D-Leucine

Purpose: Psychological stress could negatively influence female reproductive ability. d-Leucine (d-Leu) is a d-type amino acid found in foods and mammalian tissues. We have examined the protective effects of d-Leu on oocyte abnormality induced by psychological stress. Methods: Female mice (6-week-old) were divided into three groups: control, restraint stress (RS), and RS/d-Leu. The RS and RS/d-Leu mice were holed for 3 hours daily during 14 days. RS/d-Leu mice were fed 0.3% d-Leu diet. The oocyte maturation failure was analyzed by shapes of spindles and chromosomes. In addition, levels of heme-oxygenase-1 (HO-1) and superoxide dismutase (SOD) expression in the ovaries were also examined. Whether d-Leu reduces the generation of reactive oxygen species (ROS) in cultured cells, K562 cells were treated with d-Leu, and then ROS in K562 were analyzed. Results: Oocyte maturation failure was increased in RS mice. d-Leu reduced abnormal oocytes to control level. The expression levels of HO-1 and SOD2 increased in RS/d-Leu mice compared to those of RS mice. ROS levels were decreased in K562 cells with d-Leu in a dose-dependent manner. Conclusions: We concluded that d-Leu protects oocytes from psychological stress through the induction of HO-1 and SOD2 expression then by reducing oxidative stress.

The objective of the work was to produce a new excipient based on D-leucine to improve the aerosolization properties of the poorly flowable micronized budesonide. The D-leucine powders produced by a nano spray-dryer were characterized in terms of dimensions, morphology, thermal behavior, X-ray powder diffraction and infrared spectroscopy. Then, micronized budesonide was mixed with the different leucine powders obtained or commercial D-leucine at different weight ratios (1:1, 5:1, 10:1) to investigate their aerodynamic characteristics using a glass twin-stage impinger. Commercial D-leucine powder is composed of large flattened crystals of about 30 μm with ~3 μm thickness, while micronized budesonide appeared as small irregular crystals. After spray-drying, D-leucine particles appeared wrinkled and porous. Particle sizes were mainly influenced by the amino acid concentration. Aerodynamic assessment showed that D-leucine was able to improve the aerodynamic behavior of micronized budesonide from about 28 to 45% emitted fraction. The best aerodynamic properties were obtained with D-leucine powdered from a water:ethanol (1:1, v:v) solution and using micronized budesonide:leucine weight ratio of 5:1. The direct physical mixing of the atomized D-leucine with the micronized active pharmaceutical ingredient is a valid and economic alternative for the production of carrier-free dry powders for inhalation.

Background: Current medicines do not provide sufficient seizure control for nearly one-third of patients with epilepsy. New options are needed to address this treatment gap. We recently found that the atypical amino acid d-leucine protected against acutely-induced seizures in mice, but its effect in chronic seizures has not been explored. We hypothesized that d-leucine would protect against spontaneous recurrent seizures. We also investigated whether mice lacking a previously-described d-leucine receptor (Tas1R2/R3) would be protected against acutely-induced seizures. Methods: Male FVB/NJ mice were subjected to kainic acid-induced status epilepticus and monitored by video-electroencephalography (EEG) (surgically implanted electrodes) for 4weeks before, during, and after treatment with d-leucine. Tas1R2/R3 knockout mice and controls underwent the maximal electroshock threshold (MES-T) and 6-Hz tests. Results: There was no difference in number of calendar days with seizures or seizure frequency with d-leucine treatment. In an exploratory analysis, mice treated with d-leucine had a lower number of dark cycles with seizures. Tas1R2/R3 knockout mice had elevated seizure thresholds in the MES-T test but not the 6-Hz test. Conclusions: d-Leucine treatment was ineffective against chronic seizures after kainic acid-induced status epilepticus, but there was some efficacy during the dark cycle. Because d-leucine is highly concentrated in the pineal gland, these data suggest that d-leucine may be useful as a tool for studying circadian patterns in epilepsy. Deletion of the Tas1R2/R3 receptor protected against seizures in the MES-T test and, therefore, may be a novel target for treating seizures.