Effects of the sigma-1 receptor agonist blarcamesine in a murine model of fragile X syndrome: neurobehavioral phenotypes and receptor occupancy

Fragile X syndrome (FXS), a disorder of synaptic development and function, is the most prevalent genetic form of intellectual disability and autism spectrum disorder. FXS mouse models display clinically-relevant phenotypes, such as increased anxiety and hyperactivity. Despite their availability, so far advances in drug development have not yielded new treatments. Therefore, testing novel drugs that can ameliorate FXS' cognitive and behavioral impairments is imperative. ANAVEX2-73 (blarcamesine) is a sigma-1 receptor (S1R) agonist with a strong safety record and preliminary efficacy evidence in patients with Alzheimer's disease and Rett syndrome, other synaptic neurodegenerative and neurodevelopmental disorders. S1R's role in calcium homeostasis and mitochondrial function, cellular functions related to synaptic function, makes blarcamesine a potential drug candidate for FXS. Administration of blarcamesine in 2-month-old FXS and wild type mice for 2 weeks led to normalization in two key neurobehavioral phenotypes: open field test (hyperactivity) and contextual fear conditioning (associative learning). Furthermore, there was improvement in marble-burying (anxiety, perseverative behavior). It also restored levels of BDNF, a converging point of many synaptic regulators, in the hippocampus. Positron emission tomography (PET) and ex vivo autoradiographic studies, using the highly selective S1R PET ligand [18F]FTC-146, demonstrated the drug's dose-dependent receptor occupancy. Subsequent analyses also showed a wide but variable brain regional distribution of S1Rs, which was preserved in FXS mice. Altogether, these neurobehavioral, biochemical, and imaging data demonstrates doses that yield measurable receptor occupancy are effective for improving the synaptic and behavioral phenotype in FXS mice. The present findings support the viability of S1R as a therapeutic target in FXS, and the clinical potential of blarcamesine in FXS and other neurodevelopmental disorders.

GABA Measurement in a Neonatal Fragile X Syndrome Mouse Model Using 1H-Magnetic Resonance Spectroscopy and Mass Spectrometry

Fragile X syndrome (FXS) is the leading monogenetic cause of autism spectrum disorder and inherited cause of intellectual disability that affects approximately one in 7,000 males and one in 11,000 females. In FXS, the Fmr1 gene is silenced and prevents the expression of the fragile X mental retardation protein (FMRP) that directly targets mRNA transcripts of multiple GABAA subunits. Therefore, FMRP loss adversely impacts the neuronal firing of the GABAergic system which creates an imbalance in the excitatory/inhibitory ratio within the brain. Current FXS treatment strategies focus on curing symptoms, such as anxiety or decreased social function. While treating symptoms can be helpful, incorporating non-invasive imaging to evaluate how treatments change the brain's biology may explain what molecular aberrations are associated with disease pathology. Thus, the GABAergic system is suitable to explore developing novel therapeutic strategies for FXS. To understand how the GABAergic system may be affected by this loss-of-function mutation, GABA concentrations were examined within the frontal cortex and thalamus of 5-day-old wild type and Fmr1 knockout mice using both 1H magnetic resonance imaging (1H-MRS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Our objective was to develop a reliable scanning method for neonatal mice in vivo and evaluate whether 1H-MRS is suitable to capture regional GABA concentration differences at the front end of the critical cortical period where abnormal neurodevelopment occurs due to FMRP loss is first detected. 1H-MRS quantified GABA concentrations in both frontal cortex and thalamus of wild type and Fmr1 knockout mice. To substantiate the results of our 1H-MRS studies, in vitro LC-MS/MS was also performed on brain homogenates from age-matched mice. We found significant changes in GABA concentration between the frontal cortex and thalamus within each mouse from both wild type and Fmr1 knockout mice using 1H-MRS and LC-MS/MS. Significant GABA levels were also detected in these same regions between wild type and Fmr1 knockout mice by LC-MS/MS, validating that FMRP loss directly affects the GABAergic system. Thus, these new findings support the need to develop an effective non-invasive imaging method to monitor novel GABAergic strategies aimed at treating patients with FXS.

TRANSPLANTATION OF HYPERTHERMIC PRECONDITIONING OLFACTORY ENSHEATHING CELLS COMBINED WITH NEURAL STEM CELLS IN THE TREATMENT OF CENTRAL NERVE INJURY

This study aims to observe the effect of the transplantation of hyperthermic preconditioning (HPC) olfactory ensheathing cells (OECs) at 40°C combined with neural stem cells (NSCs) in the treatment of spinal cord injury (SCI), based on the OECs and NSCs taken from the olfactory bulbs and cerebral cortex of newborn rats. Forty-two female Sprague Dawley (SD) rats were randomly divided into: control group, NSCs+OECs without HPC group and NSCs+HPC OECs group. Firstly, hemisected spinal cord injury model was established; the motor function recovery of the right lower limb of the rats was compared by Basso-Beatie-Bresnahan rating (BBB rating), climbing score and running time on a rotating platform during the whole experiment. At one day, two weeks and four weeks after transplantation, two rats were randomly selected from each group for section preparation. Hematoxylin and eosin (HE) staining was performed on the sections to observe and analyze the pathological changes of the spinal cord tissue, and bromodeoxyuridine (BrdU) labeling was used to observe the distribution of transplanted cells. The results demonstrated that, BBB score of the rats that were treated by transplantation of NSCs combined with HPC OCEs was distinctly improved; a rapid increase of BBB score was found two weeks after transplantation, while BBB score had slightly increased six weeks later. BBB score of the control group and the NSCs+OECs without HPC group was found with a slight increase, especially in the control group. BBB score of NSCs+HPC OECs was significantly higher than in the control group and the NSCs+OECs without HPC group at the 2nd, 4th, 6th, 8th and 12th week after treatment (P<0.05). Climbing tests and detection of running time after 4 weeks and 6 weeks demonstrated that, the recovery of limb function of the NSCs+HPC OECs group was better than the other groups (P<0.05). HE staining results of NSCs+HPC OECs indicated that, cells of the spinal cord were neatly arranged, close to normal. BrdU labeling results revealed that, transplanted cells were found in injury tissue, indicating that they were involved in the spinal cord repair. This study proves that, the effect of NSCs combined with HPC OECs in the treatment of SCI is better than NSCs combined with OECs without HPC, and the ratio of NSCs differentiating to neuron after inducing HPC OECs supernate is higher than that after inducing OECs supernate without HPC.

Clinical research of persimmon leaf extract and ginkgo biloba extract in the treatment of vertebrobasilar insufficiency

This paper aims to compare the curative effects of persimmon leaf extract and ginkgo biloba extract in the treatment of headache and dizziness caused by vertebrobasilar insufficiency. Sixty patients were observed, who underwent therapy with persimmon leaf extract and ginkgo biloba extract based on the treatment of nimodipine and aspirin. After 30 days, 30 patients treated with persimmon leaf extract and 30 patients with ginkgo biloba extract were examined for changes in hemodynamic indexes and symptoms, such as headache and dizziness. The results showed statistically significant differences of 88.3% for the persimmon leaf extract and 73.1% for the ginkgo biloba extract, P < 0.05. Compared to the group of ginkgo biloba extract, the group of persimmon leaf extract had more apparent improvement in the whole blood viscosity, plasma viscosity, fibrinogen, hematokrit, and platelet adhesion rate, and the difference was statistically significant (P < 0.05 or P < 0.01). Based on these analyses, it can be concluded that persimmon leaf extract is better than ginkgo biloba extract in many aspects, such as cerebral circulation improvement, cerebral vascular expansion, hypercoagulable state lowering and vertebrobasilar insufficiency-induced headache and dizziness relief.

Full-valve annuloplasty in treatment of primary deep venous valvular incompetence of the lower extremities

Full-valve annuloplasty of superficial femoral venous valves was performed successfully in 139 extremities affected with primary deep venous incompetence of the lower limb. Chronic ulcerations in 43 affected extremities healed after operation. Postoperative venography showed that the recovery rate of valvular function was 97%, and no serious complication was noted. Follow-up for a mean of 3.5 years showed no varicosed vein and no recurrence of ulceration. The principles of operation, the optimum site, number and degree of annuloplasty, indications and results of the operation were discussed.