Low caveolin-1 levels and symptomatic intracranial haemorrhage risk in large-vessel occlusive stroke patients after endovascular thrombectomy

BACKGROUND AND PURPOSE

Caveolin-1 (Cav-1) is reported to mediate blood-brain barrier integrity after ischaemic stroke. Our purpose was to assess the role of circulating Cav-1 levels in predicting symptomatic intracranial haemorrhage (sICH) amongst ischaemic stroke patients after endovascular thrombectomy (EVT).

METHODS

Patients with large-vessel occlusive stroke after EVT from two stroke centres were prospectively included. Serum Cav-1 level was tested after admission. sICH was diagnosed according to the Heidelberg Bleeding Classification.

RESULTS

Of 325 patients (mean age 68.6 years; 207 men) included, 47 (14.5%) were diagnosed with sICH. Compared with patients without sICH, those with sICH had a lower concentration of Cav-1. After adjusting for potential confounders, multivariate regression analysis demonstrated that the increased Cav-1 level was associated with a lower sICH risk (odds ratio 0.055; 95% confidence interval 0.005-0.669; p = 0.038). Similar results were obtained when Cav-1 levels were analysed as a categorical variable. Using a logistic regression model with restricted cubic splines, a linear and negative association of Cav-1 concentration was found with sICH risk (p = 0.001 for linearity). Furthermore, the performance of the conventional risk factors model in predicting sICH was substantially improved after addition of the Cav-1 levels (integrated discrimination index 2.7%, p = 0.002; net reclassification improvement 39.7%, p = 0.007).

CONCLUSIONS

Our data demonstrate that decreased Cav-1 levels are related to sICH after EVT. Incorporation of Cav-1 into clinical decision-making may help to identify patients at a high risk of sICH and warrants further consideration.

Lamotrigine protects against cognitive deficits, synapse and nerve cell damage, and hallmark neuropathologies in a mouse model of Alzheimer’s disease

Lamotrigine (LTG) is a widely used drug for the treatment of epilepsy. Emerging clinical evidence suggests that LTG may improve cognitive function in patients with Alzheimer’s disease. However, the underlying molecular mechanisms remain unclear. In this study, amyloid precursor protein/presenilin 1 (APP/PS1) double transgenic mice were used as a model of Alzheimer’s disease. Five-month-old APP/PS1 mice were intragastrically administered 30 mg/kg LTG or vehicle once per day for 3 successive months. The cognitive functions of animals were assessed using Morris water maze. Hyperphosphorylated tau and markers of synapse and glial cells were detected by western blot assay. The cell damage in the brain was investigated using hematoxylin and eosin staining. The levels of amyloid-β and the concentrations of interleukin-1β, interleukin-6 and tumor necrosis factor-α in the brain were measured using enzyme-linked immunosorbent assay. Differentially expressed genes in the brain after LTG treatment were analyzed by high-throughput RNA sequencing and real-time polymerase chain reaction. We found that LTG substantially improved spatial cognitive deficits of APP/PS1 mice; alleviated damage to synapses and nerve cells in the brain; and reduced amyloid-β levels, tau protein hyperphosphorylation, and inflammatory responses. High-throughput RNA sequencing revealed that the beneficial effects of LTG on Alzheimer’s disease-related neuropathologies may have been mediated by the regulation of Ptgds, Cd74, Map3k1, Fosb, and Spp1 expression in the brain. These findings revealed potential molecular mechanisms by which LTG treatment improved Alzheimer’s disease. Furthermore, these data indicate that LTG may be a promising therapeutic drug for Alzheimer’s disease.

The Alzheimer’s disease-associated gene TREML2 modulates inflammation by regulating microglia polarization and NLRP3 inflammasome activation

Triggering receptor expressed on myeloid cells-like 2 (TREML2) is a newly identified susceptibility gene for Alzheimer’s disease (AD). It encodes a microglial inflammation-associated receptor. To date, the potential role of microglial TREML2 in neuroinflammation in the context of AD remains unclear. In this study, APP/PS1 mice were used to investigate the dynamic changes of TREML2 levels in brain during AD progression. In addition, lipopolysaccharide (LPS) stimulation of primary microglia as well as a lentivirus-mediated TREML2 overexpression and knockdown were employed to explore the role of TREML2 in neuroinflammation in the context of AD. Our results show that TREML2 levels gradually increased in the brains of APP/PS1 mice during disease progression. LPS stimulation of primary microglia led to the release of inflammatory cytokines including interleukin-1β, interleukin-6, and tumor necrosis factor-α in the culture medium. The LPS-induced microglial release of inflammatory cytokines was enhanced by TREML2 overexpression and was attenuated by TREML2 knockdown. LPS increased the levels of microglial M1-type polarization marker inducible nitric oxide synthase. This effect was enhanced by TREML2 overexpression and ameliorated by TREML2 knockdown. Furthermore, the levels of microglial M2-type polarization markers CD206 and ARG1 in the primary microglia were reduced by TREML2 overexpression and elevated by TREML2 knockdown. LPS stimulation increased the levels of NLRP3 in primary microglia. The LPS-induced increase in NLRP3 was further elevated by TREML2 overexpression and alleviated by TREML2 knockdown. In summary, this study provides the first evidence that TREML2 modulates inflammation by regulating microglial polarization and NLRP3 inflammasome activation. These findings reveal the mechanisms by which TREML2 regulates microglial inflammation and suggest that TREML2 inhibition may represent a novel therapeutic strategy for AD.

Phase 1 dose-escalation study of a siRNA targeting the RTP801 gene in age-related macular degeneration patients

BACKGROUND

To evaluate the safety, tolerability, pharmacokinetics, and dose-limiting toxicities of a single intravitreal (IVT) injection of PF-04523655, a 19-nucleotide, O-methyl stabilized, double-stranded small interfering ribonucleic acid targeting the RTP801 gene in patients with neovascular age-related macular degeneration (AMD).

METHODS

Prospective, phase 1, clinical multicentre trial, enrolled 27 patients with neovascular AMD unresponsive to prior treatment and best corrected visual acuity (BCVA) ≤ 20/200 in the study eye in stratum 1: (dose-escalating, open-label: 50 to 3000 μg of PF-04523655) and 27 patients who had potential to benefit from therapy and BCVA of ≤ 20/100 and ≥ 20/800 in stratum 2 (parallel, masked study of 1000, 1500, 2250, and 3000 μg of PF-04523655). The primary outcome was safety and tolerability assessment as well as pharmacokinetic profiling following a single IVT injection of PF-04523655.

RESULTS

Doses of PF-04523655 ≥ 400 μg were generally detectable in the plasma at 1, 4, and 24 h post-injection. And all doses were below the lowest level of quantification by day 14. A single IVT injection of 50 to 3000 μg of PF-045237655 was generally safe and well tolerated over 24 months. There were no dose-limiting toxicities.

CONCLUSION

A single IVT injection of PF-0523655 ≤ 3000 μg seems safe and well tolerated in eyes with neovascular AMD.

Response surface optimization of microwave-assisted extraction for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii

Microwave-assisted extraction was optimized with response surface methodology for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii. The optimized extraction procedure was achieved by soaking the sample with 70% methanol (1:15, v/v) for 30 min, and then microwave irradiation for 11 min at a power of 600 W. Coupling the extraction process with HPLC-fluorescence presented good recovery, satisfactory precision, and good linear relation. Compared with a method from the Chinese Pharmacopoeia, the proposed method enables higher extraction efficiency and more aecurate analytical results. It can be of Potential value in quality assessment of Radix Puerariae thomsonii medicinal materials.

Animal models of traumatic brain injury: is there an optimal model to reproduce human brain injury in the laboratory?

Compared to other neurological diseases, the research surrounding traumatic brain injury (TBI) has a more recent history. The establishment and use of animal models of TBI remains vital to understand the pathophysiology of this highly complex disease. Such models share the ultimate goals of reproducing patterns of tissue damage observed in humans (thus rendering them clinically relevant), reproducible and highly standardised to allow for the manipulation of individual variables, and to finally explore novel therapeutics for clinical translation. There is no doubt that the similarity of cellular and molecular events observed in human and rodent TBI has reinforced the use of small animals for research. When confronted with the choice of the experimental model it becomes clear that the ideal animal model does not exist. This limitation derives from the fact that most models mimic either focal or diffuse brain injury, whereas the clinical reality suggests that each patient has an individual form of TBI characterised by various combinations of focal and diffuse patterns of tissue damage. This is additionally complicated by the occurrence of secondary insults such as hypotension, hypoxia, ischaemia, extracranial injuries, modalities of traumatic events, age, gender and heterogeneity of medical treatments and pre-existing conditions. This brief review will describe the variety of TBI models available for laboratory research beginning from the most widely used rodent models of focal brain trauma, to complex large species such as the pig. In addition, the models mimicking diffuse brain damage will be discussed in relation to the early primate studies until the use of most common rodent models to elucidate the intriguing and less understood pathology of axonal dysfunction. The most recent establishment of in vitro paradigms has complemented the in vivo modelling studies offering a further cellular and molecular insight of this pathology.

Leptomeningeal disease from oligodendroglioma: Clinical and molecular analysis

2019

Background: Leptomeningeal disease (LMD) is a late complication of malignant glioma, mostly of glioblastoma, that usually responds poorly to treatment and is rapidly fatal. A long surviving case led us to review our experience with LMD in patients with oligodendrogliomas. Methods: A 10-year retrospective chart review was performed. Patients with both oligodendroglial tumors and LMD were identified. A single neuro-pathologist reviewed all histological sections, a single neuro-radiologist reviewed all available images and 1p/19q status was assessed. Results: Seven patients with an oligodendroglioma and LMD were identified. Six were male. Median age at tumor diagnosis was 41 years (range, 28–50). None had radiographic or pathological evidence of leptomeningeal or subependymal tumor at initial diagnosis. Most patients had pure anaplastic oligodendrogliomas (4/7); 6/7 had 1p/19q co-deletion. The median time to first relapse was 41 months (range, 19–127). LMD was diagnosed at first relapse in one case and subsequently in six. The median time to LMD was 76 months (range, 19–151) from initial diagnosis and 28 months (range, 0–36) from first relapse, respectively. LMD treatments included spinal radiation and intrathecal and systemic chemotherapy. After progression, some patients with LMD remained stable clinically. The median survival from initial diagnosis was 104 months (range, 19–183) and from LMD diagnosis was 32 months (range, 2–43). Conclusions: LMD is a complication of oligodendroglioma that may occur preferentially in long surviving patients with 1p/19q co-deletion. LMD in patients with oligodendrogliomas appears to be relatively indolent which may have implications for their treatment and be related to 1p/19q status.

No significant financial relationships to disclose.

Quinolinic acid promotes albumin deposition in Purkinje cell, astrocytic activation and lipid peroxidation in fetal brain

In high concentrations or after prolonged exposure, the N-methyl-D-aspartate receptor agonist quinolinic acid (QUIN) induces lipid peroxidation, oxidative stress, and cell death in the adult brain, and after i.c.v. injection induces seizures and increases blood-brain barrier permeability. As QUIN is substantially increased in plasma and brain of fetal sheep after endotoxin treatment or maternal tryptophan loading, we examined the effects of increasing plasma QUIN concentrations on the brain of late gestation fetal sheep. Continuous fetal infusion of QUIN (0.1 mmol/h i.v.; n=4) for 12 h increased plasma QUIN concentrations from 22.3+/-6.0-210.8+/-31.4 microM; the infusion of vehicle [normal saline] had no effect on QUIN concentrations (n=4). At 24 h after QUIN infusion glial fibrillary acidic protein immunoreactivity was significantly increased in cerebral gray matter and the granule cell layer of cerebellum, and the lipid peroxide product 4-hydroxynonenal-immunoreactivity and albumin-immunoreactivity were present throughout the cytoplasm of cerebellar Purkinje cells. Extravasation of albumin into the brain was not observed, indicating the cerebral microvasculature with respect to permeability to plasma proteins was normal at the time of analysis. We suggest that increased glial fibrillary acidic protein and 4-hydroxynonenal result from oxidative stress induced by QUIN, and that the increased intracellular albumin in cerebellar Purkinje cells may be an adaptive response.

Expression and localization of cyclin-dependent kinase 5 in apoptotic human glioma cells

Cyclin-dependent kinase 5 (Cdk5), a member of the cyclin-dependent kinase family, is expressed predominately in mature neurons and is implicated in neurite extension, neuronal migration, and neuronal differentiation. Cdk5 protein expression also has been associated with apoptosis in a number of nonneuronal model systems. In normal brain, substrates for Cdk5 include neurofilament and tau proteins. Because human tumors of glial origin can express neuronal proteins, we examined whether Cdk5 and its activator protein, P35, are present in early passage human glioblastoma multiforme (GBM) cells lines and primary tumor specimens. Here we report the expression of Cdk5 and an "active" proteolytic form of P35 in human GBM cells and demonstrate kinase activity of the holoenzyme. We also show that Cdk5 kinase activity and expression of its activator protein, P35, is increased in the human GBM cell line M059J after exposure to ionizing radiation and that P35 is localized within M059J cells undergoing apoptosis. These results suggest a possible role for Cdk5 in mediating apoptosis in human GBM cells.