Infusion Of Emulsion Research Articles

Development and validation of samples stabilization strategy and LC-MS/MS method for simultaneous determination of clevidipine and its primary metabolite in human plasma: Application to clinical pharmacokinetic study in Chinese healthy volunteers

A feasible LC-MS/MS method with reliable stabilizers consisted of sodium fluoride, ascorbic acid and formic acid was developed and validated for the determination of clevidipine and its primary metabolite (H152/81) in human plasma. Sodium fluoride existing in the vacutainer tubes was used to inhibit esterase activity to protect the clevidipine from hydrolysis as soon as blood was collected. Ascorbic acid and formic acid were added to the separated plasma samples to avoid the oxidation and further hydrolysis of clevidipine and H152/81. The further sample preparation was accomplished through a single step liquid-liquid extraction (LLE) by ethyl acetate. The chromatography separation was carried out on an ACE Excel 3 μm SuperC18 (2.1 × 50 mm, id, ACE, United Kingdom) column with gradient elution using 10 mM ammonium acetate water solution and methanol as the mobile phase. Detection was performed in the negative ion electrospray ionization mode using multiple reaction monitoring (clevidipine: m/z 454.1 → 234.0; clevidipine-d7: m/z 461.1 → 240.1; H152/81: m/z 354.0 → 208.0; H152/81-13CD3: m/z 358.0 → 212.0). The method exhibited good linearity over the concentration ranges of 0.100 to 40.0 ng/mL for clevidipine and 5.00 to 400 ng/mL for H152/81. The intra- and inter-batch precision and accuracy of clevidipine and H152/81 were all within the acceptable criteria. The method was successfully applied to a pharmacokinetic study of clevidipine and H152/81 in healthy Chinese volunteers following 8 mg/h intravenous infusion of clevidipine butyrate injectable emulsion for 0.5 h. The results showed that clevidipine was rapidly eliminated with a short half-life time of 0.244 ± 0.125 h and a maximum concentration of 25.2 ± 7.09 ng/mL. H152/81 was detectable in the plasma samples up to 48.5 h with a half-life time of 10.7 ± 2.30 h and a maximum plasma concentration of 301 ± 38.1 ng/mL.

Increased myocardial fat supply improves cardiac energetics and function in heart failure

Abstract Introduction The failing heart is starved of energy, in part accounting for its contractile dysfunction. Reduced uptake of fat and sugar required for energy production has frequently been demonstrated in heart failure, therefore altering metabolism of glucose and/or fat is therefore attractive as a therapy. We hypothesized increasing glucose supply would be beneficial over increasing fat supply so measured ATP usage (via PCr/ATP ratio and flux through creatine kinase) and cardiac function during fat emulsion infusion or euglycaemic hyperinsulinaemic clamp. Methods 11 patients with a diagnosis of heart failure and nonischaemic cardiomyopathy were recruited, mean age 66 (range 49–80), mean BMI 27.7 (range 21.3–37.5), F:M 3:8, 3 diabetic and 8 non-diabetic. On the first visit they had a baseline cardiac magnetic resonance (CMR), collecting cardiac volumes and function, then were randomised to receive either fat infusion or euglycaemic clamp. Following an hour of infusion, CMR was repeated followed by 31P cardiac magnetic resonance spectroscopy, then a dobutamine stress sequence at 65% maximum heart rate. They received the alternate infusion at the next visit. Results Data was normally distributed. Baseline ejection fraction was 37±9%. PCr/ATP ratio was greater with the fat infusion compared to euglycaemic clamp (1.82±0.26 vs 1.68±0.24, p=0.04). Fat emulsion infusion also brought about a greater ejection fraction increase over the baseline, compared to the euglycaemic clamp in which there was little difference (+5.3±5.3% vs −0.6±3.1%, p=0.004). Calculated cardiac work was greater in the fat infusion group than the Insulin/glucose group (682±156 L.mmHg/min vs 581±85 L.mmHg/min, p=0.009). There was no significant difference in creatine kinase first order rate constant (fat infusion 0.2±0.09/s vs euglycaemic clamp 0.16±0.07/s, p=0.32) nor creatine kinase flux (fat infusion 1.85±0.92 μmol/g/s vs euglycaemic clamp 1.46±0.58 μmol/g/s, p=0.22). The increment in cardiac output on stress over baseline was not significantly different between arms (fat infusion +3.39±3.07 L/min vs euglycaemic clamp +3.08±2.57 L/min, p=0.42). The PCr/ATP ratio showed positive correlation with the stress ejection fraction (R2=0.656, p=0.001), but not with resting ejection fraction. Conclusions Increased supply of fat to the myocardium brought about improved contractility and cardiac energetics compared to an increased glucose supply. The increase in PCr/ATP ratio would imply (given ATP concentrations are kept constant in the myocardium) there is a greater availability of phosphocreatine, suggesting increased mitochondrial ATP synthesis. These results were unexpected as it has traditionally been thought that increased glucose metabolism would yield greater cardiac function in the failing heart. These data suggest targeting myocardial fat metabolism may provide novel treatments for cardiac dysfunction. Figure 1 Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Effect of a-tocopherol on the development of diabetic angiopathy, platelet aggregation, and prostacyclin-thromboxan system of rats with streptozotocin-induced diabetes

Under study were effects of intravenous infusions of a new emulsion, -tocopherol, on the development of diabetic microangiopathy, platelet -tocopherol level, ADP-induced platelet aggregation level, exogenic (from 14C-arachidonic acid) thromboxan (TxA2) biosynthesis in suspension of washed platelets and of prostacyclin (Pgb) one in isolated aortic rings of rats with streptozotocin-induced diabetes. Six-week injections of -tocopherol in a dose 100 mg/100 g b. w. with 48 h intervals immediately after development of streptozotocin-induced diabetes prevented the development of diabetic angiopathy but did not normalize platelet functional activity and Pgl2/TxA2 balance in vessels and platelets. Similar injections of -tocopherol in the presence of developed angiopathy resulted in its regressive development and normalization of the before-said prostanoid balance and platelet characteristics.

LIVING OFF THE FAT OF THE LAND: LIPID INFUSION FOR THE UNKOWN OVERDOSE

SESSION TITLE: Fellows Critical Care Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: October 18-21, 2020 INTRODUCTION: Lipid infusions are incorporated in the treatment of a variety of medication overdoses. We have found no study to date examining the use of lipids for unknown overdoses or ingestions that present lacking the signs and symptoms of a definitive toxidrome CASE PRESENTATION: A 30-year-old male with a history of drug abuse, ADHD, Crohn disease, and diverticulitis, presented to the ED from a drug and alcohol rehabilitation center with encephalopathy and incontinence. He admitted to taking a “Party Box” containing unknown hallucinogens and random pills. Urine drug screen was positive for benzodiazepine, cocaine, cannabinoid, opiate, and barbiturates. Labs showed a WBC of 16.7, chloride of 109, and bicarbonate of 21. He received IV fluids, lorazepam, and haloperidol before admission. On day 2 a rapid response was initiated for unresponsiveness. The patient had bradycardia, closed eyes, and involuntary lower extremity movement. EKG showed junctional bradycardia with rate of 38 bpm. A 1 Liter 20% IV lipid emulsion was administered over 2 hours. After 1 hour the bradycardia resolved. At 2 hours involuntary movements ceased. He was intubated for airway protection despite some improvement in mentation. By day 3 he was hemodynamically stable, awake, calm, and was extubated. DISCUSSION: For over 20 years, lipid infusions have been administered in animal models to reverse bupivacaine related cardiovascular collapse resulting in return of spontaneous circulation. Human case reports show efficacy treating lamotrigine, bupropion, calcium channel blocker, beta blocker, antipsychotic, tricyclic antidepressant, and local anesthesia systemic toxicity. Large scale human studies are absent. Although reported in the popular press for decades, parties where individuals trade various drugs—prescription or illicit—the incidence of this activity is unclear. Regulatory agencies and medical societies do not this behavior. PubMed searches for “pill party”, “fruit-salad party”, and “pharm party” returned no relevant results CONCLUSIONS: Our patient reported taking an unknown quantity of unspecified pills with subsequent cardiovascular and neurologic disturbances. Polypharmacy was manifest in our patient and drawing on the clinical signs and symptoms iabove, there was concern that this presentation could not be explained by drugs of abuse alone. To explain his bradycardia, we suspect that he may have ingested an AV nodal blocking agent. There is established benefit in using lipid infusions for specific overdoses. Data are inadequate in the routine use of lipids for unknown overdoses. The use of lipids for unknown overdoses that are associated with hemodynamic anomalies and neurological disorders merits further study, as it appears to carry a favorable risk-benefit potentia Reference #1: Weinberg GL. Lipid emulsion infusion: resuscitation for local anesthetic and other drug overdose. Anesthesiology. 2012;117(1):180–187 Reference #2: Lashari BH, Minalyan A, Khan W, Naglak M, Ward W. The Use of High-dose Insulin Infusion and Lipid Emulsion Therapy in Concurrent Beta-blocker and Calcium Channel Blocker Overdose. Cureus. 2018;10(11):e3534. Published 2018 Nov 1. doi:10.7759/cureus.3534 Reference #3: Hopkins LE, Sunkersing J, Jacques A. Too many pills to swallow: A case of a mixed overdose. J Intensive Care Soc. 2017;18(3):247–250. doi:10.1177/1751143717693860 DISCLOSURES: No relevant relationships by Firth Bowden, source=Web Response No relevant relationships by Edward Gray, source=Web Response No relevant relationships by Ali Nabavi, source=Web Response

Parenteral fish oil: An adjuvant pharmacotherapy for coronavirus disease 2019?

The new coronavirus associated with severe acute respiratory syndrome (SARS-CoV-2), surprisingly, does not affect only the lungs. The severe response to SARS-CoV-2 appears to include a “cytokine storm,” which indicates a state of hyperinflammation and subsequent dysfunction of multiple organs and tissues in the most severe cases. This could be the reason why populations at the highest risk for death from the SARS-CoV-2 infection–induced disease (coronavirus disease 2019 [COVID-19]) are those suffering from chronic low-grade inflammation, but prone to hyperinflammation. This includes individuals of advanced age and those with obesity, type 2 diabetes, hypertension, and metabolic syndrome. Inflammation resolution is strongly dependent on lipid mediators, the specialized pro-resolution mediators (SPMs). ω-3 polyunsaturated fatty acids (ω-3 PUFAs) are precursors of very potent SPMs, including resolvins, protectins, and maresins. Additionally, they are associated with a less aggressive inflammatory initiation, after competing with ω-6 fatty acids for eicosanoid synthesis. Therefore, it makes sense to consider the use of ω-3 PUFAs for clinical management of COVID-19 patients. ω-3 PUFAs may be given by oral, enteral, or parenteral routes; however, the parenteral route favors faster incorporation into plasma phospholipids, blood cells, and tissues. Here, we discuss these aspects to propose the parenteral infusion of ω-3 PUFAs as adjuvant immunopharmacotherapy for hospitalized patients with COVID-19.

972-P: Liraglutide Attenuates Lipid-Induced Microvascular Insulin Resistance in Humans

Insulin recruits skeletal and cardiac muscle microvasculature to increase insulin and nutrient delivery, but this action is lost in insulin resistant states. Glucagon-like peptide 1 (GLP-1) improves microvascular perfusion in humans with obesity and the GLP-1 receptor agonist liraglutide attenuates muscle microvascular insulin resistance (IR) in rodents. To examine whether GLP-1 receptor agonism improves insulin’s microvascular actions in humans with acute IR, 18 healthy human subjects randomly received a systemic infusion of either saline or lipid emulsion (20%, 45 mL x 1 h and then 30 mL x 4 h) for 5 h or lipid emulsion for 5 h + liraglutide pre-treatment (0.6, 1.2, then 1.8 mg daily SC each x 2 days) with euglycemic insulin clamp (1 mU/kg/min) superimposed for the last 120 min. Skeletal and cardiac muscle microvascular blood volume (MBV), flow-mediated dilation (FMD), pulse wave velocity (PWV), and augmentation index (AI) were determined before and after insulin clamp. Compared with saline admission, insulin failed to increase MBV following lipid infusion in both skeletal (28.4 ± 14.1% vs. -1.3 ± 9.6% respectively, p=0.011) and cardiac (28.4 ± 14.1% vs. -1.3 ± 8.9%, p=0.027) muscle, consistent with acute IR induced by lipid infusion in both microvascular beds. Liraglutide pre-treatment improved insulin-mediated increases in MBV in the presence of lipid infusion in skeletal (8.9 ± 13.5%, p=0.117 vs. saline) and cardiac (12.6 ± 12.1%, p=0.101 vs. saline) muscle. There was no significant change in PWV, AI, or FMD amongst admissions. Glucose infusion rates were not significantly different amongst admissions (saline 6.02 ± 0.52, lipid 5.58 ± 0.62, vs. liraglutide + lipid 5.46 ± 0.46 mg/kg/min). In conclusion, liraglutide pretreatment effectively ameliorates lipid-induced skeletal and cardiac muscle microvascular IR in healthy humans. These data provide a mechanistic insight into the metabolic and cardiovascular benefits of GLP-1 receptor agonism seen in humans with obesity and type 2 diabetes. Disclosure K. Love: None. L. Jahn: None. L. Hartline: None. Z. Liu: None. Funding American Diabetes Association (1-17-ICST-059 to Z.L.); National Institutes of Health (1R01DK102359-01A1)

166-OR: Lower Response of Connective Tissue Growth Factor (CTGF) to Exercise Characterizes Insulin Resistant Muscle

This study was undertaken to identify transcription factors that differentially respond to exercise in insulin resistance. Candidate transcription factors were identified from analysis of 5’-untranslated regions (5’-UTRs) of exercise responsive genes and from analysis of the 5’-UTRs of genes coding for proteins that differ in abundance in insulin resistance. Muscle biopsies were obtained from lean and obese subjects before, 30 min and 240 h. after a single exercise bout. Insulin sensitivity was assessed through glucose clamps. Obese subjects (n=8) were insulin resistant compared to lean (n=12) (7.0 ± 0.95 vs. 11.3 ± 0.8 mg∙kg FFM-1∙min-1, P<0.05) but performed exercise at the same intensity (VO2peak 35.0 ± 1.9 vs. 35.2 ± 3.9 ml∙min-1∙kg FFM-1, NS). Statistical over-representation analyses showed that proteins differing in abundance between healthy and insulin resistant resting muscle included those involved in mitochondrial function, protein targeting and translation, and metabolism. Transcription factor enrichment analysis of genes coding for these proteins revealed new candidate transcription factors. Q-rt-PCR analysis from pre and post-exercise muscle biopsies revealed several transcription and growth factors had altered responses to exercise in insulin resistant subjects, including EGR3, RELA, ATF2 and SP1. We previously showed that higher CTGF abundance and expression were associated with insulin resistance induced by a lipid emulsion infusion, along with extracellular matrix reorganization and tissue remodeling. Here, CTGF mRNA responded briskly 30 min after exercise in insulin sensitive but not insulin resistant subjects (4.7 ± 1.0 vs. 1.0 ± 0.22), returning to near-basal levels in both groups after 24 h. The lower response of CTGF expression to exercise in insulin resistance suggests that it may mediate the capacity of muscle to remodel itself following exercise, and partially explain the exercise resistance associated with insulin resistance. Disclosure R. Zapata Bustos: None. P.R. Langlais: None. D.K. Coletta: None. E.A. De Filippis: None. D. Grandjean: None. L. Mandarino: None. Funding National Institutes of Health (R01DK047936, DK066483, R01DK094013)

Lamotrigine Toxicosis Treated with Intravenous Lipid Emulsion Therapy in a Dog

A female spayed dachshund/mixed-breed dog was evaluated following ingestion of lamotrigine tablets with subsequent rapid onset of vomiting, diarrhea, and generalized tremoring. On initial examination, the dog was moderately obtunded and nonambulatory with intermittent myoclonus and hyperesthesia. Electrocardiogram revealed sinus tachycardia with prolongation of the QT interval. Intravenous lipid emulsion (ILE) infusion was initiated, with reduction in tremoring and improved patient mentation being noted after ∼20 min of therapy. An elevated cardiac troponin I value measured at 1.02 ng/mL the day after presentation. Serum toxicological assay revealed marked reduction in serum lamotrigine levels following ILE and continued reduction during hospitalization. The dog's clinical signs resolved, corrected QT interval returned to normal, and the patient was discharged 38 hr after presentation. Individual cases of lamotrigine toxicosis have not been fully reported in veterinary literature. This case report documents the rapid onset of clinical signs including neurologic dysfunction, cardiac arrhythmias, and transient corrected QT prolongation. Serial serum concentrations of lamotrigine showed a rapid reduction with ILE therapy and corresponded with clinical recovery, suggesting efficacy of ILE treatment in this case.

Treatment of Bupropion Toxicity with Lipid Emulsion

We have read with interest the case report, “Successful Management of Adolescent Bupropion Overdose with Intravenous Lipid Emulsion Therapy,” recently published in the Journal of Pediatric Intensive Care.[1] Lipid emulsion is effective in the treatment of acute toxicity induced by local anesthetics or nonlocal anesthetic drugs, including amitriptyline, bupropion, and verapamil, in pediatric patients.[2] A previous in vitro study reported that the magnitude of the reduction of the serum concentration of bupropion, which is a highly lipid-soluble antidepressant (log [octanol/water partition coefficient]: 3.2), was 46 by 2% lipid emulsion (Intralipid).[3] In addition, the magnitude of the sequestration of drugs with varied lipid solubility by lipid emulsion is dependent mainly on the lipid partition coefficient and partially on the volume of distribution, which appears to account for 88% of variations in the reduction of drug serum concentration by lipid emulsion.[3] As suggested by Bornstein et al, the lipid sink theory, which is considered the mechanism underlying the effect of lipid emulsion as a nonspecific antidote, states that lipid emulsion absorbs highly lipid-soluble drugs, such as bupivacaine (log [octanol/water partition coefficient]: 3.41), from the heart.[1] [4] However, the following comments should be considered to understand this case report well. First, the first administration of lipid emulsion improved the mental status of the patient.[1] On day 3, the second administration of lipid emulsion was performed due to the recurrence of an altered mental status.[1] The elimination half-life of bupropion is 29 ± 9 hours.[5] In addition, the absorption of a toxic dose following oral administration (enteral route) is more prolonged than that following intravenous administration, leading to extended toxicity.[6] In contrast, Intralipid has a very short half-life (13.7 ± 5.2 minutes).[7] Considering previous reports, the lipid phase of lipid emulsion appears to absorb highly lipid-soluble bupropion from the heart and brain for a very short period following lipid emulsion administration.[3] [7] Furthermore, 1% of plasma triglyceride concentration, which provides lipemic plasma without fat overload, is sufficient to exert scavenging and cardiotonic effects on the toxicity induced by an enteral overdose.[6] Thus, the altered mental status on day 3 following a marked improvement after the first administration of lipid emulsion may be ascribed to a greatly reduced concentration of Intralipid.[1] A previous report recommends the following lipid emulsion regimen to treat toxicity induced by enteral overdose: bolus administration of Intralipid 1.5 mL/kg for 1 minute and subsequently 0.25 mL/kg/min for an additional 3 minutes, followed by intravenous infusion of 0.025 mL/kg/min (up to 6.5 hours) to theoretically maintain a 1% plasma triglyceride concentration.[6] This regimen, as an adjuvant, can be used with supportive care in cases of toxicity induced by oral overdose.[6] However, further research in an in vivo model on the optimal dosing regimen of lipid emulsion for the treatment of toxicity following oral overdose of bupropion is needed because the pharmacokinetics of an oral overdose are different from those of intravenous overdose (e.g., local anesthetic systemic toxicity). Second, initially, lipid sink was widely accepted as the underlying mechanism of lipid emulsion treatment.[4] However, a previous study using a physiologically based pharmacokinetic model reported that lipid emulsion decreased only 11 and 18% bupivacaine concentrations in the heart and brain, respectively.[8] The free bupivacaine concentration was not significantly different between the control and lipid emulsion groups in an in vivo study after administration of a nontoxic dose of bupivacaine in humans.[9] Thus, lipid shuttle has recently been widely accepted as the mechanism of lipid emulsion treatment; it states that lipid emulsion absorbs lipid-soluble drugs, such as bupivacaine, from the heart and then the lipid emulsion, containing the sequestered lipid-soluble drug (e.g., bupivacaine), is transported to the liver and muscle for detoxification and storage, leading to enhanced redistribution.[4] We believe that this case report contributes valuable data on the efficacy of lipid emulsion treatment in bupropion toxicity and emphasizes the need for continuous infusion of lipid emulsion following the initial bolus administration in lipid emulsion treatment.

Doxorubicin concentration in brain remains high for one day after triolein emulsion infusion induced BBB opening

Aim: The purpose of this study was to assess changes in doxorubicin concentration in rabbit brain with respect to time after BBB opening induced by triolein emulsion infusion via a carotid artery and the mechanism of BBB opening.Materials and Methods: Doxorubicin (2.4 mg/kg) was infused immediately after triolein emulsion (1%) into rabbit carotid arteries. Bilateral hemispheres were harvested 2, 4, 6 12 and 24 h later and doxorubicin concentrations were measured fluorometrically. Doxorubicin concentration ratios of ipsilateral versus contralateral hemispheres were calculated, and a TEM study was performed to investigate the mechanism responsible for the increased vascular permeability induced by triolein.Results: Doxorubicin concentrations were higher in ipsilateral hemispheres at all time points, and peaked at 2 h after treatment. Doxorubicin was still detected in ipsilateral hemispheres at 24 h after treatment. TEM showed tight junction opening by triolein emulsion with lanthanum tracer spillage into neural interstitium and transcytotic vesicles.Conclusion: Doxorubicin was delivered into neural interstitium because of the increased vascular permeability of the BBB induced by triolein emulsion. Doxorubicin concentrations in brain peaked within 2 h of triolein and doxorubicin administration and remained high for 24 h. The study shows increased vascular permeability induced by triolein emulsion may involve paracellular and transcellular pathways.

Effect of short-term administration of lipid emulsion on endothelial glycocalyx integrity in ICU patients - A microvascular and biochemical pilot study.

Endothelial glycocalyx (EG) is a carbohydrate-rich vascular lining of the apical surface of endothelial cells. It has been proved to have an essential role in vascular homeostasis. Lipid emulsions as part of parenteral nutrition (PN) are widely used in patients in the setting of critical care and perioperative medicine. Due to their structure, lipids may potentially interact with EG. The aim of the study was to evaluate the effect of lipid emulsion on EG. To assess the influence of lipid emulsion on EG integrity in ICU patients using a videomicroscopic and biochemical methods. Patients in surgical ICU after major abdominal surgery or cardio surgery and in general ICU were assessed for eligibility for this pilot observational study in University Hospital. The study was performed during the first day of adding lipids as a part of their PN. The patients were given the SMOFlipid 20% for 6 hours in prescribed dose of approx. 1 g/kg of body weight. EG integrity was measured indirectly by automated sublingual videomicroscopy calculating a parameter PBR which describes the amount of lateral deviation of red blood cells from the central column and by levels of syndecan-1 and syndecan-4 in plasma as EG degradational products. Measurements were performed before lipid administration (T0) and 30 minutes after (T6) the infusion of lipid emulsion was completed. The statistical analysis was performed at the level of significance p < 0.05, data are expressed as mean ± standard deviation (SD) and for PBR as median and interquartile range (IQR). Fifteen patients were studied, from them 9 included in final analysis. PBR (expressed in μm) increased after the lipid infusion with no statistical significance (T0 = 2.10; 1.97-2.33 vs. 2.28; 2.11-2.45, p = 0.13). At T6 both syndecans showed statistically significant decrease in their particular levels. Syndecan-1 at T0 = 2580±1013 ng/l, resp. at T6 = 2365±1077 ng/l, p = 0.02; syndecan-4 at T0 = 134±29 ng/l, resp. at T6 = 123±43 ng/l, p = 0.04. In our study, we showed that six hours long SMOFlipid 20% infusion had no detrimental effect on the EG integrity as assessed by PBR value and by syndecan-1 and syndecan-4 plasmatic levels. Observed decrease of syndecans shortly after lipid infusion allows us to hypothesize even possibly protecting effect of lipids on EG.

Resuscitation Following a Bupivacaine Injection for a Cervical Paravertebral Block.

BackgroundCardiac arrest related to nerve blockade using a local anaesthetic is a rare event. We report a case of bupivacaine severe cardiovascular toxicity following cervical paravertebral nerve block.Case presentationA 44-year-old female was admitted to Republican Vilnius University Hospital, with symptoms of sustained severe pain in her neck that radiated to both arms. Multiple cervical intervertebral hernias with spinal stenosis were confirmed by magnetic resonance imaging. Following infiltration of the subcutaneous tissue with a 0.5 % bupivacaine solution, an 18-gauge spinal needle was used to perform the paravertebral block at the C6 level. Bupivacaine was injected in incremental doses to a total of 10 mL. Rapid loss of consciousness and cardiovascular collapse suggested a neuraxial injection of bupivacaine. Long-lasting cardiopulmonary resuscitation, including chest compressions, defibrillation attempts for refractory ventricular fibrillation, medications, mechanical ventilation, and intravenous lipid emulsion infusion, was successful. No severe adverse outcomes other than acute kidney injury and chest pain related to prolonged chest compressions were documented.ConclusionsThis case report emphasizes the necessity of ensuring adequate safety precautions to avoid local anaesthetic systemic toxicity. Lipid emulsion preparations should be available in all hospital settings where local anaesthetics are used for regional anaesthesia or pain management.

A Rat Model of Human Lipid Emulsion Digestion.

A better understanding of how dietary lipids are processed by the human body is necessary to allow for the control of satiation and energy intake by tailored lipid systems. To examine whether rats are a valid model of human dietary lipid processing and therefore useful for further mechanistic studies in this context, we tested in rats three lipid emulsions of different stability, which alter satiety responses in humans. Different sets of 15 adult male Sprague Dawley rats, equipped with gastric catheters alone or combined with hepatic portal vein (HPV) and vena cava (VC) catheters were maintained on a medium-fat diet and adapted to an 8 h deprivation/16 h feeding schedule. Experiments were performed in a randomized cross-over study design. After gastric infusion of the lipid emulsions, we assessed gastric emptying by the paracetamol absorption test and recorded in separate experiments food intake and plasma levels of gastrointestinal hormones and metabolites in the HPV. For an acid stable emulsion, slower gastric emptying and an enhanced release of satiating gastrointestinal (GI) hormones were observed and were associated with lower short-term energy intake in rats and less hunger in humans, respectively. The magnitude of hormonal responses was related to the acid stability and redispersibility of the emulsions and thus seems to depend on the availability of lipids for digestion. Plasma metabolite levels were unaffected by the emulsion induced changes in lipolysis. The results support that structured lipid systems are digested similarly in rats and humans. Thus unstable emulsions undergo the same intragastric destabilization in both species, i.e., increased droplet size and creaming. This work establishes the rat as a viable animal model for in vivo studies on the control of satiation and energy intake by tailored lipid systems.

SUN-PO002: Dynamics of Polyunsturated Fatty Acid Profile in Plasma, Liver and Blood Leukocytes After Ending Parenteral Infusion of Fish Oil Lipid Emulsion

SUN-PO002: Dynamics of Polyunsturated Fatty Acid Profile in Plasma, Liver and Blood Leukocytes After Ending Parenteral Infusion of Fish Oil Lipid Emulsion

SUN-PO003: Dynamics of Polyunsaturated Fatty Acid Uptake in Plasma, Liver and Blood Leukocytes After Parenteral Infusion of Fish Oil Lipid Emulsion

SUN-PO003: Dynamics of Polyunsaturated Fatty Acid Uptake in Plasma, Liver and Blood Leukocytes After Parenteral Infusion of Fish Oil Lipid Emulsion

Effects of abomasal infusions of fatty acids and one-carbon donors on hepatic ceramide and phosphatidylcholine in lactating Holstein dairy cows

Our objectives were to (1) determine whether the abomasal infusion of behenic acid (C22:0) elevated hepatic ceramide relative to palmitic acid (C16:0) or docosahexaenoic acid (C22:6n-3) infusion; (2) assess whether the abomasal infusion of choline chloride or l-serine elevated hepatic phosphatidylcholine (PC) in cows abomasally infused with C16:0; and (3) characterize the PC lipidome in cows abomasally infused with C22:6n-3, relative to C16:0 or C22:0 infusion. In a 5 × 5 Latin square design, 5 rumen-cannulated Holstein cows (214 ± 4.9 DIM; 3.2 ± 1.1 parity) were enrolled in a study with 6-d periods. Abomasal infusates consisted of (1) palmitic acid (PA; 98% C16:0); (2) PA + choline chloride (PA+C; 50 g/d choline chloride); (3) PA + l-serine (PA+S; 170 g/d l-serine); (4) behenic acid (BA; 92% C22:0); and (5) an algal oil rich in docosahexaenoic acid (DHA; 44% C22:6n-3). Emulsion infusates provided 301 g/d of total fatty acids containing a minimum of 40 g/d of C16:0. Cows were fed a corn silage-based diet. Milk was collected on d -2, -1, 5, and 6. Blood was collected and liver biopsied on d 6 of each period. Although we did not detect differences in milk yield, milk fat yield and content were lower in cows infused with DHA relative to PA. Plasma triacylglycerol concentrations were lower with DHA treatment relative to PA or BA. Cows infused with DHA had lower plasma insulin concentrations relative to cows infused with PA only. For objective 1, hepatic ceramide-d18:2/22:0 was highest in cows infused with BA relative to other treatments. For objective 2, plasma free choline concentrations were greater in PA+C cows relative to PA; however, we did not observe this effect with PA+S. Plasma total PC concentrations were similar for all treatments. Regarding the hepatic lipidome, a total of 18 hepatic PC were higher (e.g., PC-16:1/18:2) and 25 PC were lower (e.g., PC-16:0/22:6) with PA+C infusion relative to PA. In addition, 17 PC were higher (e.g., PC-20:3/22:5) and 21 PC were lower (e.g., PC-18:0/22:6) with PA+S infusion relative to PA. For objective 3, hepatic concentrations of many individual saturated PC (e.g., PC-18:0/15:0) were lower with DHA relative to other treatments. Hepatic concentrations of highly unsaturated PC with very-long-chain fatty acids (e.g., PC-14:0/22:6) were higher in DHA-infused cows relative to PA, PA+C, PA+S, or BA. The abomasal infusion of emulsions containing palmitic acid, palmitic acid with choline chloride or serine, behenic acid, or docosahexaenoic acid influence the hepatic ceramide and PC profiles of lactating cows.

1849-P: Importance of Insulin’s Direct and Indirect Effects on Postprandial Hepatic Glucose Uptake

In heathy individuals the liver is a primary site of glucose disposal, it is in a state of glucose uptake most of the day, and this process is impaired in diabetes. Insulin stimulates hepatic glucose uptake (HGU) but the importance of its indirect effects (at fat, brain and pancreatic alpha cells) in driving HGU is unclear. Thus, the aim of this study was to determine the impact of insulin’s indirect mechanisms of control of HGU. Postprandial conditions were simulated for 4-hour in conscious dogs (n=7/group) by infusing somatostatin, intraportal insulin (1.8 mU/kg/min) and glucose (4 mg/kg/min), and leg vein glucose (to clamp arterial glucose at 2-fold basal). In one group insulin’s direct and indirect effects on the liver were both present (D+I) while in the other insulin’s indirect effects were blocked (D-only). In D+I the basal intraportal glucagon infusion rate was decreased to create a progressive decline in glucagon over time, FFA levels were allowed to fall, and brain insulin action was allowed to increase. In D-only glucagon and FFA levels were maintained at basal levels by infusions of intraportal glucagon and leg vein lipid emulsion. Hypothalamic insulin action was blocked by 3rd ventricle infusion of an insulin receptor antagonist. In the D+I and D-only groups, respectively, hepatic insulin increased during the experimental period (from 20±3 to 88±8 and 21±3 to 89±8 µU/ml), hepatic glucagon fell or remained basal (39±5 to 24±3 and 40±6 to 41±2 pg/ml) and arterial FFA fell or remained basal (1069±19 to 99±23 and 1195±63 to 998±99 µmol/l). HGU and net hepatic glucose uptake (NHGU) were independently measured using tracer and cold glucose balance techniques. The AUCs for HGU and NHGU (mg/kg/240 min) in D+I were 841±143 and 792±105, respectively, and 738±130 and 698±58 in D-only (P=0.6 and 0.4 between groups, respectively). Thus, in the healthy animal, HGU responds normally to insulin even in the absence of the hormone’s indirect effects. Instead HGU is driven almost exclusively by insulin’s direct effects. Disclosure D.S. Edgerton: Speaker's Bureau; Self; Novo Nordisk A/S. G. Kraft: Consultant; Self; Metavention. B. Farmer: None. M.S. Smith: None. P.E. Williams: None. A.D. Cherrington: Board Member; Self; Biocon, Fractyl Laboratories, Inc., Metavention, Sensulin, LLC., vTv Therapeutics, Zafgen, Inc. Consultant; Self; Abvance, Boston Scientific Corporation, California Institute for Biomedical Research, Galvani Bioelectronics Limited, MedImmune, Novo Nordisk Inc., Thetis Pharmaceuticals LLC. Research Support; Self; Abvance, Diasome Pharmaceuticals, Inc., Novo Nordisk Inc. Stock/Shareholder; Self; Abvance, Biocon, Fractyl Laboratories, Inc., Metavention, Novo Nordisk Inc., Sensulin, LLC., Thetis Pharmaceuticals LLC, Zafgen, Inc. Funding National Institutes of Health

Liquid Chromatography Analysis of Clozapine in Rat Brain Tissue, Using its Molecularly Imprinted Polymer after Administration of Toxic Dose of Drug and Lipid Emulsion Therapy

Background:Molecularly imprinted polymers (MIPs) are synthetic polymers that have a selective site for a given analyte, or a group of structurally related compounds, that make them ideal polymers to be used in separation processes.Objective:An optimized molecularly imprinted polymer was selected and applied for selective extraction and analysis of clozapine in rat brain tissue.Methods:A molecularly imprinted solid-phase extraction (MISPE) method was developed for preconcentration and cleanup of clozapine in rat brain samples before HPLC-UV analysis. The extraction and analytical process was calibrated in the range of 0.025-100 ppm. Clozapine recovery in this MISPE process was calculated between 99.40 and 102.96%. The limit of detection (LOD) and the limit of quantification (LOQ) of the assay were 0.003 and 0.025 ppm, respectively. Intra-day precision values for clozapine concentrations of 0.125 and 0.025 ppm were 5.30 and 3.55%, whereas inter-day precision values of these concentrations were 9.23 and 6.15%, respectively. In this study, the effect of lipid emulsion infusion in reducing the brain concentration of drug was also evaluated.Results:The data indicated that calibrated method was successfully applied for the analysis of clozapine in the real rat brain samples after administration of a toxic dose to animal. Finally, the efficacy of lipid emulsion therapy in reducing the brain tissue concentration of clozapine after toxic administration of drug was determined.Conclusion:The proposed MISPE method could be applied in the extraction and preconcentration before HPLC-UV analysis of clozapine in rat brain tissue.

Intravenous Triacylglycerol Infusion Promotes Ceramide Accumulation and Hepatic Steatosis in Dairy Cows

Increased plasma free fatty acids (FFAs) impair insulin sensitivity in dairy cows via unknown mechanisms. In nonruminants, saturated FFAs upregulate the hepatic synthesis and secretion of ceramide, which inhibits insulin action. We aimed to determine whether an increase in plasma FFAs promotes hepatic and plasma ceramide accumulation in dairy cows. Six nonpregnant, nonlactating Holstein cows were used in a study with a crossover design and treatments consisting of intravenous infusion of either saline (control) or triacylglycerol emulsion (TG; 20 g/h) for 16 h. The feeding level was set at 120% of energy requirements. Blood was collected at regular intervals and liver was biopsied at 16 h. Ceramides, monohexosylceramides (Glc/Gal-Cer), lactosylceramides (LacCer), and sphingomyelins (SMs) in plasma and liver were profiled. Hepatic expression of ceramide synthases was determined. Data were analyzed with the use of mixed models, regressions, and Spearman rank correlations. After 16 h of infusion, plasma FFA concentrations were >5-fold and liver triacylglycerol concentrations were 4-fold greater in TG cows, relative to control. Plasma total and very long-chain ceramide (e.g., C24:0-ceramide) concentrations increased ∼4-fold in TG over control by hour 16 of infusion, while C16:0-ceramide were not modified by TG. Infusion of TG increased plasma Glc/Gal-Cer (e.g., C16:0-Glc/Gal-Cer, 4-fold by hour 16) relative to control, but did not alter LacCer or SM concentrations. Hepatic ceramide concentrations increased with TG relative to control (e.g., C24:0-ceramide by 1.7-fold). Hepatic expression of ceramide synthase 2 was 60% greater after TG infusion compared with the control. Circulating ceramides were related to circulating FFA and hepatic triacylglycerol concentrations (e.g., C24:0-ceramide, ρ=0.73 and 0.80, respectively; P<0.001). Hepatic ceramide synthesis is associated with elevations in circulating FFAs and hepatic triacylglycerol during the induction of hyperlipidemia in dairy cows. This work supports the emerging evidence for the role of ceramide during hepatic steatosis and insulin antagonism in cows.

Low-dose intravenous lipid emulsion as a safe treatment for lipophilic intoxications in five cats

The use of a low-dose infusion of intravenous lipid emulsion (ILE) in five young cats presented with acute neurotoxicity is reported. Suspected toxic compounds were permethrin (three, dermal), fipronil/eprinomectin/praziquantel (one,...