Effects of heparin and low molecular weight heparin on lipid transport during parenteral feeding in the rat

Heparin Increases Food Intake through AgRP Neurons

Although the widely used anticoagulant drug heparin has been shown to have many other biological functions independent of its anticoagulant role, its effects on energy homeostasis are unknown. Here, we demonstrate that heparin level is negatively associated with nutritional states and that heparin treatment increases food intake and body weight gain. By using electrophysiological, pharmacological, molecular biological, and chemogenetic approaches, we provide evidence that heparin increases food intake by stimulating AgRP neurons and increasing AgRP release. Our results support a model whereby heparin competes with insulin for insulin receptor binding on AgRP neurons, and by doing so it inhibits FoxO1 activity to promote AgRP release and feeding. Heparin may be a potential drug target for food intake regulation and body weight control.

Zhu et al. demonstrate that heparin competes with insulin for insulin receptor binding on AgRP neurons, and by doing so it inhibits FoxO1 activity to promote AgRP release and feeding. Heparin is identified as a potential drug target for food intake regulation and body weight control.

Evaluation of intravenous lipid emulsion on haloperidol-induced hypotension in rabbits

There are many reports on the effects of intravenous lipid emulsion (ILE) as an antidote in drug toxicity. Haloperidol (HAL) is a butyrophenone antipsychotic agent which is highly lipophilic. Hypotension is an important adverse effect of HAL administration and overdose. The aim of this study was to investigate the beneficial hemodynamic effects of ILE on acute HAL poisoning. We used six groups of five male rabbits. Two groups received aseptic distilled water intravenously followed by infusion of 18.6 ml/kg normal saline, as negative control group, or ILE 20% after 0.5 h. The third group received 18.6 ml/kg normal saline after HAL infusion (2.6 mg/kg). The other three groups received ILE 20% solution (6, 12, and 18.6 ml/kg) following HAL (2.6 mg/kg) administration. We measured blood pressure at 0, 0.5, 1, 2, 3, 4, 8, and 24 h after starting HAL administration, from left forelimb using a noninvasive method that was carried out automatically with a neonatal intensive care unit bedside monitor. ILE 20% at the dose of 18 ml/kg could return the reduced mean arterial pressure and diastolic blood pressure sooner than the other doses and normal saline. In conclusion, ILE could reverse HAL-induced hypotension same as the other lipophilic drugs. However, the clinical use of ILE for this purpose needs more evaluation to determine its exact indication and safety.

Randomized controlled trial of heparin for prevention of blockage of peripherally inserted central catheters in neonates

AIM

To determine whether the addition of heparin to total parenteral nutrition (TPN) fluid would prevent blockage of peripherally inserted central catheters (PICCs) in neonates.

METHODS

This was a randomized, double-blind, controlled study of 66 eligible neonates with PICCs inserted for the administration of TPN. Infants were randomized to receive TPN containing either 1 IU ml(-1) of heparin (n = 35) or no heparin (n = 31).

RESULTS

There was no significant difference in the incidence of blocked catheters between the two groups of infants (heparin: 14.3%; no-heparin: 22.6%, p = 0.4). Although a higher percentage (62.9%) of infants in the heparin group received a complete course of TPN successfully via PICC than those in the no-heparin group (48.4%), the difference was not statistically significant (p = 0.3). There were no significant differences in the incidence of catheter-related sepsis, hypertriglyceridaemia, hyperbilirubinaemia, coagulopathy or intraventricular haemorrhage between the two groups.

CONCLUSION

Addition of heparin to TPN fluid was not associated with a significant reduction in the incidence of blocked PICCs. However, the sample size of this study was too small to exclude even rather marked differences between the groups.

[From fat emboli to fat embolism syndrome]

The occurrence of a fat embolism syndrome (FES) can be explained by two hypothetic mechanisms. In the mechanical hypothesis, bone marrow enters into the cardiovascular system during an intramedullary peak pressure. This peak could occur during either long bone fracture and/or intramedullary nailing or cemented or noncemented arthroplasty. According to the biochemical hypothesis, the FES could occur in nontraumatic conditions such as lipid emulsion infusion or sickle cell disease. The C-reactive protein is a possible factor for destabilizing plasma fat (chylomicrons or Intralipid liposomes). Treatment with heparin has been reported to interfere with lipid metabolism through a "creaming" phenomenon. Plasma fatty acids increase lipid peroxidation, with potential severe oxidative stress of lung. Vascular lung injury is increased by granulocytes and the clotting cascade is activated by neutral fat. After a symptom-free period, the full clinical picture is characterized by pulmonary insufficiency with hypoxaemia, neurological impairment, pyrexia and petechial haemorrhages. The accurate incidence cannot be assessed as many subclinical forms remain unrecognized. Transoesophageal echocardiography with color-flow Doppler allows considerable insight into the sequence of embolic events and patent foramen ovale (PFO). A PFO induces an increase in right-to-left shunt in case of an elevated intrapulmonary pressure. PFO might elicit systemic manifestations of the FES, particularly with neurological impairment. Carotid ultrasonography helps to visualize embolism. Magnetic resonance imaging of cerebral fat emboli is a better diagnostic tool for detecting brain embolism than computerized tomography. Quantification of cells containing fat droplets in bronchoalveolar lavage material could also be helpful. Pulmonary microvascular cytology analysis of capillary blood samples obtained through a pulmonary artery catheter in combination with blood gas changes are of value for earlier stage FES. Prophylactic and therapeutic measures are aimed to counteract the various mechanisms leading to FES. The decrease in time delay of fracture management is probably the most effective prophylactic means. A reaming procedure can be noxious, particularly in a patient with a severe thoracic trauma. The insertion without reaming of a small diameter nail, plating or external fixation have several advantages. Albumin infusion is recommended for restoration of blood volume and binding of fatty acids. Among pharmacologic measures, only corticosteroids have a proven benefit, not only for prophylaxis but also for therapy. Aprotinin and heparin are beneficial in counteracting blood cell aggregation. A prophylactic use of vena cava filters has been advocated. Prevention or early treatment of hypovolaemia and hypoxaemia are essential.

Biochemical and ultra-structural reactions to parenteral nutrition with two different fat emulsions in rats

OBJECTIVE

To compare the effects on fat metabolism and Kupffer cell morphology by total parenteral nutrition (TPN) with two different fat emulsions.

DESIGN

Thirty-two male Sprague-Dawley rats, divided into three groups, were investigated. Rats fed orally were used as a reference group, and a group of rats receiving TPN with fat emulsions containing pure long-chain triglycerides (LCT) was compared to a group of rats receiving fat emulsions containing both long-chain triglycerides and medium-chain triglycerides (MCT/LCT). The TPN regimens were equicaloric and administered continuously via a jugular catheter for 10 days.

INTERVENTIONS

After suffocation, blood of the rats was collected for the determination of serum lipids. Epididymal fat and heart were collected for the analysis of lipoprotein lipase (LPL) activities, and liver specimens were saved for analyses of hepatic triglyceride concentration, as well as activities of hepatic lipase (HL) and lysosomal enzymes. Light and electron microscopy were used for examination of the Kupffer cell reaction.

RESULTS

Directly after termination of parenteral feeding, the levels of serum triglycerides and high density lipoprotein (HDL) triglycerides were higher in the MCT/LCT group than in the LCT group, while no differences concerning cholesterol and phospholipid concentrations were found. No significant difference in liver steatosis was found between the two TPN groups. Comparison of the TPN groups showed that the MCT/ LCT group had significantly decreased LPL activity in adipose tissue, while the LCT group had significantly increased LPL activity in the heart. The activity of HL was low in both groups, but significantly lower in the LCT group. Lipid accumulation and an increased number of lysosomes were found in all Kupffer cell when TPN with LCTemulsions was used. Moreover, TPN induced a pronounced increase in various liver lysosomal enzyme activities, but there was no notable difference between LCT and MCT/LCT effects.

CONCLUSIONS

Compared to treatment with pure LCTemulsions, treatment with MCT/LCT emulsions evoked weaker biochemical reactions in terms of lower activity of lipoprotein lipase in fat and heart together with higher serum and HDL triglyceride levels. Morphological signs of increased Kupffer cell activity such as the appearance of multiple lysosomes and fat vacuoles in the cytoplasm followed treatment with pure LCT emulsions. However, both TPN groups showed a marked increase in activities of liver lysosomal enzymes.