to 60.8 ± 3.8% (P < 0.05) with no significant change after LAD stop-flow icCDCs (44.8 ± 3.6 to 50.9 ± 3.1%) or vehicle (46.5 ± 2.5 to 47.7 ± 2.6%). In contrast, global icCDCs did not alter infarct volume (%LV mass) assessed at 2 days (11.2 ± 2.3 vs. 12.6 ± 2.3%), whereas it was reduced after LAD stop-flow icCDCs (7.1 ± 1.1%, P < 0.05). Histopathological analysis of remote myocardium after global icCDCs demonstrated a significant increase in myocyte proliferation (147 ± 32 vs. 14 ± 10 nuclei/106 myocytes, P < 0.05) and a reduction in myocyte apoptosis (15 ± 9 vs. 46 ± 10 nuclei/106 myocytes, P < 0.05) that increased myocyte nuclear density (1,264 ± 39 vs. 1,157 ± 33 nuclei/mm2, P < 0.05) and decreased myocyte diameter (13.2 ± 0.2 vs. 14.5 ± 0.3 μm, P < 0.05) compared with vehicle-treated controls. In contrast, remote zone changes after regional LAD icCDCs were no different from vehicle. These data indicate that changes in global LVEF after icCDCs are dependent upon preventing myocyte loss and hypertrophy in myocardium remote from the infarct. These arise from stimulating myocyte proliferation and reducing myocyte apoptosis indicating the importance of directing cell therapy to viable remote regions.NEW & NOTEWORTHY Administration of allogeneic cardiosphere-derived cells to the entire heart via global intracoronary infusion shortly after myocardial infarction favorably influenced left ventricular ejection fraction by preventing myocyte death and promoting myocyte proliferation in remote, noninfarcted myocardium in swine. In contrast, regional intracoronary cell infusion did not significantly affect remote zone myocyte remodeling. Global cell administration targeting viable myocardium remote from the infarct may be an effective approach to prevent adverse ventricular remodeling after myocardial infarction.

Abstract 337: Long Term Safety and Efficacy of a Cardiac Graft in a Swine Model of Heart Failure

Introduction: We have shown efficacy with cardiac grafts in the rat coronary ligation model of chronic heart failure (CHF) and feasibility of implantation and assessment in a swine model. Now we propose testing its long term safety and efficacy in a swine model of CHF. Our aims are: 1) Evaluate long term (6 months) left ventricular functional improvements after implantation of the graft in a swine coronary artery occlusion model of CHF, 2) Evaluate quality of life and functional capacity improvements of swine treated with the graft, and 3) Evaluate long term safety of the graft. Hypothesis: An engineered tissue comprised of differentiated cardiac myocytes and fibroblasts will effectively integrate into the host tissue, and restore cardiac function in swine with CHF. Methods: Male Yucatan mini swine 30-40kg were infarcted using percutaneous methods. Balloon occlusions (90 minute) are performed via catheter, distal to the first diagonal branch of the left anterior descending (LAD) coronary artery and animals. Four weeks after myocardial infarction (MI) cardiac grafts engineered with bio absorbable knitted mesh are implanted on the infarcted epicardium. Cardiac magnetic resonance imaging (MRI) is performed prior to MI, 1 month after MI, 1 month after patch placement, again at 3 month and 6 months. All swine are implanted with continuous event recorders to acquire surface electrocardiogram during the entire study. In addition, quality of life/functional capacity are assessed using FitBark collar activity monitors and treadmill exertion testing. Infarct size is determined using MRI images and 2,3,5-triphenyltetrazolium chloride staining at study end. Results: Medium to large transmural infarcts are generated with 90min balloon occlusion of the LAD which demonstrate compensatory remodeling of the LV as assessed via cardiac MRI. Upscale cardiac matrix grafts to 6cm diameter are easily handled by the surgeon and can be surgically implanted on the epicardium using sub-xiphoid median sternotomy. No adverse arrhythmic activity has been observed. Conclusion: Our cardiac graft is well suited for upscale to clinical size, can be easily handled and implanted in a swine model of CHF.

A Simple Method to Measure Renal Function in Swine by the Plasma Clearance of Iohexol.

There is no simple method to measure glomerular filtration rate (GFR) in swine, an established model for studying renal disease. We developed a protocol to measure GFR in conscious swine by using the plasma clearance of iohexol. We used two groups, test and validation, with eight animals each. Ten milliliters of iohexol (6.47 g) was injected into the marginal auricular vein and blood samples (3 mL) were collected from the orbital sinus at different points after injection. GFR was determined using two models: two-compartment (CL2: all samples) and one-compartment (CL1: the last six samples). In the test group, CL1 overestimated CL2 by ~30%: CL2 = 245 ± 93 and CL1 = 308 ± 123 mL/min. This error was corrected by a first-order polynomial quadratic equation to CL1, which was considered the simplified method: SM = −47.909 + (1.176xCL1) − (0.00063968xCL12). The SM showed narrow limits of agreement with CL2, a concordance correlation of 0.97, and a total deviation index of 14.73%. Similar results were obtained for the validation group. This protocol is reliable, reproducible, can be performed in conscious animals, uses a single dose of the marker, and requires a reduced number of samples, and avoids urine collection. Finally, it presents a significant improvement in animal welfare conditions and handling necessities in experimental trials.

Expression of integrin-linked kinase improves cardiac function in a swine model of myocardial infarction.

Previous studies have described the beneficial effects of overexpressing integrin-linked kinase (ILK) after myocardial infarction (MI) in small animal models. However, the effects of ILK in pre-clinical large animals are not known. To move closer to clinical translation, we examined the effects of ILK gene transfer in a swine model of ischemic heart disease. Swine received percutaneous intracoronary injections of adenoviral vector expressing ILK (n=10) or empty ad-null (n=10) in the left anterior descending coronary artery (LAD) following LAD occlusion. Four weeks after transfection, we confirmed that transgene expression was restricted to the infarcted area in the cardiac tissue. Imaging studies demonstrated preserved cardiac function in the ILK group. ILK treatment was associated with reduced infarcted scar size and preserved left ventricular (LV) geometry (LV diameter and LV wall thickness). Enhanced angiogenesis was preserved in the ILK animals, along with reduction of apoptosis. ILK gene therapy improves cardiac remodeling and function in swine following MI associated with increased angiogenesis, reduced apoptosis, and increased cardiomyocyte proliferation with no signs of toxicity. These results may deliver a new approach to treat post-infarct remodeling and subsequent heart failure.

Effects of different fluid resuscitation program on renal function in swine during shock stage of severe burn

Effects of different fluid resuscitation program on renal function in swine during shock stage of severe burn

1090 Lipopolysaccharide exposure in swine alters ovarian toll-like receptor 4 expression

Heat stress (HS) is associated with decreased fertility and endotoxemia as evidenced by increased systemic lipopolysaccharide (LPS) arising from decreased intestinal integrity. Across multiple species, LPS is associated with reduced female fecundity; phenotypic responses similar to HS-induced infertility, including spontaneous abortion and increased wean-to-estrus interval length. LPS binds to toll-like receptor 4 (TLR4), a membrane bound receptor, to initiate a signaling cascade culminating in the phosphorylation of nuclear factor kappa-B (pNFκB) and pro-inflammatory cytokine production. Acyloxyacyl hydrolase (AOAH) participates in LPS detoxification by cleaving the lipid A moiety, rendering the deacylated LPS unable to effectively bind TLR4. We hypothesized that endotoxemia could impact ovarian function in swine. Post-pubertal gilts were synchronized to the follicular phase of their estrous cycle using Matrix® administered orally for 14 d. Immediately following Matrix® removal, gilts were treated with vehicle control (CT; 3 mL sterile saline; n = 6) or LPS (0.1 μg/kg BW; E. coli 055:B5; n = 6) via jugular catheter four times daily (0000, 0600, 1200, 1800 h) for 5 d during the follicular phase preceding estrus. Six hours after the final LPS infusion, animals were euthanized and ovaries collected. Whole ovarian protein homogenates were prepared and western blotting performed to quantify abundance of TLR4 and AOAH protein. Relative to CT, ovaries from LPS treated gilts had reduced (P < 0.05) abundance of TLR4 protein. No effect (P > 0.05) of LPS infusion on AOAH abundance was observed. These data demonstrate that the ovary to be responsive to chronic, low-level LPS exposure, and that endotoxemia potentially contributes to seasonal infertility in swine. Funded by the Global Food Security Consortium.

Normal electrocardiographic and echocardiographic (M-mode and two-dimensional) values in Polish Landrace pigs.

BackgroundSwine are recognized animal models of human cardiovascular diseases. Normal values of cardiac morphology and function have been published for swine but for smaller number of pigs and not for swine whose weights ranged up 100 kg. In order to improve the value of results of an investigation on cardiac morphology and function in swine when such data are extrapolated to humans, the aim of this study was to document electrocardiographic and echocardiographic measures of cardiac morphology and function in swine. The study comprised 170 single and repeated measurements that were made in 132 healthy domestic swine (Sus domesticus) whose weights ranged between 20-160 kg and were used as controls in three different experiments. All electrocardiographic and echocardiographic measurements in all swine were done under general anaesthesia.ResultsStatistically significant correlations were found between body weight and heart rate (HR), the duration of the P-wave, the duration of the QRS interval, the duration of the QT interval, and the corrected QT ratio (QTc). Since body weight was positively correlated with age, statistically significant correlations were also found between age and HR, the duration of the P-wave, the duration of the QRS interval, the duration of the QT interval, and the QTc. We found that the thickness of the left ventricular wall and the internal diameter of the left ventricle increased with age and body weight. We also found positive trends between body weight and ejection fraction and body weight and fractional shortening. We also found a positive relationship between age, body weight, and the ratio of the left ventricular internal diameter to its wall thickness, as well as the relative left atrial size.ConclusionMany electro- and echocardiographic measures of cardiac morphology and function of healthy swine are related to their body weight. When the electro- and echocardiographic measures of domestic swine and humans are compared, the most comparable electrocardiographic values are those that were determined in swine whose body weights are not greater than 70 kg. In contrast, the most comparable echocardiographic measures are those that were determined in swine with a body weight of 40–110 kg.

Abstract 185: Global Infusion of Allogeneic Cardiosphere-Derived Cells Proportionally Stimulates Angiogenesis and Myocyte Regeneration in Swine With Chronic Myocardial Infarction

Background: Previously we reported that global infusion of CDCs in infarcted and non-infarcted remote regions improved LV function in swine with chronic myocardial infarction. The effect of global infusion of CDCs on angiogenesis and myocyte regeneration in infarcted and non-infarcted remote regions is unknown. Methods: Swine (n=11) with chronic infarction in the left anterior descending (LAD) coronary artery region were studied 8 weeks after microsphere embolization (1x10^6 particles, 45μm diameter). CDCs were isolated from myocardial atrium and 20 x 10^6 CDCs were infused into the 3 major coronary distributions after cyclosporine (100mg/day) immunosuppression. Data were compared to untreated animals. To assess the factors related to angiogenesis, VEGF and SDF-1 expression on cultured CDCs were quantified by RT-PCR. Angiogenesis was quantified by assessing capillary density (von Willebrand Factor) with immunohistochemistry. Myocyte regeneration was quantified by assessing myocyte nuclear density. The ratio of capillary density to myocyte nuclear density was evaluated. Results: icCDCs improved infarcted LAD (13±6 vs. 36±6%, p&lt;0.05) and remote (47±8 vs. 99±10%, p&lt;0.05) wall thickening with increased ejection fraction (32±3 vs. 45±4%, p&lt;0.05) compared to untreated. RT- PCR from cultured CDCs showed VEGF expression and to a less extent SDF-1 expression. icCDCs increased capillary density and myocyte nuclear density in infarcted LAD and remote regions by 40% (Table). Thus, the ratio of capillary density to myocyte nuclear density was maintained in untreated and icCDCs animals. Conclusion: These data indicate that in a model of infarction, global infusion of icCDCs stimulates angiogenesis and myocyte regeneration to the same extent in infarcted and non-infarcted regions resulting in improved global function. Thus, global infusion of icCDCs may afford a widely available approach to regenerate myocardium in patients with ischemic cardiomyopathy.

Eprosartan improves cardiac function in swine working heart model of ischemia-reperfusion injury.

BackgroundEprosartan is an angiotensin II receptor antagonist used as an antihypertensive. We sought to evaluate the regional effect of Eprosartan on postinfarct ventricular remodeling and myocardial function in an isolated swine working heart model of ischemia-reperfusion injury.Material/Methods22 swine hearts were perfused with the Langendorff perfusion apparatus under standard experimental conditions. Myocardial ischemia was induced by a 10-min left anterior descending artery ligation. Hearts were reperfused with either saline (control group, n=11), or Eprosartan (treatment group, n=11). Left ventricular pressure (LVP) and regional heart parameters such as intramyocardial pressure (IMP), wall thickening rate (WTh), and pressure-length-loops (PLL) were measured at baseline and after 30 min of reperfusion.ResultsMeasured parameters were statistically similar between the 2 groups at baseline. The administration of Eprosartan led to a significantly better recovery of IMP and WTh: 44.4±2.5 mmHg vs. 51.2±3.3 mmHg, p<0.001 and 3.8±0.4 μm vs. 4.4±0.3 μm, p=0.001, respectively. PLL were also significantly higher in the treatment group following reperfusion (21694±3259 units vs. 31267±3429 units, p<0.01). There was no difference in the LVP response to Eprosartan versus controls (63.6±3.0 mmHg vs. 62.5±3.1 mmHg, p=0.400).ConclusionsPre-treatment with Eprosartan is associated with a significant improvement in regional cardiac function under ischemic conditions. Pharmacological treatment with eprosartan may exert a direct cardioprotective effect on ischemic myocardium.