A Medium-Chain Fatty Acid Analogue Prevents Intestinal Failure-Associated Liver Disease in Preterm Yorkshire Piglets.

BACKGROUND & AIMS: At least 20%-30% of patients with intestinal failure receiving long-term parenteral nutrition will develop intestinal failure-associated liver disease (IFALD), for which there are few therapeutic options. SEFA-6179 is a first-in-class structurally engineered medium-chain fatty acid analogue that acts through GPR84, PPARα, and PPARγ agonism. We hypothesized that SEFA-6179 would prevent biochemical and histologic liver injury in a preterm piglet model of IFALD. METHODS: Preterm Yorkshire piglets were delivered by cesarean section, and parenteral nutrition was provided for 14 days via implanted central venous catheters. Animals were treated with either medium-chain triglyceride vehicle control or SEFA-6179. RESULTS: Compared to medium-chain triglyceride vehicle at day of life 15, SEFA-6179 prevented biochemical cholestasis (direct bilirubin: 1.9 vs <0.2 mg/dL, P = .01; total bilirubin: 2.7 vs 0.4 mg/dL, P = .02; gamma glutamyl transferase: 172 vs 30 U/L, P = .01). SEFA-6179 also prevented steatosis (45.6 vs 13.9 mg triglycerides/g liver tissue, P = .009), reduced bile duct proliferation (1.6% vs 0.5% area cytokeratin 7 positive, P = .009), and reduced fibrosis assessed by a masked pathologist (median Ishak score: 3 vs 1, P = 0.007). RNA sequencing of liver tissue demonstrated that SEFA-6179 broadly impacted inflammatory, metabolic, and fibrotic pathways, consistent with its in vitro receptor activity (GPR84/PPARα/PPARγ agonist). CONCLUSIONS: In a preterm piglet model of IFALD, SEFA-6179 treatment prevented biochemical cholestasis and steatosis and reduced bile duct proliferation and fibrosis. SEFA-6179 is a promising first-in-class therapy for the prevention and treatment of IFALD that will be investigated in an upcoming phase II clinical trial.

Outcomes and Perioperative Nutritional Management in a Porcine Model of Short Bowel Syndrome.

INTRODUCTION: Short bowel syndrome (SBS) results from significant intestinal loss and is characterized by insufficient absorption of nutrients and fluids. Preclinical large animal SBS models typically require parenteral nutrition (PN) support and may not be appropriate for studying interventions to improve intestinal absorption or adaptation. Here, we describe the development of a porcine SBS model that does not require PN support. METHODS: Eight male Yorkshire piglets underwent either a 75% or 90% jejunoileal resection (n = 5) or no resection (n = 3). Continuous enteral nutrition (EN) was provided via a gastrostomy tube. The final SBS model consisted of a 75% resection and nutrition provided via combination EN (60%) and per oral pig chow (40%). Body weight and concentration of fat-soluble vitamins were assessed on postoperative days (POD) 7, 14, and 21. For assessing fat malabsorption, the coefficient of fat absorption (CFA) was calculated following a 72-h stool collection. RESULTS: Resected animals had decreased weight gain compared to unresected controls (POD21 + 8.3% versus +28.8%, P = 0.048). Vitamin D concentration was significantly lower in resected animals compared to controls on POD 7, POD 14, and POD 21. Serum vitamin E concentration was also lower on POD 21. Resected animals developed fat malabsorption with lower CFA (76.5% versus 95.3%, P = 0.014). CONCLUSIONS: We describe the development of a porcine SBS model that does not require PN support. Piglets in this model gain less weight, demonstrate fat malabsorption, and develop fat-soluble vitamin deficiencies. This model will benefit investigations of intestinal absorption or adaptation while potentially decreasing costs and confounding complications related to PN administration.

Perioperatively Inhaled Hydrogen Gas Diminishes Neurologic Injury Following Experimental Circulatory Arrest in Swine.

This study used a swine model of mildly hypothermic prolonged circulatory arrest and found that the addition of 2.4% inhaled hydrogen gas to inspiratory gases during and after the ischemic insult significantly decreased neurologic and renal injury compared with controls. With proper precautions, inhalational hydrogen may be administered safely through conventional ventilators and may represent a complementary therapy that can be easily incorporated into current workflows. In the future, inhaled hydrogen may diminish the sequelae of ischemia that occurs in congenital heart surgery, cardiac arrest, extracorporeal life-support events, acute myocardial infarction, stroke, and organ transplantation.

Vascular Endothelial Growth Factor Enhances Compensatory Lung Growth in Piglets.

BACKGROUND: Vascular endothelial growth factor has been found to accelerate compensatory lung growth after left pneumonectomy in mice. The aim of this study was to determine the natural history and the effects of vascular endothelial growth factor on compensatory lung growth in a large animal model. METHODS: To determine the natural history of compensatory lung growth, female Yorkshire piglets underwent a left pneumonectomy on days of life 10-11. Tissue harvest and volume measurement of the right lung were performed at baseline (n = 5) and on postoperative days 7 (n = 5), 14 (n = 4), and 21 (n = 5). For pharmacokinetic studies, vascular endothelial growth factor was infused via a central venous catheter, with plasma vascular endothelial growth factor levels measured at various time points. To test the effect of vascular endothelial growth factor on compensatory lung growth, 26 female Yorkshire piglets underwent a left pneumonectomy followed by daily infusion of vascular endothelial growth factor at 200 µg/kg or isovolumetric 0.9% NaCl (saline control). Lungs were harvested on postoperative day 7 for volume measurement and morphometric analyses. RESULTS: Compared with baseline, right lung volume after left pneumonectomy increased by factors of 2.1 ± 0.6, 3.3 ± 0.6, and 3.6 ± 0.4 on postoperative days 7, 14, and 21, respectively. The half-life of VEGF ranged from 89 to 144 minutes. Lesser doses of vascular endothelial growth factor resulted in better tolerance, volume of distribution, and clearance. Compared with the control group, piglets treated with vascular endothelial growth factor had greater lung volume (P < 0.0001), alveolar volume (P = 0.001), septal surface area (P = 0.007) and total alveolar count (P = 0.01). CONCLUSION: Vascular endothelial growth factor enhanced alveolar growth in neonatal piglets after unilateral pneumonectomy.

Technique and perioperative management of left pneumonectomy in neonatal piglets.

BACKGROUND: Although commonly performed in adult swine, unilateral pneumonectomy in piglets requires significant modifications in the surgical approach and perioperative care because of their smaller size and limited physiological reserve. METHODS: Nineteen neonatal piglets underwent a left pneumonectomy. They were allowed 5-7 d of preoperative acclimation and nutritional optimization. Preoperative weight gain and laboratory values were obtained before the time of surgery. A "ventro-cranial" approach is adopted where components of the pulmonary hilum were sequentially identified and ligated, starting from the most ventral and cranial structure, the superior pulmonary vein. The principle of gentle ventilation was followed throughout the entire operation. RESULTS: The median age of the piglets at the time of surgery was 12 (10-12) d. The median preoperative weight gain and albumin level were 20% (16-26%) and 2.3 (2.1-2.4) g/dL, respectively. The median operative time was 59 (50-70) min. Five of the first nine piglets died from complications, two from poor preoperative nutritional optimization (both with <10% weight gain and 2 g/dL for albumin), one from an intubation complication, one from intra-operative bleeding, and one in the postoperative period from a ruptured bulla. No mortality occurred for the next 10 cases. CONCLUSIONS: Successful outcomes for unilateral pneumonectomy in piglets require special attention to preoperative nutritional optimization, gentle ventilation, and meticulous surgical dissection. Preoperative weight gain and albumin levels should be used to identify appropriate surgical candidates. The "ventro-cranial" approach allows for a technically straightforward completion of the procedure.

Evaluation of anastomotic strength and drug safety after short-term sunitinib administration in rabbits.

BACKGROUND: Sunitinib (Sutent) is a Food and Drug Administration-approved receptor tyrosine kinase inhibitor found to reduce postoperative adhesion formation in animal models. The objective of the present study was to evaluate anastomotic healing and potential drug-related toxicities after short-term sunitinib administration in New Zealand White rabbits. MATERIALS AND METHODS: Under an approved study protocol, 40 rabbits underwent a laparotomy followed by colonic transection and anastomosis. Animals were randomly assigned to treatment with oral sunitinib (10 mg/kg/d) or placebo, received one preoperative dose followed by 10 postoperative doses, and were divided into two groups following the procedure: group I animals were euthanized on completion of drug treatment and group II animals were euthanized 30 d after completion of treatment. Prior to study completion, animals underwent an echocardiogram and laboratory test results were obtained. At necropsy, intestinal bursting strength (in mmHg) was evaluated. RESULTS: All animals survived until designated euthanasia. There was no evidence of intra-abdominal sepsis or intestinal obstruction. Sunitinib-treated animals were found to have lower intestinal anastomotic strength compared with placebo-treated animals, as measured by bursting pressure at euthanasia, and a greater percentage of bursting at the anastomosis. On echocardiography, all ejection and shortening fractions were within established normal reference values. There were no significant differences in liver enzymes between animals. There were no wound infections, dehiscence, or delayed wound healing in any animal. CONCLUSIONS: These results caution against the administration of sunitinib in cases involving intestinal anastomoses because of the elevated risk of anastomotic leak. No evidence of cardiotoxicity, hepatotoxicity, or detrimental effect on wound healing was found in any animal.

Sunitinib reduces recurrent pelvic adhesions in a rabbit model.

BACKGROUND: Adhesions represent a major problem after abdominal and pelvic procedures. The purpose of the present study was to determine the effect of sunitinib (Sutent, SU11248), a Food and Drug Administration-approved receptor tyrosine kinase inhibitor, on recurrent pelvic adhesion formation after pelvic adhesiolysis in a rabbit model. MATERIALS AND METHODS: A total of 20 New Zealand white rabbits underwent a uterine abrasion procedure, followed by an adhesiolysis procedure 4 weeks later. Before adhesiolysis, the rabbits were randomized to sunitinib at 10 mg/kg/d or placebo. These were administered as 1 dose preoperatively followed by 10 doses postoperatively. The rabbits were killed 30 d after the adhesiolysis procedure. At death, the adhesions were scored, and a total adhesion score (presented as the median and interquartile range [IQR]) was calculated according to the percentage of uterine involvement and the tenacity of the adhesions. RESULTS: All the rabbits survived the operative procedures without complications. The sunitinib-treated rabbits (n = 10) had a significantly lower uterine involvement score (median 2.0, IQR 1.0-3.0) than the placebo-treated rabbits (median 4.0, IQR 3.0-4.0; P = 0.02). The sunitinib-treated rabbits also had median tenacity score of 3.0 (IQR 3.0-4.0) compared with a median of 4.0 (IQR 4.0-4.0; P = 0.04) in the placebo-treated rabbits (n = 10). The median total score in the sunitinib-treated rabbits was 5.0 (IQR 4.0-6.25) compared with 8.0 (IQR 6.75, 8.0) in the placebo-treated rabbits (P = 0.01). CONCLUSIONS: Sunitinib treatment might be an efficacious strategy to reduce recurrent adhesion formation after pelvic procedures.

Effect of sunitinib on functional reproductive outcome in a rabbit model.

OBJECTIVE: To determine the effect of sunitinib (Sutent; SU11248; Pfizer), a US Food and Drug Administration-approved receptor tyrosine kinase inhibitor previously shown to reduce de novo pelvic adhesion formation, on reproductive function after surgical uterine abrasion in a rabbit model. DESIGN: Randomized placebo-controlled study. SETTING: Large animal facility within an academic hospital. ANIMAL(S): Thirty New Zealand White adult female rabbits (2.2-3.0 kg). INTERVENTION(S): Administration of 11 doses (one preoperative and 10 postoperative) of oral sunitinib (10 mg/kg/d) or placebo. MAIN OUTCOME MEASURE(S): Effect of short-term postoperative sunitinib administration on reproductive function after surgical uterine abrasion. RESULT(S): All animals were impregnated and survived until designated euthanasia. Sunitinib-treated animals had a larger average litter size (7.7 ± 1.9 vs. 5.6 ± 2.7 kits) and offspring viability (7.1 ± 2.7 vs. 3.5 ± 3.2 kits) compared with placebo-treated animals. There was no difference in gestational length or aberration in the maintenance of fertility. There were no gross abnormalities, detectable birth defects, or growth disparity in offspring from sunitinib versus placebo-treated mothers. The adhesion burden identified at euthanasia after parturition was lower in sunitinib compared with placebo-treated animals (N = 10/group). CONCLUSION(S): Sunitinib ameliorated adhesion-induced reproductive aberrations after surgical uterine abrasion and may be an efficacious strategy to reduce postoperative pelvic adhesions.

Thoracic massage permits use of echocardiography in unanesthetized rats.

PURPOSE: The objective of the study reported here was to investigate whether massage-like stroking of the thorax and cranial portion of the abdomen might relax unanesthetized rats sufficiently to permit in vivo echocardiography. METHODS: Nine-month-old spontaneously hypertensive rats (SHR) were first conditioned to being held by hand for 10 to 15 min twice a day for seven to 10 days. During each session, the animal was placed in supine position, and the thorax and cranial abdominal area were gently stroked (approx. 5 cm/s, 12 to 14 times/min). After the conditioning period, echocardiography was initiated. We obtained serial transthoracic two-dimensional (2-D) and M-mode echocardiograms from nine-month-old SHR that were treated with isoproterenol (60 mg/kg of body weight, s.c., x 1, followed by 30 mg/kg/d x3), and from old (20 to 24 months old) SHR, studied when labored breathing, suggestive of heart failure, was evident (SHR-F). Measurements included end-diastolic volume (EDV) and end-systolic volume (ESV). RESULTS: In the isoproterenol-treated SHR, mean +/- SD echocardiographically derived EDV (2-D, 0.29 +/- 0.05; M-mode, 0.28 +/- 0.01 ml) was not significantly different from volume at necropsy (0.33 +/- 0.04 ml). Measurements of EDV and ESV by use of M-mode and 2-D echocardiography were significantly correlated (EDV R2 = 0.48, P = 0.05; ESV R2 = 0.39, P = 0.02). Echocardiography revealed pleuropericardial effusions (4/6), atrial thrombi (5/6), and left and right ventricular enlargement (6/6). The EDV and ESV were increased fivefold (P < 0.01) and threefold (P < 0.05), respectively, versus values for SHR not in heart failure (SHR-NF). Left ventricular ejection fraction of hearts from SHR-F was markedly decreased, compared with that in SHR-NF (44 +/- 7 versus 74 +/- 2%, respectively; P < 0.05). The presence or absence of left atrial thrombi and fluid in the thoracic cavity was confirmed at necropsy in SHR-F and SHR-NF. CONCLUSION: Thoracic massage permits use of echocardiography in unanesthetized rats, thereby providing a simple, non-invasive technique for assessment of cardiac structure and function in rats without the potentially adverse effects of anesthesia.