Emulsiones lipídicas en la intoxicación por anestésicos locales y otros fármacos. Revisión sobre mecanismos de acción y recomendaciones de uso / Lipid emulsions in the treatment of intoxications by local anesthesics and other drugs. Review of mechanisms of action and recommendations for use

La emulsiones lipídicas intravenosas (ELI) se han utilizado ampliamente para el tratamiento de la intoxicación por anestésicos locales (AL) y se han propuesto como tratamiento de la intoxicación por otros fármacos. Sin embargo, el grado de evidencia de este tipo de terapias no es sólido, ya que proviene en su mayoría de casos clínicos. El objetivo de esta revisión narrativa es describir los mecanismos de acción propuestos para las ELI en la intoxicación por AL y otros fármacos, y evaluar los estudios recientes realizados en animales que sustentan las recomendaciones de su uso y la experiencia en humanos que apoyan el empleo de las ELI tanto en la intoxicación por AL como por otros fármacos. Para ello, se llevó a cabo una búsqueda en las bases de datos Embase, Medline, Cochrane y Google Scholar abarcando los artículos relevantes durante los últimos 10 años. En caso de intoxicación por AL, se recomienda aplicar los protocolos dictados por las guías internacionales, sabiendo que el grado de evidencia no es muy elevado. En la intoxicación por otros fármacos, las ELI están aconsejadas en situaciones graves inducidas por xenobióticos liposolubles que no responden al tratamiento estándar.(AU)

Intravenous lipid emulsions (ILEs) have been used widely for the treatment of local anesthetic (LA) poisoning and have been proposed as a treatment for intoxication by other drugs. However, the degree of evidence for this kind of therapy is not strong, as it comes mostly from clinical cases. The aim of this narrative review is to describe the proposed mechanisms of action for ILEs in poisoning by LA and other drugs and to evaluate recent studies in animals that support the recommendations for their use and the experience in humans that support the use of ILESs in both LA and other drug poisoning. For this purpose, a search was performed in the Embase, Medline and Google Scholar databases covering relevant articles over the last 10 years. In the case of AL poisoning, we recommend applying the protocols dictated by international guidelines, knowing that the degree of evidence is not very high. In poisoning by other drugs, ILEs are recommended in serious situations induced by liposoluble xenobiotics that do not respond to standard treatment.(AU)

Blood clearance kinetics and organ delivery of medium-chain triglyceride and fish oil-containing lipid emulsions: Comparing different animal species.

BACKGROUND & AIMS: Medium-chain triglycerides (TG) (MCT) and fish oil (FO) TG are incorporated as the core TG component into intravenous (IV) lipid emulsions for infusion in parenteral nutrition. Bolus injections of IV emulsions, on the other hand, have emerged as a novel therapeutic approach to treat various acute disorders. However, intravascular metabolism and organ delivery of acute IV injection of emulsions containing both MCT and FO are not fully defined, nor have they been characterized across common experimental animal models. We characterized and compared blood clearance kinetics and organ distribution of bolus injections of MCT/FO emulsions among different animal species. We also examined whether sex differences or feeding status can affect catabolic properties of MCT/FO lipid emulsions. DESIGN: Blood clearance rates of lipid emulsions with specific TG composition were compared in rats IV injected with [3H]cholesteryl hexadecyl ether labeled pure n-6 long-chain (LCT) and n-3 FO TG lipid emulsions, or emulsions containing MCT and FO at different ratios (wt/wt), which include 8:2 (80% MCT: 20% FO), 5:4:1 (50% MCT: 40% LCT: 10% FO) and SMOF (30% LCT: 30% MCT: 25% olive oil: 10% FO). Dose-response effects (0.016 mg-1.6 mg TG/g body weight) of the MCT/FO 8:2 emulsions on blood clearance properties and organ delivery were determined in both mice and rats. Blood clearance kinetics and organ uptake of MCT/FO 8:2 emulsions were compared between male and female rats and between fed and fasted rats. Changes in plasma lipid profiles after acute injections of MCT/FO 8:2 lipid emulsion at different doses (0.043, 0.133, and 0.4 mg TG/g body weight) were characterized in non-human primates (Cynomolgus monkeys). RESULTS: MCT/FO 8:2 emulsion was cleared faster in rats when compared with other emulsions with different TG contents. Mice had faster blood clearance and higher fractional catabolic rates (FCR) when compared with the rats injected with MCT/FO 8:2 emulsions regardless of the injected doses. Mice and rats had similar plasma TG and free fatty acid (FFA) levels after low- or high-dose injections of the MCT/FO emulsion. Tissue distribution of the MCT/FO 8:2 lipid emulsion are comparable between mice and rats, where liver had the highest uptake per recovered dose among all organs (>60%). Feeding status and sex differences did not alter the blood clearance rate of the MCT/FO 8:2 emulsion in rats. In a nonhuman primate model, dose-response increases in plasma TG and FFA were observed after IV injection of MCT/FO 8:2 emulsions within the 1st 10 min. CONCLUSION: A lipid emulsion containing both MCT and FO TG is cleared rapidly in blood and readily available for organ uptake in rodent and primate animal models. Characterization of the blood clearance properties of the MCT/FO 8:2 emulsion administered in various animal models may provide further insight into the safety and efficacy profiles for future therapeutic use of bolus injections of MCT/FO emulsions in humans.

Follistatin-like 1 as a Novel Adipomyokine Related to Insulin Resistance and Physical Activity.

BACKGROUND AND AIMS: Follistatin-like protein-1 (FSTL-1) is considered to be an adipokine or myokine that could be a potential regulator of metabolism. Our purpose is to investigate the relationship between circulating FSTL-1 levels and insulin resistance (IR) in type 2 diabetes mellitus (T2DM) and to identify the regulatory factors. METHODS: FSTL-1 expression in C57BL/6J and db/db mice was examined by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and Western blots. Serum FSTL-1 levels were measured by enzyme-linked immunosorbent assay in 298 T2DM patients and 202 healthy controls. Changes in the circulating FSTL-1 level were observed during the oral glucose tolerance test, EHC (euglycemic-hyperinsulinemic clamp), lipid infusion, acute exercise, and cold-exposure test. RESULTS: We found that FSTL-1 protein expression in the adipose tissue of db/db mice was significantly higher than that of wild-type mice. Importantly, circulating FSTL-1 levels in T2DM and overweight/obese participants were higher than those in healthy and lean individuals, and was related to HOMA-IR, adiponectin, and obesity- and metabolism-related parameters. In the intervention study, 45 minutes of physical activity was found to significantly increase the circulating FSTL-1 concentration in young, healthy participants. Further, FSTL-1 protein expression in adipose tissue rose dramatically in response to physical activity in mice. Hyperinsulinemia during EHC and acute elevated FFA induced by lipid infusion resulted in a significant decrease in the circulating FSTL-1 levels. However, no change was found in the circulating FSTL-1 levels in response to the oral glucose challenge or cold-exposure test. CONCLUSIONS: FSTL-1 may be an adipomyokine associated with insulin resistance and physical activity, and circulating FSTL-1 levels are increased in patients with T2DM.

Half-life of plasma phytosterols in very low birth weight preterm infants on routine parenteral nutrition with vegetable oil-based lipid emulsions.

BACKGROUND: Phytosterols in vegetable oil (VO)-based lipid emulsions (LE) likely contribute to parenteral nutrition-associated cholestasis (PNAC) in preterm infants. No characterization of plasma phytosterol half-lives has been done in very low birth weight (VLBW) preterm infants receiving parenteral nutrition (PN) with LE. METHODS: In a prospective cohort study, 45 VLBW preterm infants who received PN underwent serial blood sample measurements of sitosterol (SITO), campesterol (CAMP), and stigmasterol (STIGM). Plasma phytosterol half-lives were calculated from the phytosterol concentrations-decay curves by using a single-compartment model. RESULTS: After the stop of the intravenous LE, study infants had significantly lower plasma total CAMP, STIGM and SITO concentrations. The decay of plasma phytosterol concentrations was monoexponential. Half-life of plasma total CAMP, STIGM and SITO was 13.5 ± 6.9, 10.3 ± 4.5 and 10.3 ± 4.0 days, respectively. Plasma phytosterol half-lives did not correlate with gestational age, birth weight, cumulative phytosterol intakes and plasma conjugated bilirubin. CONCLUSION: VLBW preterm infants on PN with LE had rather long plasma phytosterol half-lives similar to hypercholesterolemic adults and phytosterolemic homozygotes patients. We speculate that the accumulation of phytosterols could contribute to their vulnerability to PNAC. CLINICAL TRIAL REGISTRY: The Ethics Committee of Marche-Italy (DG/469); www.clinicaltrials.gov (identification number NCT02758834).

Lipid emulsion in local anesthetic toxicity.

PURPOSE OF REVIEW: Enthusiasm for regional anesthesia has been driven by multimodal benefits to patient outcomes. Despite widespread awareness and improved techniques (including the increasing use of ultrasound guidance for block placement), intravascular sequestration and the attendant risk of local anesthetic systemic toxicity (LAST) remains. Intravenous lipid emulsion (ILE) for the treatment of LAST has been endorsed by anesthetic regulatory societies on the basis of animal study and human case report data. The accumulated mass of reporting now permits objective interrogation of published literature. RECENT FINDINGS: Although incompletely elucidated the mechanism of action for ILE in LAST seemingly involves beneficial effects on initial drug distribution (i.e., pharmacokinetic effects) and positive cardiotonic and vasoactive effects (i.e., pharmacokinetic effects) acting in concert. Recent systematic review by collaborating international toxicologic societies have provided reserved endorsement for ILE in bupivacaine-induced toxicity, weak support for ILE use in toxicity from other local anesthetics, and largely neutral recommendation for all other drug poisonings. Work since publication of these recommendations has concluded that there is a positive effect on survival for ILE when animal models of LAST are meta-analyzed and evidence of a positive pharmacokinetic effect for lipid in human models of LAST. SUMMARY: Lipid emulsion remains first-line therapy (in conjunction with standard resuscitative measures) in LAST. Increasing conjecture as to the clinical efficacy of ILE in LAST, however, calls for high-quality human data to refine clinical recommendations.

Formulation, Optimization, Characterization, and Pharmacokinetics of Progesterone Intravenous Lipid Emulsion for Traumatic Brain Injury Therapy.

Traumatic brain injury (TBI) is a major cause of mortality and disability throughout the world. Progesterone (PROG) plays an important role in neurologic treatment. The aim of this study was to develop a progesterone formulation with good physical and chemical stability. Progesterone intravenous lipid emulsion (PILE) was prepared based on one-factor-at-a-time experiments and orthogonal design. The optimal PILE was evaluated for mean particle size, particle size distribution, zeta potential, morphology, pH, osmolarity, entrapment efficiency, storage stability, and pharmacokinetics in ICR mice compared with the commercial progesterone products. The droplets of PILE had the smallest possible diameters of 218.0 ± 1.8 nm and adequate zeta potential of -41.1 ± 0.9 mV. The volume percentage of droplets exceeding 5 µm (PFAT5) of PILE was 0.003 ± 0.0015% and much less than the specified standard. The TEM imaging proved that emulsion droplets had a smooth spherical appearance. Chemically and physically stable PILE was obtained with excellent entrapment efficiency that was up to 95.23%, with suitable pH at 7.15 ± 0.01 and osmolarity at 301.3 ± 1.2 mOsmol/l. Storage stability tests indicated that the emulsion was stable long term under ambient temperature conditions. Animal studies demonstrated that the emulsion was more effective with the higher progesterone concentration in the brain compared with commercial products. Therefore, the optimized PILE would offer great promise as a means of progesterone delivery for TBI therapy.

The Effect of Lipid Emulsion on Pharmacokinetics of Bupivacaine in Rats: Long-Chain Triglyceride Versus Long- and Medium-Chain Triglyceride.

BACKGROUND: Lipid infusions have been proposed to treat local anesthetic-induced cardiac toxicity. This study compared the effects of long-chain triglyceride (LCT) emulsions with those of long- and medium-chain triglyceride (LCT/MCT) emulsions on the pharmacokinetics of bupivacaine in a rat model. METHODS: After administration of intravenous infusion of bupivacaine at 2 mg·kg·min for 5 minutes in Sprague-Dawley (SD) rats, either Intralipid 20%, an LCT emulsion (LCT group, n = 6), or Lipovenoes 20%, an LCT/MCT emulsion (LCT/MCT group, n = 6), was infused at 2mg·kg·min for 5 minutes. The concentrations of total plasma bupivacaine and bupivacaine that were not bound by lipid (lipid unbound) were measured by a liquid chromatography-tandem mass spectrometric method. A 2-compartmental analysis was performed to calculate the lipid-bound percentage of bupivacaine and its pharmacokinetics. RESULTS: In the LCT group, the clearance (15 ± 2 vs 10 ± 1 mL·min·kg, P = .003) was higher; the volume of distribution (0.57 ± 0.10 vs 0.36 ± 0.11 L·kg, P = .007) and K21 (0.0100 ± 0.0018 vs 0.0070 ± 0.0020 min, P = .021, P' = .032) were larger; and the area under the blood concentration-time curve 0 - t; (605 ± 82 vs 867 ± 110 mgL·min, P =.001) and the area under the blood concentration-time curve (0 - ∞) (697 ± 111 vs 991 ± 121 mgL·min, P =.001) were less, when compared with the LCT/MCT group. CONCLUSIONS: LCT emulsions are more effective than LCT/MCT emulsions in the metabolism of bupivacaine through demonstration of a superior pharmacokinetic profile.

Vitamin K1 distribution following intravenous vitamin K1-fat emulsion administration in rats.

This study investigated vitamin K1 (VK1 ) distribution following intravenous vitamin K1-fat emulsion (VK1 -FE) administration and compared it with that after VK1 injection. Rats were intravenously injected with VK1-FE or VK1 . The organ and tissue VK1 concentrations were determined using high-performance liquid chromatography method at 0.5, 2 and 4 h to determine distribution, equilibrium and elimination phases, respectively. In the VK1-FE group, the plasma, heart and spleen VK1 concentrations decreased over time. However, other organs like liver, lung, kidney, muscle and testis, reached peak VK1 concentrations at 2 h. In the VK1 injection group, the liver VK1 concentrations were significantly higher than those in other organs at the three time points. However, VK1 concentrations in the other organs peaked at 2 h. In addition, in VK1-FE group, the heart, spleen and lung VK1 concentrations were significantly higher than those in the VK1 injection group at the three time points, and the liver VK1 concentration was significantly higher than that in the VK1 injection group at 4 h. The VK1 amount was greatest in the liver compared with the other organs. Thus, the liver is the primary organ for VK1 distribution. The distribution of VK1 is more rapid when injected as VK1-FE than as VK1 .

Simultaneous determination of triamcinolone acetonide palmitate and triamcinolone acetonide in beagle dog plasma by UPLC-MS/MS and its application to a long-term pharmacokinetic study of triamcinolone acetonide palmitate lipid emulsion injection.

In order to investigate the pharmacokinetics of triamcinolone acetonide palmitate (TAP) which is a lipid-soluble prodrug of triamcinolone acetonide (TA), a rapid, simple, sensitive and reproducible UPLC-MS/MS method has been developed and validated for the simultaneous determination of TAP and TA in beagle dog plasma. After simple liquid-liquid extraction, the analytes and internal standard (dexamethasone, DEX) were separated on Phenomenex Luna C18 column (50 mm × 2.1mm, 1.7 µm) using a mobile phase consisting of solvent A (acetonitrile) and solvent B (0.1% ammonia solution) at a flow rate of 0.2 ml/min with gradient elution. Acquisition of mass spectrometric data was performed in multiple reaction monitoring (MRM) mode via positive electrospray ionization using the ion transitions of m/z 673.5→397.3, 435.3→415.3 and 393.3→355.3 for TAP, TA and IS, respectively. The method was of satisfactory specificity, sensitivity, precision and accuracy over the concentration range of 1-1,000 ng/ml for TAP and 0.5-500 ng/ml for TA. The intra- and inter-day precisions for both TAP and TA were 3.2% to 18.7% and the accuracy was in the range of -8.4% to 6.8%. The mean recoveries of TAP, TA and IS were 86.7-104.7%. The method was successfully applied to a long-term pharmacokinetic study of TAP and TA after 28-day repeated intravenous administration of TAP lipid emulsion injection to beagle dogs.

sFLT1 in preeclampsia: trophoblast defense against a decidual VEGFA barrage?

Preeclampsia, a life-threatening complication of human pregnancy, has a spectrum of clinical signs and is likely caused by an array of pathological mechanisms. However, elevated levels of soluble fms-like tyrosine kinase-1 (sFLT1) in the placenta and in the maternal circulation has emerged as a common finding in women with preeclampsia and likely is a causative factor in this disorder. In this issue of the JCI, Fan and colleagues provide experimental evidence from both humans and mice that suggests placental trophoblast cells overexpress sFLT1 in self defense against excessive VEGFA produced by maternal decidual cells. The authors' work thus implicates the decidual cells of the mother as the culprit responsible for increased placental expression of sFLT1, a VEGFA antagonist that enters the maternal circulation and consequently induces the clinical signs of preeclampsia.

Experimental assessment of temperature influence on miriplatin and cisplatin iodized-oil suspension viscosity.

PURPOSE: To evaluate differences in the viscosity of a platinum iodized-oil suspension on the kind of platinum agent and temperature. MATERIALS AND METHODS: Viscosities of a 70 mg miriplatin and 3.5 ml iodized-oil suspension (MO suspension) and that of 100 mg cisplatin and 10 ml iodized-oil suspension (CO suspension) were evaluated at three temperatures: 25, 37, and 50 °C. Iodized-oil was used as the control. Each liquid was injected into a capillary tube and allowed to drip separately. The liquid transit time was measured, and the viscosity of each liquid was calculated at each temperature. RESULTS: The viscosity of each liquid decreased as the temperature increased: 43.3 ± 0.5, 39.2 ± 0.7, and 34.7 ± 0.6 mPa s for MO suspension, 41.3 ± 0.2, 36.9 ± 0.3, and 32.7 ± 0.9 mPa s for CO suspension, and 40.5 ± 0.2, 36.8 ± 0.2, and 33.8 ± 0.7 mPa s for iodized-oil at 25, 37, and 50 °C, respectively. The MO suspension group viscosity was significantly higher than that of the CO suspension group (p < 0.05) and the control (p < 0.05). Significant differences were found in viscosities among groups divided by temperature (25 °C-group vs. 37 °C-group, p < 0.05; 37 °C-group vs. 50 °C-group, p < 0.05). CONCLUSION: The viscosity of the platinum iodized-oil suspension can be adjusted by changing temperature.

Decreased reticuloendothelial system clearance and increased blood half-life and immune cell labeling for nano- and micron-sized superparamagnetic iron-oxide particles upon pre-treatment with Intralipid.

BACKGROUND: Superparamagnetic iron-oxide nanoparticles are useful as contrast agents for anatomical, functional and cellular MRI, drug delivery agents, and diagnostic biosensors. Nanoparticles are generally cleared by the reticuloendothelial system (RES), in particular taken up by Kupffer cells in the liver, limiting particle bioavailability and in-vivo applications. Strategies that decrease the RES clearance and prolong the circulation residence time of particles can improve the in-vivo targeting efficiency. METHODS: Intralipid 20.0%, an FDA approved nutritional supplement, was intravenously administered in rats at the clinical dose (2g/kg) 1h before intravenous injection of ultra-small superparamagnetic iron-oxide (USPIO) or micron-sized paramagnetic iron-oxide (MPIO) particles. Blood half-life, monocyte labeling efficiency, and particle biodistribution were assessed by magnetic resonance relaxometry, flow cytometry, inductively-coupled plasma MS, and histology. RESULTS: Pre-treatment with Intralipid resulted in a 3.1-fold increase in USPIO blood half-life and a 2-fold increase in USPIO-labeled monocytes. A 2.5-fold increase in MPIO blood half-life and a 5-fold increase in MPIO-labeled monocytes were observed following Intralipid pre-treatment, with a 3.2-fold increase in mean iron content up to 2.60pg Fe/monocyte. With Intralipid, there was a 49.2% and 45.1% reduction in liver uptake vs. untreated controls at 48h for USPIO and MPIO, respectively. CONCLUSIONS: Intralipid pre-treatment significantly decreases initial RES uptake and increases in-vivo circulation and blood monocyte labeling efficiency for nano- and micron-sized superparamagnetic iron-oxide particles. GENERAL SIGNIFICANCE: Our findings can have broad applications for imaging and drug delivery applications, increasing the bioavailability of nano- and micron-sized particles for target sites other than the liver.

Soybean oil: a potentially new intravascular perfusate.

BACKGROUND: Given that micelles of lipids are colloids, the hypothesis was generated that the rapid administration of large volumes of soybean oil micelles would be an effective perfusion fluid. We also hypothesized that oxygen loading would be enhanced due to the greater solubility of oxygen in lipids compared to water. METHODS: A 100% lethal mouse model of blood loss was used to compare the ability of soybean oil micelles to that of Ringer's lactate, blood and other fluids, with respect to raising and maintaining the blood pressure for one hour. Oxygen on- and off-loading of various concentrations of soybean oil micelles was determined using mass spectroscopy. Nitric oxide uptake by micelles was also determined in a similar fashion. RESULTS: A 20% soybean oil emulsion was superior to Ringer's lactate in raising and maintaining blood pressure. A 20% soybean oil emulsion with 5% albumin added was superior to shed blood as well as solutions comprised of 5% albumin added to either normal saline or Ringer's lactate. There was a linear relationship between oxygen content and micelle concentration between 10% and 30%. Off-loading of oxygen from the micelles was nearly as fast as off-loading from water. Nitric oxide also loaded preferentially onto soybean oil micelles. CONCLUSIONS: (1) Soybean oil emulsions were superior to other fluids in restoring and maintaining the blood pressure; (2) oxygen-carrying ability of soybean oil micelles exceeds that of water and follows Henry's law between 10% and 30% w/v oil content; (3) nitric oxide was carried by the micelles; (4) animals receiving soybean oil micelles did not exhibit fat embolization; (5) colloids comprised of soybean oil-containing micelles may be used to replace blood loss and may be used to deliver oxygen and other potentially therapeutic gases such as nitric oxide to tissues.

In vitro and in vivo entrapment of bupivacaine by lipid dispersions.

Intravenous lipid emulsion is recommended as treatment for local anesthetic intoxication based on the hypothesis that the lipophilic drug is entrapped by the lipid phase created in plasma. We compared a 15.6 mM 80/20 mol% phosphatidyl choline (PC)/phosphatidyl glycerol (PG)-based liposome dispersion with the commercially available Intralipid® emulsion in a pig model of local anesthetic intoxication. Bupivacaine-lipid interactions were studied by electrokinetic capillary chromatography. Multilamellar vesicles were used in the first in vivo experiment series. This series was interrupted when the liposome dispersion was discovered to cause cardiovascular collapse. The toxicity was decreased by an optimized sonication of the 50% diluted liposome dispersion (7.8 mM). Twenty anesthetized pigs were then infused with either sonicated PC/PG liposome dispersion or Intralipid®, following infusion of a toxic dose of bupivacaine which decreased the mean arterial pressure by 50% from baseline. Bupivacaine concentrations were quantified in blood samples using liquid chromatography/mass spectrometry. No significant difference in the context-sensitive plasma half-life of bupivacaine was detected (p=0.932). After 30 min of lipid infusion, the bupivacaine concentration was 8.2±1.5 mg/L in the PC/PG group and 7.8±1.8 mg/L in the Intralipid® group, with no difference between groups (p=0.591). No difference in hemodynamic recovery was detected between groups (p > 0.05).

Acute hypoxia induces hypertriglyceridemia by decreasing plasma triglyceride clearance in mice.

Obstructive sleep apnea (OSA) induces intermittent hypoxia (IH) during sleep and is associated with elevated triglycerides (TG). We previously demonstrated that mice exposed to chronic IH develop elevated TG. We now hypothesize that a single exposure to acute hypoxia also increases TG due to the stimulation of free fatty acid (FFA) mobilization from white adipose tissue (WAT), resulting in increased hepatic TG synthesis and secretion. Male C57BL6/J mice were exposed to FiO(2) = 0.21, 0.17, 0.14, 0.10, or 0.07 for 6 h followed by assessment of plasma and liver TG, glucose, FFA, ketones, glycerol, and catecholamines. Hypoxia dose-dependently increased plasma TG, with levels peaking at FiO(2) = 0.07. Hepatic TG levels also increased with hypoxia, peaking at FiO(2) = 0.10. Plasma catecholamines also increased inversely with FiO(2). Plasma ketones, glycerol, and FFA levels were more variable, with different degrees of hypoxia inducing WAT lipolysis and ketosis. FiO(2) = 0.10 exposure stimulated WAT lipolysis but decreased the rate of hepatic TG secretion. This degree of hypoxia rapidly and reversibly delayed TG clearance while decreasing [(3)H]triolein-labeled Intralipid uptake in brown adipose tissue and WAT. Hypoxia decreased adipose tissue lipoprotein lipase (LPL) activity in brown adipose tissue and WAT. In addition, hypoxia decreased the transcription of LPL, peroxisome proliferator-activated receptor-γ, and fatty acid transporter CD36. We conclude that acute hypoxia increases plasma TG due to decreased tissue uptake, not increased hepatic TG secretion.

Pharmacokinetic evaluation of pancreatic arterial infusion chemotherapy with lipid emulsion as a drug carrier in an animal model.

The purpose of this study was to investigate the potential pharmacokinetic advantage of pancreatic arterial infusion chemotherapy with lipid emulsion as a drug carrier for pancreatic cancer in a dog model. The 20% Intralipid, as a solvent, was used in the experimental animals with 2 ml/kg (group A) and 1 ml/kg (group B). Normal sodium as a solvent was used as a control with 2 ml/kg (group C) and 1 ml/kg (group D), respectively. Cisplatin (4 mg/kg) was infused into the proximal segment of the splenic artery. The concentrations of cisplatin were measured in plasma of the portal vein and in the liver and pancreas of groups A and C. The area under the concentration-time curve (AUC), the maximum plasma concentration (C(max)), and the elimination half-life (t(1/2)) in plasma were calculated and compared statistically. Compared with group C, the AUC and C(max) of group A were significantly lower (P<0.01 and P<0.01, respectively), the t 1/2 was longer (P<0.05), and the tissue cisplatin concentration of the pancreas was higher (P<0.05). Compared with group D, the AUC and C(max) of group B were significantly lower (P<0.01 and P<0.01, respectively) and the t(1/2) was longer (P<0.01). Pancreatic arterial infusion chemotherapy with lipid emulsion as a drug carrier can increase the local concentration and prolong the retention time of a drug.

Nutritional assessment and delivery in renal replacement therapy patients.

The present review is aimed at illustrating and discussing literature data and recent guidelines concerning artificial nutrition in patients with acute kidney injury (AKI) on renal replacement therapy (RRT). Protein-energy wasting often complicates the clinical course of AKI in critically ill patients, increasing their morbidity and mortality risk. The most severe forms of the syndrome - those observed in ICU patients - are characterized by hypercatabolism with relevant lean body mass loss. In this clinical condition, artificial nutrition (enteral and/or parenteral nutrition) is considered an integral part of the complex therapeutic approach. Even though many issues concerning nutrition in AKI are common to other critically ill patients, the presence of AKI with the ensuing impairment of the kidney homeostatic function introduces specific problems and can make more difficult to give the patient an adequate nutrient provision. Thus, peculiarities of the syndrome - and of RRT itself - must be taken into account in nutritional planning for these patients. Recent guidelines have suggested that the enteral route should be the preferred one, even though parenteral nutrition is often required to target nutritional needs (25-30 kcal/kg body weight/day, and 1.5 + 0.2 g/kg/day to compensate for amino acid losses during RRT). Special attention should be paid to the impact of different forms of RRT on the possible loss of both macro- and micronutrients and vitamins, as well as to the risk of metabolic complications. Finally, close integration between nutritional support and RRT is required, aiming at carefully tailoring both therapies on patient's changing needs.

Treatment of local-anesthetic toxicity with lipid emulsion therapy.

PURPOSE: The use of lipid emulsion to treat local-anesthetic toxicity is discussed. SUMMARY: Systemic toxicity from local anesthetics is a rare but potentially fatal complication of regional anesthesia. There is increasing evidence that lipid emulsion may be an effective treatment to reverse the cardiac and neurologic effects of local-anesthetic toxicity. A literature search identified seven case reports of local-anesthetic toxicity in which lipid emulsion was used. Lipid emulsion was found to be successful in the treatment of local-anesthetic toxicity associated with various regional anesthetic techniques and multiple local anesthetics. The majority of patients in the case reports reviewed were unresponsive to initial management of local-anesthetic toxicity with standard resuscitative measures, but all recovered completely after receiving lipid emulsion therapy. The initial dose of lipid emulsion administered varied among the case reports, as well as whether a lipid emulsion infusion was started and at what point during resuscitation. Based on the case reports reviewed, an initial bolus dose of 1.5 mL/kg followed by an infusion of 10 mL/min as soon as local-anesthetic toxicity is suspected seems most beneficial. The pharmacokinetics of lipid emulsion therapy in the treatment of local-anesthetic toxicity has not been fully elucidated but likely involves increasing metabolism, distribution, or partitioning of the local anesthetic away from receptors into lipid within tissues. CONCLUSION: Lipid emulsion has been reported useful in the treatment of systemic toxicity caused by local anesthetics. The mechanism of effect is unclear, and evidence for the benefit of lipid therapy in humans is from case reports only.

Lipid therapy for serotonin syndrome after intoxication with venlafaxine, lamotrigine and diazepam.

A 44-year-old woman developed coma and seizure activity after intentional ingestion of 200 mg diazepam, 20 g lamotrigine and 4.5 g venlafaxine. In our intensive care unit a distinct rigidity and hyperreflexia was observed. This status was not influenced by haemodialysis which was initiated directly after admission. Plasma concentrations of the ingested drugs were determined before hemodialysis was started (560 µg/L diazepam, 42.4 mg/L lamotrigine and 1254 µg/L venlafaxine). Eight hours after the start of haemodialysis a 150 mL (2.5 mL/kg) intravenous bolus of 20% lipid emulsion was given. Soon after administration of the lipid infusion the distinct rigidity and hyperreflexia disappeared. The further course was uneventful.

Injectable lipid emulsions-advancements, opportunities and challenges.

Injectable lipid emulsions, for decades, have been clinically used as an energy source for hospitalized patients by providing essential fatty acids and vitamins. Recent interest in utilizing lipid emulsions for delivering lipid soluble therapeutic agents, intravenously, has been continuously growing due to the biocompatible nature of the lipid-based delivery systems. Advancements in the area of novel lipids (olive oil and fish oil) have opened a new area for future clinical application of lipid-based injectable delivery systems that may provide a better safety profile over traditionally used long- and medium-chain triglycerides to critically ill patients. Formulation components and process parameters play critical role in the success of lipid injectable emulsions as drug delivery vehicles and hence need to be well integrated in the formulation development strategies. Physico-chemical properties of active therapeutic agents significantly impact pharmacokinetics and tissue disposition following intravenous administration of drug-containing lipid emulsion and hence need special attention while selecting such delivery vehicles. In summary, this review provides a broad overview of recent advancements in the field of novel lipids, opportunities for intravenous drug delivery, and challenges associated with injectable lipid emulsions.