Is urethane-chloralose anaesthesia appropriate for pharmacokinetic-pharmacodynamic assessment? Studies with carvedilol

MicroRNA-205-5p Targets HMGB1 to Suppress Inflammatory Responses during Lung Injury after Hip Fracture

Hip fracture is the most common type of injury in elderly people and is associated with a high incidence of complications and risk of mortality. In these patients, subsequent pulmonary infection can contribute to the development of an acute lung injury, a consequence of the systemic inflammatory response induced by hip fracture. Although the crucial role of microRNAs (miRNAs) in inflammatory responses has been established, the functions of miRNAs in the inflammatory responses associated with lung injury after hip fracture remain poorly understood. In this study, we explored the potential role of miR-205-5p in lung injury after hip fracture in an in vivo hip fracture model and in vitro cultures of human pulmonary alveolar epithelial cells (HPAEpiC). An analysis of clinical serum samples revealed increased levels of miR-205-5p and high mobility group box 1 (HMGB1) after hip fracture. A bioinformatics analysis and dual-luciferase reporter assay identified HMGB1 as a potential target of miR-205-5p. The overexpression of miR-205-5p clearly reduced the expression of HMGB1 and inhibited NF-κB signaling, apoptosis, and proinflammatory cytokine production while enabling continued cell proliferation. Our results demonstrate that the upregulation of miR-205-5p suppresses inflammatory responses and promotes cell viability and proliferation by selectively targeting HMGB1 in the context of lung injury after hip fracture. Therefore, miR-205-5p may be an alternative target of therapeutic strategies for lung injury after hip fracture.

[Assessment for antihypertensive drug intake in France in 2019 and adherence]

Non-adherence to antihypertensive treatment is one of the critical contributors to sub-optimal blood pressure control. The French Society of Hypertension remembered that urine and serum biochemical detection of antihypertensive drugs could be useful in a patient with resistant hypertension. Talking to a patient with biochemically confirmed non-adherence to blood pressure-lowering therapy and repeating them improved adherence to drugs. Despite its usefulness, biochemical detection of antihypertensive drugs is not routinely effective in France as they are not reimbursed by French Medical Care, except in patients attending hospitals. The list of blood pressure-lowering drugs able to be biochemically detected in France and their modalities are recorded here.

Novel carvedilol paediatric nanomicelle formulation: in-vitro characterization and in-vivo evaluation

Objectives

Carvedilol (CAR) is a poorly water-soluble beta-blocker. Its encapsulation within nanomicelles (NMs) could improve drug solubility and its oral bioavailability, allowing the development of a paediatric liquid CAR formulation with commercially available copolymers: D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) and poly(vinyl caprolactam)-poly(vinyl acetate)-poly(ethylene glycol) (Soluplus®).

Methods

Drug-loaded NMs were prepared by copolymer and CAR dispersion in distilled water. Micellar size and morphology were characterized by dynamic light scattering and transmission electron microscopy, respectively. In-vitro drug permeation studies were evaluated by conventional gut sac method. In-vivo CAR oral bioavailability from NMs dispersions and drug control solution was evaluated in Wistar rats.

Key findings

Carvedilol apparent aqueous solubility was increased (up to 60.4-folds) after its encapsulation within NMs. The micellar size was ranged between 10.9 and 81.9 nm with a monomodal size distribution. There was a significant enhancement of CAR relative oral bioavailability for both copolymers vs a micelle-free drug solution (P < 0.05). This improvement was higher for TPGS-based micelles (4.95-fold) in accordance with the in-vitro CAR permeation results.

Conclusions

The present investigation demonstrates the development of highly concentrated CAR liquid micellar formulation. The improvement on drug oral bioavailability contributes to the potential of this NMs formulation to enhance CAR paediatric treatment.

Intraperitoneal co-administration of low dose urethane with xylazine and ketamine for extended duration of surgical anesthesia in rats

Procedures involving complex surgical techniques in rats, such as placement of abdominal aortic graft require extended duration of surgical anesthesia, which often can be achieved by repeated administrations of xylazine-ketamine combination. However such repeated anesthetic administration, in addition to being technically challenging, may be associated with potential adverse events due to cumulative effects of anesthesia. We report here the feasibility of using urethane at low dose (~1/10 the recommended anesthetic dose) in combination with a xylazine-ketamine mix to achieve an extended duration of surgical anesthesia in rats. The anesthesia induction phase was quick and smooth with an optimal phase of surgical anesthesia achieved for up to 90 minutes, which was significantly higher compared to that achieved with use of only xylazine-ketamine combination. The rectal temperature, heart rate and respiratory rate were within the physiological range with an uneventful recovery phase. Post surgery the rats were followed up to 3 months without any evidence of tumor or any other adverse effects related to the use of the urethane anesthetic combination. We conclude that low dose urethane can be effectively used in combination with xylazine and ketamine to achieve extended duration of surgical anesthesia up to 90 minutes in rats.

Pharmacokinetics of isoforskolin after administration via different routes in guinea pigs

1. The objective of this study was to characterize the pharmacokinetics of isoforskolin after oral, intraperitoneal and intravenous administration, as well as to compare bioavailability. 2. Isoforskolin was administered to guinea pigs at a dose of 2 mg/kg. Plasma concentrations were determined by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) method. The pharmacokinetic parameters were calculated by a noncompartmental method. A compartment model was also adopted to describe the pharmacokinetic profiles. 3. The pharmacokinetic behavior of intravenously administered isoforskolin was characterized by rapid and extensive distribution (V_z = 16.82 ± 8.42 L/kg) followed by rapid elimination from the body (Cl = 9.63 ± 4.21 L/kg/h). After intraperitoneal administration, isoforskolin was absorbed rapidly (T_max = 0.12 ± 0.05 h). The pharmacokinetic profiles of isoforskolin were similar after intraperitoneal and intravenous administration, except for the concentrations at the initial sampling times. Isoforskolin was also absorbed rapidly following oral dosing; however, the concentration-time data were best fit to a one-compartment model, which was different from that observed after intravenous and intraperitoneal administration. Following intraperitoneal and oral administration, the absolute bioavailability of isoforskolin was 64.12% and 49.25%, respectively. 4. Isoforskolin is a good candidate for oral administration because of its good oral bioavailability.

Interaction of acupuncture and electroacupuncture on the pharmacokinetics of aspirin and the effect of brain blood flow in rats

Acupuncture and electroacupuncture have been used to improve the brain and motor functions of poststroke patients, and aspirin is used for the prevention of stroke recurrence. Our hypothesis is that acupuncture and electroacupuncture treatments may interact with aspirin in terms of pharmacokinetics via affecting the brain blood flow. The aim of this study is to investigate the potential interactions of acupuncture and electroacupuncture on the pharmacokinetics of aspirin. The effects of acupuncture treatments on brain blood flow were measured by the laser Doppler blood flow imager. The parallel pharmacokinetic study design included three groups: control, acupuncture, and electroacupuncture groups. Two acupoints, namely, Quchi (LI 11) and Zusanli (ST 36), were needled and stimulated electronically in anaesthetized rats. The concentrations of aspirin and its metabolite, salicylic acid were determined by microdialysis and HPLC analysis after aspirin administration (30 mg/kg, i.v.). The brain blood flow responded to electroacupuncture treatments, but the pharmacokinetic parameters of aspirin and salicylic acid in blood and brain were not significantly changed by acupuncture and electroacupuncture treatments. This study may, in part, offer some evidence to support the contention that there is no significant interaction for the combination of aspirin with acupuncture or electroacupuncture.

Increase in plasma ACTH induced by urethane is not a consequence of hyperosmolality

Although anesthetic doses of urethane increase plasma levels of ACTH, the exact mechanism through which this occurs is unclear. We theorized that these increases might be a consequence of an increased systemic osmolality owing to the large doses of urethane usually employed. To evaluate this possibility, we measured plasma osmolality and ACTH in a total of six rats after graded infusions of urethane (N=3 rats) or equimolar amounts of mannitol (N=3 rats). Rats received infusions at 15 min intervals up to a cumulative dose equivalent to an anesthetic dose for urethane (1.4 g/kg). Blood samples (0.35 ml) were withdrawn at baseline and 10 min after each infusion. Urethane and mannitol produced significant and equivalent increases in plasma osmolality. However, only urethane evoked increases in plasma ACTH which were maximal (252+/-55 pg/ml from a baseline of 27+/-7 pg/ml) after a cumulative dose of 1 g/kg. Thus, increases in plasma ACTH seen after anesthetic doses of urethane are unlikely to be a consequence of its effect on plasma osmolality.