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27 result(s) for "Gura, Kathleen M."
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Alpha-tocopherol in intravenous lipid emulsions imparts hepatic protection in a murine model of hepatosteatosis induced by the enteral administration of a parenteral nutrition solution
Intestinal failure-associated liver disease (IFALD) is a risk of parenteral nutrition (PN)-dependence. Intravenous soybean oil-based parenteral fat can exacerbate the risk of IFALD while intravenous fish oil can minimize its progression, yet the mechanisms by which soybean oil harms and fish oil protects the liver are uncertain. Properties that differentiate soybean and fish oils include α-tocopherol and phytosterol content. Soybean oil is rich in phytosterols and contains little α-tocopherol. Fish oil contains abundant α-tocopherol and little phytosterols. This study tested whether α-tocopherol confers hepatoprotective properties while phytosterols confer hepatotoxicity to intravenous fat emulsions. Utilizing emulsions formulated in the laboratory, a soybean oil emulsion (SO) failed to protect from hepatosteatosis in mice administered a PN solution enterally. An emulsion of soybean oil containing α-tocopherol (SO+AT) preserved normal hepatic architecture. A fish oil emulsion (FO) and an emulsion of fish oil containing phytosterols (FO+P) protected from steatosis in this model. Expression of hepatic acetyl CoA carboxylase (ACC) and peroxisome proliferator-activated receptor gamma (PPARγ), was increased in animals administered SO. ACC and PPARγ levels were comparable to chow-fed controls in animals receiving SO+AT, FO, and FO+P. This study suggests a hepatoprotective role for α-tocopherol in liver injury induced by the enteral administration of a parenteral nutrition solution. Phytosterols do not appear to compromise the hepatoprotective effects of fish oil.
Inflammation drives pathogenesis of early intestinal failure-associated liver disease
Patients with intestinal failure who receive long-term parenteral nutrition (PN) often develop intestinal failure-associated liver disease (IFALD). Although there are identified risk factors, the early pathogenesis is poorly understood and treatment options are limited. Here, we perform a transcriptomic analysis of liver tissue in a large animal IFALD model to generate mechanistic insights and identify therapeutic targets. Preterm Yorkshire piglets were provided PN or bottle-fed with sow-milk replacer for 14 days. Compared to bottle-fed controls, piglets receiving PN developed biochemical cholestasis by day of life 15 (total bilirubin 0.2 vs. 2.9 mg/dL, P  = 0.01). RNA-Seq of liver tissue was performed. Ingenuity Pathway Analysis identified 747 differentially expressed genes (343 upregulated and 404 downregulated) with an adjusted P  < 0.05 and a fold-change of > |1|. Enriched canonical pathways were identified, demonstrating broad activation of inflammatory pathways and inhibition of cell cycle progression. Potential therapeutics including infliximab, glucocorticoids, statins, and obeticholic acid were identified as predicted upstream master regulators that may reverse the PN-induced gene dysregulation. The early driver of IFALD in neonates may be inflammation with an immature liver; identified therapeutics that target the inflammatory response in the liver should be investigated as potential treatments.
Fat digestion using RELiZORB in children with short bowel syndrome who are dependent on parenteral nutrition: Protocol for a 90-day, phase 3, open labeled study
Short bowel syndrome (SBS) is a leading cause of intestinal failure resulting in parenteral nutrition (PN) dependence and nutritional deficiencies. Long-term PN use is associated with the development of sepsis and intestinal failure-associated liver disease. Achieving enteral autonomy is the optimal way to prevent these complications. In SBS, the decreased intestinal length, bile acid deficiency, and rapid transit time contribute to fat malabsorption and continued PN dependence. We propose the use of an immobilized lipase cartridge (ILC; RELiZORB) that connects in-line with enteral feed tubing sets and is designed to breakdown the majority of fats provided in enteral nutrition (EN). Preclinical studies have demonstrated both improved fat and fat-soluble vitamin absorption with ILC use in a porcine model of SBS. To evaluate the clinical applicability of these findings, we designed a phase 3, open labeled, single center, clinical trial to determine the safety, tolerability, and efficacy of the RELiZORB enzyme cartridge when used daily with EN for 90 days. The patient population will include PN dependent children with SBS, aged 2-18 years. The primary outcome is the change in PN calories from baseline, assessed weekly throughout the study. Changes in growth Z-scores, 72-hour fecal fat and coefficient of fat absorption, plasma fatty acids and fat-soluble vitamins will also be evaluated. Assessment of change in continuous outcomes will be made using the area under the curve, expressed as a percent change relative to baseline, calculated over study day 7 to 90 (AUC7-90). The incidence of adverse events will be monitored and summarized by system organ class. If successful, RELiZORB may offer a safe alternative to reducing PN dependence and achieving enteral autonomy in pediatric intestinal failure. These results would be clinically significant given the clear association between long-term PN use and complications in SBS. ClinicalTrials.gov NCT03530852; registered on May 21st, 2018, last update posted on September 14th, 2022.
A medium-chain fatty acid analogue prevents endotoxin liver injury in a murine model
Parenteral nutrition (PN) is lifesaving for patients with short bowel syndrome and other gastrointestinal disorders, however long-term use may lead to complications including hepatosteatosis and sepsis. We have previously demonstrated the anti-steatotic, -fibrotic, and -inflammatory properties of SEFA-6179, an engineered medium-chain fatty acid analogue. We hypothesized that SEFA-6179 treatment would protect against endotoxin-induced liver injury in a murine model of PN-induced hepatosteatosis. C57Bl/6J mice were administered a high-carbohydrate liquid diet plus intravenous lipid emulsion (Intralipid, 4 g fat/kg/d) or intravenous saline for 19 days to induce hepatosteatosis. SEFA-6179 (100 mg/kg) or vehicle (MCT/medium-chain triglyceride) was administered via oral gavage for four days leading up to intraperitoneal challenge with lipopolysaccharide (15 mg/kg) or saline on day 19. Age-matched, chow-fed controls received the same treatments. The primary outcome was liver biomarkers: alanine aminotransferase and aspartate aminotransferase. Pro-inflammatory cytokines, IL-6, TNF-alpha, and monocyte chemoattractant protein (MCP1), were analyzed. Liver immunofluorescence staining was performed to evaluate macrophage phenotypes. In endotoxin-challenged mice, pre-treatment with SEFA-6179 lowered liver enzymes and pro-inflammatory cytokine levels compared to vehicle. On liver histology, SEFA-6179 pre-treatment led to greater polarization of M1/pro-inflammatory macrophages to an M2/anti-inflammatory phenotype compared to vehicle. SEFA-6179 is currently in Phase II clinical trials. These findings support the potential application of SEFA-6179 in high-risk, PN-dependent patients.
Direct thrombin inhibitors as alternatives to heparin to preserve lung growth and function in a murine model of compensatory lung growth
Infants with congenital diaphragmatic hernia (CDH) may require cardiopulmonary bypass and systemic anticoagulation. Expeditious lung growth while on bypass is essential for survival. Previously, we demonstrated that heparin impairs lung growth and function in a murine model of compensatory lung growth (CLG). We investigated the effects of the direct thrombin inhibitors (DTIs) bivalirudin and argatroban. In vitro assays of lung endothelial cell proliferation and apoptosis were performed. C57BL/6 J mice underwent left pneumonectomy and subcutaneous implantation of osmotic pumps. Pumps were pre-loaded with normal saline (control), bivalirudin, argatroban, or heparin and outcomes were assessed on postoperative day 8. Heparin administration inhibited endothelial cell proliferation in vitro and significantly decreased lung volume in vivo, while bivalirudin and argatroban preserved lung growth. These findings correlated with changes in alveolarization on morphometric analysis. Treadmill exercise tolerance testing demonstrated impaired exercise performance in heparinized mice; bivalirudin/argatroban did not affect exercise tolerance. On lung protein analysis, heparin decreased angiogenic signaling which was not impacted by bivalirudin or argatroban. Together, this data supports the use of DTIs as alternatives to heparin for systemic anticoagulation in CDH patients on bypass. Based on this work, clinical studies on the impact of heparin and DTIs on CDH outcomes are warranted.
A medium-chain fatty acid analogue prevents hepatosteatosis and decreases inflammatory lipid metabolites in a murine model of parenteral nutrition-induced hepatosteatosis
Parenteral (intravenous) nutrition is lifesaving for patients with intestinal failure, but long-term use of parenteral nutrition often leads to liver disease. SEFA-6179 is a synthetic medium-chain fatty acid analogue designed to target multiple fatty acid receptors regulating metabolic and inflammatory pathways. We hypothesized that SEFA-6179 would prevent hepatosteatosis and lipotoxicity in a murine model of parenteral nutrition-induced hepatosteatosis. Two in vivo experiments were conducted. In the first experiment, six-week-old male mice were provided an ad lib fat-free high carbohydrate diet (HCD) for 19 days with orogastric gavage of either fish oil, medium-chain triglycerides, or SEFA-6179 at a low (0.3mmol/kg) or high dose (0.6mmol/kg). In the second experiment, six-week-old mice were provided an ad lib fat-free high carbohydrate diet for 19 days with every other day tail vein injection of saline, soybean oil lipid emulsion, or fish oil lipid emulsion. Mice then received every other day orogastric gavage of medium-chain triglyceride vehicle or SEFA-6179 (0.6mmol/kg). Hepatosteatosis was assessed by a blinded pathologist using an established rodent steatosis score. Hepatic lipid metabolites were assessed using ultra-high-performance liquid chromatography-mass spectrometry. Effects of SEFA-6179 on fatty acid oxidation, lipogenesis, and fatty acid uptake in human liver cells were assessed in vitro. In the first experiment, mice receiving the HCD with either saline or medium-chain triglyceride treatment developed macrovesicular steatosis, while mice receiving fish oil or SEFA-6179 retained normal liver histology. In the second experiment, mice receiving a high carbohydrate diet with intravenous saline or soybean oil lipid emulsion, along with medium chain triglyceride vehicle treatment, developed macrovescular steatosis. Treatment with SEFA-6179 prevented steatosis. In each experiment, SEFA-6179 treatment decreased arachidonic acid metabolites as well as key molecules (diacylglycerol, ceramides) involved in lipotoxicity. SEFA-6179 increased both β- and complete fatty oxidation in human liver cells, while having no impact on lipogenesis or fatty acid uptake. SEFA-6179 treatment prevented hepatosteatosis and decreased toxic lipid metabolites in a murine model of parenteral nutrition-induced hepatosteatosis. An increase in both β- and complete hepatic fatty acid oxidation may underlie the reduction in steatosis.
IMPOWER: a national patient-generated registry for intestinal malrotation exploring diagnosis, treatment, and surgical outcomes
Background Intestinal malrotation is a rare congenital condition with potentially devastating consequences due to potential volvulus and massive intestinal necrosis. Diagnosis is often delayed and long-term symptoms following surgical correction are poorly characterized. We developed the I ntestinal Malrotation Patient Outcomes and WEllness Registry (IMPOWER), a national patient-generated registry (PGR), to capture data related to presenting symptoms, testing, diagnosis, treatment, and follow-up of individuals diagnosed with malrotation. IMPOWER captures patient-reported information from adult patients and parents/caregivers of children diagnosed with malrotation at the time of enrollment and at ongoing 6-month intervals. We present baseline characteristics of patients enrolled during the first two months of the registry. Results Within the first two months, 354 patients with malrotation enrolled in IMPOWER, and 191 (53.9%) completed all baseline assessments. Nearly 90% of the 119 pediatric participants and 37.7% of the 72 adult participants experienced symptoms prior to diagnosis. Vomiting was the predominant symptom for pediatric participants compared to abdominal pain in adults. Yellow bilious emesis was more commonly reported than green, and volvulus at diagnosis occurred in 70% of pediatric and 27% of adult participants. One-third of pediatric participants had a bowel resection as part of their initial surgical procedure, resulting in 23.4% with diagnosed short bowel syndrome. More than 60% of pediatric and 80% of adult registrants reported gastrointestinal symptoms that persisted throughout the first year following their initial operation. Approximately 25% of registrants reported visiting four or more gastroenterologists for management of ongoing symptoms. Conclusions Fewer than half of pediatric patients presented with the “classic” presentation of green bilious colored emesis. Yellow bilious emesis was more commonly reported, and chronic gastrointestinal symptoms (i.e., abdominal pain, reflux, constipation, diarrhea) and feeding intolerance were common following surgical procedures for malrotation. This novel PGR highlights the need for a multicenter prospective registry to characterize the natural history and develop consistent standards of care related to the diagnosis, treatment, and long-term care for patients with malrotation.
Aluminum contamination in products used in parenteral nutrition: Has anything changed?
In July 2004, the U.S. Food and Drug Administration issued a mandate that required manufacturers to include the aluminum content on the labels of the additives commonly used in the compounding of parenteral nutrition solutions. It was the hope that practitioners would use this information to minimize the amount of aluminum exposure provided by parenteral nutrition to less than the 5 mCg/kg/d, the threshold deemed as “safe.” Since that time, it has been difficult to easily incorporate these guidelines into clinical practice due to limitations in current product formulations. The purpose of this article is to revisit the rationale for the development of this mandate and to survey the literature since its implementation to determine if any new findings have emerged. A brief overview of aluminum toxicity, the patient populations at risk, treatment options, and compounding considerations is also presented.
A Diet With Docosahexaenoic and Arachidonic Acids as the Sole Source of Polyunsaturated Fatty Acids Is Sufficient to Support Visual, Cognitive, Motor, and Social Development in Mice
Polyunsaturated fatty acids serve multiple functions in neurodevelopment and neurocognitive function. Intravenous lipid emulsions are administered to children that are dependent on parenteral nutrition to provide the essential fatty acids needed to sustain growth and development. One of these emulsions, derived from fish-oil, is particularly poor in the traditional essential fatty acids, linoleic and alpha-linolenic acids. However, it does contain adequate amounts of its main derivatives, arachidonic acid (ARA) and docosahexaenoic acid (DHA), respectively. This skewed composition has raised concern about the sole use of fish-oil based lipid emulsions in children and how its administration can be detrimental to their neurodevelopment. Using a custom-made diet that contains ARA and DHA as a sole source of polyunsaturated fatty acids, we bred and fed mice for multiple generations. Compared to adult, chow-fed mice, animals maintained on this special diet showed similar outcomes in a battery of neurocognitive tests performed under controlled conditions. Chow-fed mice did perform better in the rotarod test for ataxia and balance, although both experimental groups showed a conserved motor learning capacity. Conversely, mice fed the custom diet rich in DHA and ARA showed less neophobia than the chow-fed animals. Results from these experiments suggest that providing a diet where ARA and DHA are the sole source of polyunsaturated fatty acids is sufficient to support gross visual, cognitive, motor, and social development in mice.
A Metabolomic Analysis of Two Intravenous Lipid Emulsions in a Murine Model
Parenteral nutrition (PN), including intravenous lipid administration, is a life-saving therapy but can be complicated by cholestasis and liver disease. The administration of intravenous soy bean oil (SO) has been associated with the development of liver disease, while the administration of intravenous fish oil (FO) has been associated with the resolution of liver disease. The biochemical mechanism of this differential effect is unclear. This study compares SO and FO lipid emulsions in a murine model of hepatic steatosis, one of the first hits in PN-associated liver disease. We established a murine model of hepatic steatosis in which liver injury is induced by orally feeding mice a PN solution. C57BL/6J mice were randomized to receive PN alone (a high carbohydrate diet (HCD)), PN plus intravenous FO (Omegaven®; Fresenius Kabi AG, Bad Homburg VDH, Germany), PN plus intravenous SO (Intralipid®; Fresenius Kabi AG, Bad Homburg v.d.H., Germany, for Baxter Healthcare, Deerfield, IL), or a chow diet. After 19 days, liver tissue was harvested from all animals and subjected to metabolomic profiling. The administration of an oral HCD without lipid induced profound hepatic steatosis. SO was associated with macro- and microvesicular hepatic steatosis, while FO largely prevented the development of steatosis. 321 detectable compounds were identified in the metabolomic analysis. HCD induced de novo fatty acid synthesis and oxidative stress. Both FO and SO relieved some of the metabolic shift towards de novo lipogenesis, but FO offered additional advantages in terms of lipid peroxidation and the generation of inflammatory precursors. Improved lipid metabolism combined with reduced oxidative stress may explain the protective effect offered by intravenous FO in vivo.