Neuroprotective and Anti-Microglial Activation Effects of Tocotrienols in Brains of Lipopolysaccharide-Induced Inflammatory Model Mice

Inflammation is the cause and/or result of many diseases in peripheral tissues and the central nervous system. Recent findings suggested that inflammation in peripheral tissue induces an inflammatory response in the brain that activates glial cells, which, in turn, induce neuronal cell dysfunction. Therefore, anti-inflammatory compounds are important for the suppression of chronic inflammation and prevention of disease. The present study revealed microglial activation in the hippocampus of the brain two days after the peripheral administration of lipopolysaccharide (LPS). Furthermore, the expression of the synaptic vesicle membrane protein, synaptophysin, in the CA3 stratum lucidum of the hippocampus was down-regulated 7 days after the LPS injection. The administration of tocotrienols, a type of vitamin E, significantly attenuated these changes in the hippocampus. Collectively, the present results demonstrated the spread of peripheral inflammatory responses to the brain, in which glial activation and neuronal dysfunction were induced, while tocotrienols exerted anti-inflammatory effects and protected neurons from damage.

Layer-Specific Vesicular Glutamate Transporter 1 Immunofluorescence Levels Delineate All Layers of the Human Hippocampus Including the Stratum lucidum

The hippocampal formation consists of the Ammon’s horn (cornu Ammonis with its regions CA1-4), dentate gyrus, subiculum, and the entorhinal cortex. The rough extension of the regions CA1-3 is typically defined based on the density and size of the pyramidal neurons without clear-cut boundaries. Here, we propose the vesicular glutamate transporter 1 (VGLUT1) as a molecular marker for the CA3 region. This is based on its strong labeling of the stratum lucidum (SL) in fluorescently stained human hippocampus sections. VGLUT1 puncta of the intense SL band co-localize with synaptoporin (SPO), a protein enriched in mossy fibers (MFs). Owing to its specific intensity profile throughout all hippocampal layers, VGLUT1 could be implemented as a pendant to Nissl-staining in fluorescent approaches with the additional demarcation of the SL. Furthermore, by high-resolution confocal microscopy, we detected VGLUT2 in the human hippocampus, thus reconciling two previous studies. Finally, by VGLUT1/SPO co-staining, we provide evidence for the existence of infrapyramidal MFs in the human hippocampus and we show that SPO expression is not restricted to MF synapses as demonstrated for rodent tissue.

Neurochondrin neurological autoimmunity

ObjectivesTo describe the neurologic spectrum and treatment outcomes for neurochondrin-IgG positive cases identified serologically in the Mayo Clinic Neuroimmunology Laboratory.MethodsArchived serum and CSF specimens previously scored positive for IgGs that stained mouse hippocampal tissue in a nonuniform synaptic pattern by immunofluorescence assay (89 among 616,025 screened, 1993–2019) were reevaluated. Antibody characterization experiments revealed specificity for neurochondrin, confirmed by recombinant protein assays.ResultsIgG in serum (9) or CSF (4) from 8 patients yielded identical neuron-restricted CNS patterns, most pronounced in hippocampus (stratum lucidum in particular), cerebellum (Purkinje cells and molecular layer), and amygdala. All were neurochondrin-IgG positive. Five were women; median symptom onset age was 43 years (range, 30–69). Of 7 with clinical data, 6 presented with rapidly progressive cerebellar ataxia, brainstem signs, or both; 1 had isolated unexplained psychosis 1 year prior. Five of 6 had cerebellar signs, 4 with additional brainstem symptoms or signs (eye movement abnormalities, 3; dysphagia, 2; nausea and vomiting, 1). One patient with brainstem signs (vocal cord paralysis and VII nerve palsy) had accompanying myelopathy (longitudinally extensive abnormality on MRI; aquaporin-4-IgG and myelin oligodendrocyte glycoprotein-IgG negative). The 7th patient had small fiber neuropathy only. Just 1 of 7 had contemporaneous cancer (uterine). Six patients with ataxia or brainstem signs received immunotherapy, but just 1 remained ambulatory. At last follow-up, 5 had MRI evidence of severe cerebellar atrophy.ConclusionIn our series, neurochondrin autoimmunity was usually accompanied by a nonparaneoplastic rapidly progressive rhombencephalitis with poor neurologic outcomes. Other phenotypes and occasional paraneoplastic causes may occur.

The distribution of serotonergic nerve on the hippocampus of the fruit bats (Rousettus amplexicaudatus)

Background: Rousettus amplexicaudatus is one of the old world fruit bats, commonly known in Javanese word as codot belongs to Order Chiroptera and suborder Megachiroptera. R. amplexicaudatus possessed an outstanding visual ability, which helps in the process of searching for food. Those activities process and save within the brain involving the learning and memory activities. Learning and memory activities are centered around the hippocampus with the help of serotonergic nerve. Aim: This study conducted to identify the morphology and distribution of serotonergic nerve (5-hydroxytryptamine) in the hippocampus of R. amplexicaudatus, which related to the function of serotonin within the learning and memory process. Materials and Methods: Five R. amplexicaudatus bats were brought from Gunung Kidul cave, Yogyakarta, Java Island, Indonesia. The bats were anesthetized using ketamine and xylazine. R. amplexicaudatus then perfused intracardially. The brain samples were collected processed into paraffin block, and a further cut in 8 μm thickness serially. The tissue slides were stained using hematoxylin-eosin, cresyl echt violet, and immunohistochemistry with rabbit's anti-serotonin (1:200). The results observed and analyzed quantitatively and qualitatively using image J (https://imagej.nih.gov/ij/) (Bethesda, Maryland, USA) and GraphPad Prism 7 (La Jolla, CA, USA). Results: The hippocampus of R. amplexicaudatus composed of the dentate gyrus (DG), hippocampus proper (cornu ammonis 3 [CA3], and CA1 as the main area for learning memory), and subiculum. On the DG serotonin immunoreactive cells found within the granular layer (132±35.03 cells/mm2), polymorphic stratum (86.33±11.23 cells/mm2), and molecular layer (93±1 cells/mm2). Meanwhile, on CA3 area, the immunoreactive cells for serotonin found in each stratum. The number of immunoreactive cells on each stratum from highest to the lowest are stratum pyramidal 123.33±15.88 cell/mm2, stratum molecular 63±13.11 cell/mm2, stratum lucidum 62.67±8.08 cell/mm2, stratum radiatum 55.33±510.21 cell/mm2, stratum oriens 48±3.46 cell/mm2, and stratum alveus 28.67±2.52 cell/mm2. In addition, in CA1 also hampers the immunoreactive cells in the pyramidal stratum, molecular, lucidum, oriens, radiatum, and alveus layer, respectively, of each 91±27.40 cell/mm2, 60.33±20.65 cell/mm2, 53.67±4.51 cell/mm2 44.33±10.40 cell/mm2, 41.33±5.51 cell/mm2, and 27±4 cell/mm2. Conclusion: Taking together the distribution of serotonin-immunoreactive cells in the hippocampus of R. amplexicaudatus mostly found on CA3 followed by CA 1 and DG.

LTD at mossy fiber synapses onto stratum lucidum interneurons requires TrkB and retrograde endocannabinoid signaling

Hippocampal mossy fiber axons simultaneously activate CA3 pyramidal cells and stratum lucidum interneurons (SLINs), the latter providing feedforward inhibition to control CA3 pyramidal cell excitability. Filopodial extensions of giant boutons of mossy fibers provide excitatory synaptic input to the SLIN. These filopodia undergo extraordinary structural plasticity causally linked to execution of memory tasks, leading us to seek the mechanisms by which activity regulates these synapses. High-frequency stimulation of the mossy fibers induces long-term depression (LTD) of their calcium-permeable AMPA receptor synapses with SLINs; previous work localized the site of induction to be postsynaptic and the site of expression to be presynaptic. Yet, the underlying signaling events and the identity of the retrograde signal are incompletely understood. We used whole cell recordings of SLINs in hippocampal slices from wild-type and mutant mice to explore the mechanisms. Genetic and pharmacologic perturbations revealed a requirement for both the receptor tyrosine kinase TrkB and its agonist, brain-derived neurotrophic factor (BDNF), for induction of LTD. Inclusion of inhibitors of Trk receptor kinase and PLC in the patch pipette prevented LTD. Endocannabinoid receptor antagonists and genetic deletion of the CB1 receptor prevented LTD. We propose a model whereby release of BDNF from mossy fiber filopodia activates TrkB and PLCγ1 signaling postsynaptically within SLINs, triggering synthesis and release of an endocannabinoid that serves as a retrograde signal, culminating in reduced glutamate release. Insights into the signaling pathways by which activity modifies function of these synapses will facilitate an understanding of their contribution to the local circuit and behavioral consequences of hippocampal granule cell activity. NEW & NOTEWORTHY We investigated signaling mechanisms underlying plasticity of the hippocampal mossy fiber filopodial synapse with interneurons in stratum lucidum. High-frequency stimulation of the mossy fibers induces long-term depression of this synapse. Our findings are consistent with a model in which brain-derived neurotrophic factor released from filopodia activates TrkB of a stratum lucidum interneuron; the ensuing activation of PLCγ1 induces synthesis of an endocannabinoid, which provides a retrograde signal leading to reduced release of glutamate presynaptically.

PLEIOTROPIC ENZYMES OF APOPTOSIS AND SYNAPTIC PLASTICITY IN ALBINO RAT HIPPOCAMPUS AFTER OCCLUSION OF COMMON CAROTID ARTERIES

Aim: the aim of the study was to investigate the pleiotropic properties of the apoptotic enzyme caspase-3 and its associations with the synaptic plasticity of the hippocampus of albino rats in healthy animals and in rats after 20-min occlusion of the common carotid arteries.Material and Methods. Total numerical density of neurons, ultrastructure of synapses, and area of immunohistochemically positive hippocampal synaptic terminals of CA1 stratum radiatum and stratum lucidum CA3 were studied by the methods of optical microscopy (hematoxylin and eosin stain), electron microscopy (uranyl acetate and lead citrate as contrast agents), immunohistochemistry (MAP2, synaptophysin, caspase-3, p53, and bcl-2), and morphometry in the brains of intact rats (n=5) and in animals after acute ischemia at day 1 (n=5), 3 (n=5), 7 (n=5), 14 (n=5), and 30 (n=25).Results and Discussion. The study showed that 33.0% of pyramidal neurons in CA1 region and 17.4% of those in CA3 region underwent irreversible damage within 30 days of the post-ischemic period. Among the irreversibly damaged neurons, the cells with signs of coagulative-ischemic necrosis prevailed. In animals subject to ischemia, the relative area of synaptophysin-positive material initially decreased (at day 1) and then recovered (at days 3, 7). We found that caspase-3 colocalized with synaptophysin, which was especially evident in the giant synapses of the stratum lucidum of the hippocampal CA3 region. In the neurosomes of the hippocampal pyramidal cells, caspase-3 was not detected. However, this enzyme was found in the terminals of the axo-dendritic, axo-spine, and axo-somatic synapses. In the course of th e post-ischemic period, the most pronounced changes in the expression of caspase-3 were observed in the stratum radiatum of the CA1 field. Apoptosis regulatory proteins (p53, bcl-2) were detected in the individual neurons. In this regard, caspase-3 should be viewed in the context of its pleiotropy and involvement in the adaptation and recovery processes due to post-ischemic activation of neuroplasticity at the level of axons and synapses.Conclusion. After acute ischemia caused by 20-min occlusion of the common carotid arteries, the activation of caspase-3 contributes to ischemic preconditioning and neuroprotection.

Neurons Communication in the Hippocampus of Field CA3 of the White Rat Brain after Acute ischemia

The aim of this studywas to compare the pyramidal neurons, their processes and synapses in the stratum lucidum, stratum radiatum and stratum lacunosum of the molecular layer of the field CA3 of the hippocampus of the brain of white rats in the normal state and after acute ischemia caused by a 20-minute occlusion of the common carotid arteries.Materials and methods.In the experiment, using histological methods (hematoxylin and eosin, staining by Nissle and immunohistochemistry for p38, MAP-2) and electron microscopy, the pyramidal neurons of field CA3, their processes and synapses in stratum lucidum, stratum radiatum and stratum lacunosum of the molecular layer were studied. The main group included animals in the reperfusion period (1, 3, 7, 14, 21, and 30 days;n=30), comparison group — falsely operated animals (n=20). Morphometric analysis was performed using ImageJ 1.46, the verification of statistical hypotheses — Statistica 8.0.Results.After occlusion of the common carotid arteries (CCAO) in the field CA3 of hippocampus, reactive, compensatory and reparative reorganization of pyramidal neurons and their communication structures was noted. On day 1, there was a decrease, and then (days 3—14) restoration of the total number of synapses and of P38-positive material within the area of synapses. According to electron microscopy, in the early post-ischemic period, the total numerical density of synaptic contacts in the stratum lacunosum of the molecular layer decreased by 44.8%, and after 14 days recovered to control. In stratum lucidum, the area of P38-positive material decreased by 8.8% after 1 day, and recovered after 3—7 days.Conclusion.After the CCAO, the communication systems of the pyramid neurons of the field CA3 hippocampus of white rats were reorganized. Neurons of the field CA3 had high tolerance to ischemia and ability to restore interneural relations after reperfusion. In the surviving neurons, high levels of the cytoskeleton (MAP-2) marker and synaptic vesicles (p38) were detected. Data demonstrate structural and functional safety of all components of the communication system of a significant part of pyramidal neurons in acute ischemia. After reperfusion, the most significant alterations included the reconstructed interneuron synapses in the stratum radiatum and the lacunosum molecular layer.

MORPHOLOGICAL CHARACTERISTICS OF EPIDERMIS AND DERMIS IN PATIENTS WITH DIFFUSE ALOPECIA, ANDROGENETIC ALOPECIA AND ALOPECIA AREATA

Despite the emergence of non-invasive and very informative techniques, such as trichoscopy and confocal microscopy, it is still necessary to use a skin biopsy of the scalp. Currently, there is a lot of information about hystopathology of the scalp in patients with diffuse alopecia, androgenetic alopecia and alopecia areata [1]. Researches mostly aim to study the follicular unit, whereas data on pathological changes in the epidermis, papillary and reticular dermis in the above-mentioned alopecia are rare and scattered. In this connection, the aim of the research was to study morphological characteristics of epidermis and dermis in patients with diffuse alopecia, androgenetic alopecia and alopecia areata. Material and methods. We examined 25 patients (12 women and 13 men) aged 17 to 60 years with not cicatricial alopecia: androgenetic alopecia was observed in 10 patients, alopecia areata - in 9 patients, diffuse alopecia - in 6 patients. The age of the disease ranged from 1 month to 5 years. The control group consisted of 9 people. The review microscopy and morphometry of samples, taken for investigation, were performed using the eyepiece micrometer MOB-1-15xУ4.2. The following indicators in the dermis were evaluated: the presence of lymphohistiocytic infiltrates in the papillary and reticular dermis, mucoid swelling of sclerosis of the papillary dermis, and signs of destruction of hair follicles. Results. The tendency to increase thickness of the epidermis in patients with diffuse alopecia is associated with thickening of the stratum granulosum and especially the stratum corneum. In case of androgenetic alopecia and alopecia areata the tendency to decrease the thickness of the epidermis is associated with a tendency to reduce the thickness of the stratum lucidum. Regardless of the type of alopecia, the thickness of the stratum basale is statistically higher than in the control group. Regardless of the type of alopecia, changes in the dermis are manifested by the destruction of hair follicles followed by the presence of lymphohistiocytic infiltrates in the papillary and reticular dermis, as well as sclerosis of the papillary dermis. Discussion. It can be anticipated that the presence of lymphohistiocytic infiltrates in the papillary and reticular dermis may indicate the inflammatory process, which is accompanied by abnormal microcirculation and the destruction of the hair follicle which in turn insufficiently stimulates angiogenesis.

The neuropathological study of myelin oligodendrocyte glycoprotein in the temporal lobe of schizophrenia patients

ObjectiveRecent studies based on the neuroimaging analysis, genomic analysis and transcriptome analysis of the postmortem brain suggest that the pathogenesis of schizophrenia is related to myelin-oligodendrocyte abnormalities. However, no serious neuropathological investigation of this protein in the schizophrenic brain has yet been performed. In this study, to confirm the change in neuropathological findings due to the pathogenesis of this disease, we observed the expression of myelin-oligodendrocyte directly in the brain tissue of schizophrenia patients.MethodsMyelin oligodendrocyte glycoprotein (MOG) was evaluated in the cortex of the superior temporal gyrus (STG) and the hippocampus in 10 schizophrenic and nine age- and sex-matched normal control postmortem brains.ResultsThe expression of MOG was significantly lower in the middle layer of the neocortex of the STG and stratum lucidum of CA3 in the hippocampus in the long-term schizophrenic brains (patients with ≥30 years of illness duration) than in the age-matched controls. Furthermore, the thickness of MOG-positive fibre-like structures was significantly lower in both regions of the long-term schizophrenic brains than in the age-matched controls.ConclusionThese findings suggest that a long duration of illness has a marked effect on the expression of MOG in these regions, and that myelin-oligodendrocyte abnormalities in these regions may be related to the progressive pathophysiology of schizophrenia.