Transformation of an odontogenic keratocyst into a solid variant of odontogenic keratocyst/keratoameloblastoma during long‑term follow‑up: A case report

Keratoameloblastoma (KA) and solid variant of odontogenic keratocyst (SOKC) are rare odontogenic lesions, and their relationship and differences are unclear. The present study described a case that started as an odontogenic keratocyst (OKC) and transformed to SOKC/KA upon recurrence. Briefly, a 26‑year‑old man presented with swelling in the right cheek and was referred to the Department of Oral and Maxillofacial surgery, Hiroshima University Hospital (Hiroshima, Japan). At the initial visit, unicystic bone permeation was observed extending from the right canine to the molar, maxillary sinus and nasal cavity. After the biopsy, the patient underwent excisional surgery and was diagnosed with OKC. Thereafter, the lesion recurred six times over a period of 13 years and showed different histopathological features from those of the primary lesion, all consisting of numerous cysts with keratinization, which were diagnosed as SOKC/KA. The Ki‑67 positivity rate was ~10%, which was higher than that of the primary lesion, but there was no atypia. Genetic analysis of the recurrent lesion revealed mutations in adenomatous polyposis coli and Kirsten rat sarcoma viral oncogene homolog. This case originated from OKC, and the morphological features of OKC and KA were mixed upon recurrence, supporting the commonality and association between the two. However, multiple mutations different from those of OKC and ameloblastoma were detected, suggesting an association of SOKC/KA with increased proliferative activity and a high recurrence rate.

The Impact of Posterior Corneal Astigmatism on Surgically Induced Astigmatism in Cataract Surgery

PURPOSE

This study aimed to evaluate the changes in posterior corneal astigmatism after cataract surgery and provide a theoretical basis to accurately evaluate the total corneal astigmatism (TA) to be corrected before toric intraocular lens (IOL) implantation.

PATIENTS AND METHODS

Sixty-two patients (89 eyes) who underwent phacoemulsification combined with toric IOL implantation (AcrySof IQ Toric SN6AT2-T9) at Shanxi Eye Hospital between January 2017 and September 2018 were enrolled. Surgically induced astigmatism of the posterior cornea (SIAPA) was analysed using vector analysis during pentacam examination.

RESULTS

The vector variances of keratometric astigmatism (KA), TA, and posterior corneal astigmatism (PA) preoperatively and postoperatively in the "with-the-rule (WTR) astigmatism" group and "overall patient" group were statistically significant (P < 0.05). A statistically significant difference was observed between surgically induced KA (SIAKA) and surgically induced astigmatism of the total cornea (SIATA) for all patients, including those with WTR astigmatism. For all patients, SIAKA was less than SIATA by 0.05 ± 0.21 D, and for patients with WTR astigmatism, SIAKA was less than SIATA by 0.09 ± 0.22 D. For patients in the "against-the-rule (ATR) astigmatism" group, there were no statistically significant differences between SIAKA and SIATA, although SIAKA was greater than SIATA by 0.03 ± 0.18 D. When PA ≤0.4 D or KA ≤2.0 D, SIAPA can be ignored. However, when PA >0.4 D or KA >2.0 D, ignoring SIAPA caused by cataract surgery incision will cause SIAKA in patients with WTR astigmatism to underestimate SIATA, while SIAKA in patients with ATR astigmatism will cause an overestimation of SIATA.

CONCLUSION

SIA on the posterior corneal astigmatism may have a significant role on more precise planning of toric IOL implantation, especially in cases with higher preoperative anterior or posterior corneal astigmatism.

No Significant Differences in Clinical and Radiographic Outcomes between PCL Retained or Sacrificed Kinematic Aligned Medial Pivot Total Knee Arthroplasty in Varus Knee

In the last decades, several surgical techniques, such as medial pivot (MP) philosophy and kinematic alignment (KA), have been introduced in total knee arthroplasty (TKA) to improve patients’ outcomes. This retrospective study aims to evaluate the clinical, radiographic, and functional results of PCL preservation or sacrifice in KA MP-TKA. A consecutive series of 147 patients older than 60, with a minimum follow-up of two years, were treated with TKA for severe primary knee osteoarthritis (OA) at the Department of Orthopedics and Traumatology between 1 January 2019, and 1 July 2020. After excluding those not meeting the inclusion criteria, 64 patients were included in the study analysis. Regarding radiographic outcomes, no statistically significant difference was observed between patients with preserved or sacrificed PCL (p > 0.05). A slight improvement in Knee Society Score (KSS), knee and function score, and FJS was observed for the PCL-preserved group, although this superiority tendency was not statistically significant (p > 0.05). PCL-preserved MA MP-TKA reported a statistically significant result in only two questions on the FJS questionnaire (p < 0.05). A slight, non-statistically significant improvement in active ROM was found in the PCL-sacrificed group (p > 0.05). No interventions or revisions were reported in this case series for all treated patients at the final follow-up. No significant differences were described in clinical, radiographic, and functional outcomes in preserved or sacrificed PCL KA MP-TKA. Although not significant, a slight trend toward better clinical outcomes was reported in PCL-preserved KA MP-TKA.

Restricted kinematic alignment in primary total knee arthroplasty: A systematic review of radiographic and clinical data

Introduction

Kinematic alignment (KA) has increased in popularity in recent years, becoming a viable alternative to MA with encouraging short- and mid-term follow-up results. Recently, the concept of restricted kinematic alignment (rKA) has been developed to restore native knee kinematics better, avoiding failure of coronal alignment. This systematic review aims to examine whether rKA improves outcome scores (PROMs) compared with MA and to evaluate the radiographic analysis of the lower limb alignment and the causes of complications and reoperations with the rKA approach.

Methods

A systematic literature search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines on the Pubmed/Medline, Scopus, Cochrane Library, and Embase databases. The following key terms were used: "restricted kinematic alignment, rKA, kinematic alignment, primary total knee arthroplasty, primary total knee replacement, TKA rKA, and TKR rKA." The initial screening identified 328 studies. Each eligible article was evaluated according to the inclusion criteria: studies with levels of evidence (LoE) 1 to 4, written in English, published through May 2022, and involving human subjects. Criteria from the Methodological Index for Non-Randomized Studies (MINORS) were used to assess the methodological quality of the articles.

Results

Six clinical studies were included in this systematic review. The study was registered in the International Prospective Registry of Systematic Reviews (PROSPERO). A total of 574 knees were included. After excluding patients due to loss of follow-up or missing data, 475 knees were analyzed. The following rKA-related data were evaluated: patient-reported outcome scores (PROMs), radiographic analysis of the lower limb alignment, and causes of complications and reoperations.

Conclusions

The rKA is an improved concept for restoring native knee kinematics, avoiding excessive coronal varus/valgus alignment. It provides equivalent or slightly better PROMs than MA without increasing the risk of short-middle-term implant failure. Clinical studies with extended follow-up are needed to confirm this trend.

H19 silencing decreases kainic acid-induced hippocampus neuron injury via activating the PI3K/AKT pathway via the H19/miR-206 axis

Temporal lobe epilepsy (TLE) is the most common type of intractable epilepsy and is refractory to medications. However, the role and mechanism of H19 in regulating TLE remains largely undefined. Expression of H19 and miR-206 was detected using real-time quantitative PCR (RT-qPCR). Cell apoptosis, autophagy and inflammatory response were determined by flow cytometry, western blotting and enzyme-linked immunosorbent assay (ELISA). The interaction between H19 and miR-206 was predicted on the miRcode database and confirmed by luciferase reporter assay, RNA immunoprecipitation (RIP) and RNA pull-down. H19 was upregulated and miR-206 was downregulated in the rat hippocampus neurons after kainic acid (KA) treatment. Functionally, both H19 knockdown and miR-206 overexpression weakened KA-induced apoptosis, autophagy, inflammatory response, and oxidative stress in hippocampus neurons. Mechanically, the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway was activated by H19 knockdown and miR-206 was confirmed to be targeted and negatively regulated by H19. Moreover, downregulation of miR-206 could counteract the effects of H19 knockdown in KA-induced hippocampus neurons. Knockdown of H19 suppressed hippocampus neuronal apoptosis, autophagy and inflammatory response presumably through directly upregulating miR-206 and activating the PI3K/AKT signaling pathway.

Deleterious Effect of NMDA Plus Kainate on the Inner Retinal Cells and Ganglion Cell Projection of the Mouse

Combined administration of N-Methyl-D-Aspartate (NMDA) and kainic acid (KA) on the inner retina was studied as a model of excitotoxicity. The right eye of C57BL6J mice was injected with 1 µL of PBS containing NMDA 30 mM and KA 10 mM. Only PBS was injected in the left eye. One week after intraocular injection, electroretinogram recordings and immunohistochemistry were performed on both eyes. Retinal ganglion cell (RGC) projections were studied by fluorescent-cholerotoxin anterograde labeling. A clear decrease of the retinal "b" wave amplitude, both in scotopic and photopic conditions, was observed in the eyes injected with NMDA/KA. No significant effect on the "a" wave amplitude was observed, indicating the preservation of photoreceptors. Immunocytochemical labeling showed no effects on the outer nuclear layer, but a significant thinning on the inner retinal layers, thus indicating that NMDA and KA induce a deleterious effect on bipolar, amacrine and ganglion cells. Anterograde tracing of the visual pathway after NMDA and KA injection showed the absence of RGC projections to the contralateral superior colliculus and lateral geniculate nucleus. We conclude that glutamate receptor agonists, NMDA and KA, induce a deleterious effect of the inner retina when injected together into the vitreous chamber.

NADPH protects against kainic acid-induced excitotoxicity via autophagy-lysosome pathway in rat striatum and primary cortical neurons

PURPOSE

To investigate the effects and mechanisms of NADPH on Kainic acid (KA)-induced excitotoxicity.

METHODS

KA, a non-N-methyl-d-aspartate glutamate receptor agonist, was exposed to adult SD rats via intrastriatal injection and rat primary cortical neurons to establish excitotoxic models in vivo and in vitro, respectively. To determine the effects of NADPH on KA-induced excitotoxicity, neuronal survival, neurologically behavioral score and oxidative stress were evaluated. To explore the mechanisms of neuroprotective effects of NADPH, the autophagy-lysosome pathway related proteins were detected.

RESULTS

In vivo, NADPH (1 mg/kg or 2 mg/kg) diminished KA (2.5 nmol)-induced enlargement of lesion size in striatum, improved KA-induced dyskinesia and reversed KA-induced activation of glial cells. Nevertheless, the neuroprotective effect of NADPH was not significant under the condition of autophagy activation. NADPH (2 mg/kg) inhibited KA (2.5 nmol)-induced down-regulation of TP-53 induced glycolysis and apoptosis regulator (TIGAR) and p62, and up-regulation of the protein levels of LC3-II/LC3-I, Beclin-1 and Atg5. In vitro, the excitotoxic neuronal injury was induced after KA (50 μM, 100 μM or 200 μM) treatment as demonstrated by decreased cell viability. Moreover, KA (100 μM) increased the intracellular levels of calcium and reactive oxygen species (ROS) and declined the levels of the reduced form of glutathione (GSH). Pretreatment of NADPH (10 μM) effectively reversed these changes. Meanwhile NADPH (10 μM) inhibited KA (100 μM)-induced down-regulation of TIGAR and p62, and up-regulation of the ratio of LC3-II/LC3-I, Beclin-1, Atg5, active-cathepsin B and active-cathepsin D.

CONCLUSIONS

Our data provide a possible mechanism that NADPH ameliorates KA-induced excitotoxicity by blocking the autophagy-lysosome pathway and up-regulating TIGAR along with its antioxidant properties.

Anti-Inflammatory Mechanisms of Koreanaside A, a Lignan Isolated from the Flower of Forsythia koreana, against LPS-Induced Macrophage Activation and DSS-Induced Colitis Mice: The Crucial Role of AP-1, NF-κB, and JAK/STAT Signaling

The current treatment options for inflammatory bowel disease (IBD) are unsatisfactory. Therefore, novel and safer therapies are needed. We previously reported that koreanaside A (KA) showed high radical scavenging activity and suppressed vascular cell adhesion molecule 1 (VCAM-1) expression in vascular smooth muscle cells. However, the molecular mechanisms involved in its anti-inflammatory effect have not been reported. KA inhibited pro-inflammatory mediators such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nitric oxide (NO), and prostaglandin E₂ (PGE₂). KA inhibited the production and mRNA expression of interleukin (IL)-6 and tumor necrosis factor-α (TNF-α) induced by LPS. KA downregulated the myeloid differentiation primary response 88 (MyD88)-dependent inflammatory gene expressions in the MyD88-overexpressed cells. KA suppressed the LPS-induced transcriptional and DNA-binding activities of activator protein-1 (AP-1) and nuclear factor-kappa B (NF-κB). KA was found to inhibit the phosphorylation of Janus kinase 1/2 (JAK1/2) and signal transducers and activators of transcription 1/3 (STAT1/3). In DSS-induced colitis mice, KA relieved the symptoms of colitis by suppressing inflammatory cell infiltration, restoring tight junction (TJ)- and epithelial–mesenchymal transition (EMT)-related protein expression, and inactivating AP-1, NF-κB, and STAT1/3. Therefore, KA reduced inflammatory responses by downregulating AP-1, NF-κB, and JAK/STAT signaling in LPS-induced macrophages and DSS-induced colitis mice.

Long-term neurotoxic effects of domoic acid on primary dopaminergic neurons

Domoic acid, an excitatory neurotoxin produced by certain algae, reaches the food chain through accumulation in some sea organisms. To investigate its long-term neurotoxicity on dopaminergic neurons, prepared primary mesencephalic cell cultures were exposed to different concentrations of domoic acid (0.1, 1, 10, 100 μM) on the 8th day in vitro (DIV) for 4 days. On the 12th DIV, culture media were collected for measurement of lactate dehydrogenase and cultured cells were subjected to immunohistochemistry against tyrosine hydroxylase, neuronal nuclear antigen and glial fibrillary acidic protein, and fluorescence staining using H₂DCFDA, JC-1 and Hoechst 33342 dyes. Moreover, roles of AMPA/KA and NMDA receptors in domoic acid neurotoxicity were also investigated. Domoic acid significantly decreased the number of dopaminergic neurons and adversely affected their morphology, and slightly reduced the expression of neuronal nuclear antigen and glial fibrillary acidic protein. Co-treatment of cultures with domoic acid and the AMPA/KA or NMDA receptor antagonists NBQX and MK-801 rescued significant number of dopaminergic neurons. Domoic acid significantly decreased red:green fluorescence ratio of JC-1 and did not affect production of reactive oxygen species and apoptotic cell death. In conclusions, the present study reveals that long-term treatment of primary mesencephalic cell culture with domoic acid significantly destroyed dopaminergic neurons. This effect appears to be attributed to activation of AMPA/KA and NMDA receptors and mitochondrial damage.

Socio-demographic and Psychological Correlates of Posttraumatic Growth among Korean Americans with a History of Traumatic Life Experiences

This study examined socio-demographic and psychological correlates of posttraumatic growth (PTG) among Korean Americans (KAs) with traumatic life experiences. A total of 286 KAs were included. Being a woman or having a lower annual household income had positive associations with PTG, while having no religion had a negative association with it. In addition, praying and visiting a mental health professional for coping with stress or for psychological problems was positively associated with PTG. Higher resilience scores increased PTG, while depressive symptoms decreased it. We suggest reinforcing help seeking behaviors and accessibility to care facilities, and gender specific strengthening programs for enhancing PTG among KAs.

A clinical, histopathological and immunohistochemical approach to the bewildering diagnosis of keratoacanthoma

Keratoacanthoma (KA) is a comparatively common low-grade tumor that initiates in the pilo-sebaceous glands and pathologically mimics squamous cell carcinoma (SCC). Essentially, strong debates confirm classifying keratoacanthoma as a variant of invasive SCC. The clinical behavior of KA is hardly predictable and the differential diagnosis of keratoacanthoma and other conditions with keratoacanthoma-like pseudocarcinomatous epithelial hyperplasia is challenging, both clinically and histopathologically. This article aims to illustrate and explicate some of these complicated issues by presenting two cases of KA and a relevant review of literature. It also targets the clinical, histopathologic, and immuno-histochemical features of these two cases. Both presented lesions of this study had appeared on the vermilion border of the lower lip and no vascular or perineural invasion was observed. The results of the immuno-histochemical survey, particularly in staining with marker CD30, confirmed the differential diagnosis of keratoacanthoma from keratoacanthoma-like pseudocarcinomatous proliferations which was consequent to the CD30(+) lymphoid infiltration. Histopathological and immunohistochemical investigation is necessary to disprove the invasive biologic behavior of keratoacanthoma and also to refute all conditions with keratoacanthoma-like pseudocarcinomatous epithelial hyperplasia.

Treatment with melatonin after status epilepticus attenuates seizure activity and neuronal damage but does not prevent the disturbance in diurnal rhythms and behavioral alterations in spontaneously hypertensive rats in kainate model of temporal lobe epilepsy

Melatonin is involved in the control of circadian and seasonal rhythmicity, possesses potent antioxidant activity, and exerts a neuroprotective and anticonvulsant effect. Spontaneously hypertensive rats (SHRs) are widely accepted as an experimental model of essential hypertension with hyperactivity, deficient sustained attention, and alterations in circadian autonomic profiles. The purpose of the present study was to determine whether melatonin treatment during epileptogenesis can prevent the deleterious consequences of status epilepticus (SE) in SHRs in the kainate (KA) model of temporal lobe of epilepsy (TLE). Spontaneous recurrent seizures (SRSs) were EEG- and video-recorded during and after the treatment protocol. Melatonin (10mg/kg diluted in drinking water, 8weeks) increased the seizure-latent period, decreased the frequency of SRSs, and attenuated the circadian rhythm of seizure activity in SHRs. However, melatonin was unable to affect the disturbed diurnal rhythms and behavioral changes associated with epilepsy, including the decreased anxiety level, depression, and impaired spatial memory. Melatonin reduced neuronal damage specifically in the CA1 area of the hippocampus and piriform cortex and decreased hippocampal serotonin (5-HT) levels both in control and epileptic SHRs. Although long-term melatonin treatment after SE shows a potential to attenuate seizure activity and neuronal loss, it is unable to restore epilepsy-associated behavioral abnormalities in SHRs.

A quantitative MRI study

The blood-brain barrier (BBB) plays an important role in the homeostasis of the brain. BBB dysfunction has been implicated in the pathophysiology of various neurological disorders, including epilepsy in which it may contribute to disease progression. Precise understanding of BBB dynamics during epileptogenesis may be of importance for the assessment of future therapies, including BBB leakage blocking-agents. Longitudinal changes in BBB integrity can be studied with in vivo magnetic resonance imaging (MRI) in combination with paramagnetic contrast agents. Although this approach has shown to be suitable to detect major BBB leakage during the acute phase in experimental epilepsy models, so far no studies have provided information on dynamics of the extent of BBB leakage towards later phases. Therefore a sensitive and quantitative approach was used in the present study, involving fast T1 mapping (dynamic approach) during a steady-state infusion of gadobutrol, as well as pre- and post-contrast T1-weighted MRI (post-pre approach). This was applied in an experimental epilepsy model in which previous MRI studies failed to detect BBB leakage during epileptogenesis. Adult male Sprague-Dawley rats were injected with kainic acid to induce status epilepticus (SE). MRI experiments were performed before SE (control) and during the acute (1 day) and chronic epileptic phases (6 weeks after SE). BBB leakage was quantified by fast T1 mapping (Look-Locker gradient echo MRI) with a time resolution of 48 s from 5 min before up to 45 min after 20 min step-down infusion of 0.2M gadobutrol. In addition, T1-weighted MRI was acquired before and 45 min after infusion. MRI data were compared to post-mortem microscopic analysis using the BBB tracer fluorescein. Our MRI data showed BBB leakage, which was evident at 1 day and 6 weeks after SE in the hippocampus, entorhinal cortex, amygdala and piriform cortex. These findings were confirmed by microscopic analysis of fluorescein leakage. Furthermore, our MRI data revealed non-uniform BBB leakage throughout epileptogenesis. This study demonstrates BBB leakage in specific brain regions during epileptogenesis, which can be quantified using MRI. Therefore, MRI may be a valuable tool for experimental or clinical studies to elucidate the role of the BBB in epileptogenesis.

Targeting deficiencies in mitochondrial respiratory complex I and functional uncoupling exerts anti-seizure effects in a genetic model of temporal lobe epilepsy and in a model of acute temporal lobe seizures

Mitochondria actively participate in neurotransmission by providing energy (ATP) and maintaining normative concentrations of reactive oxygen species (ROS) in both presynaptic and postsynaptic elements. In human and animal epilepsies, ATP-producing respiratory rates driven by mitochondrial respiratory complex (MRC) I are reduced, antioxidant systems are attenuated and oxidative damage is increased. We report that MRCI-driven respiration and functional uncoupling (an inducible antioxidant mechanism) are reduced and levels of H2O2 are elevated in mitochondria isolated from KO mice. Experimental impairment of MRCI in WT hippocampal slices via rotenone reduces paired-pulse ratios (PPRs) at mossy fiber-CA3 synapses (resembling KO PPRs), and exacerbates seizure-like events in vitro. Daily treatment with AATP [a combination therapy composed of ascorbic acid (AA), alpha-tocopherol (T), sodium pyruvate (P) designed to synergistically target mitochondrial impairments] improved mitochondrial functions, mossy fiber PPRs, and reduced seizure burden index (SBI) scores and seizure incidence in KO mice. AATP pretreatment reduced severity of KA-induced seizures resulting in 100% protection from the severe tonic-clonic seizures in WT mice. These data suggest that restoration of bioenergetic homeostasis in the brain may represent a viable anti-seizure target for temporal lobe epilepsy.

High-frequency stimulation of the hippocampus protects against seizure activity and hippocampal neuronal apoptosis induced by kainic acid administration in macaques

Kainic acid (KA) administration is known to cause seizures and neuronal death in the hippocampus. High-frequency stimulation (HFS) of the hippocampus can be a promising method in the treatment of epilepsy while the mechanism of action is unknown yet. It remains unknown whether HFS is neuroprotective for hippocampal neurons following KA-induced seizures in macaques, although HFS has neuroprotective effects in animal models of Parkinson's disease. We therefore examined the effects of HFS on KA-induced seizures and neuronal survival in macaque's hippocampus. Seizure frequency following KA that led to seizures in macaques was strongly reduced by HFS of the hippocampus. In addition, administration of KA led to marked neuronal apoptosis in the hippocampus, accompanied by increased levels of Bax, activated caspase-3 and decreased levels of Bcl-2. HFS was found to attenuate changes in apoptosis-related proteins and robustly decreased neuronal loss following KA administration. These data indicate that hippocampal HFS can protect hippocampal neurons against KA neurotoxicity, and that HFS neuroprotection is likely to operate with inhibition of apoptosis.

Seizure-induced disinhibition of the HPA axis increases seizure susceptibility

Stress is the most commonly reported precipitating factor for seizures. The proconvulsant actions of stress hormones are thought to mediate the effects of stress on seizure susceptibility. Interestingly, epileptic patients have increased basal levels of stress hormones, including corticotropin-releasing hormone (CRH) and corticosterone, which are further increased following seizures. Given the proconvulsant actions of stress hormones, we proposed that seizure-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis may contribute to future seizure susceptibility. Consistent with this hypothesis, our data demonstrate that pharmacological induction of seizures in mice with kainic acid or pilocarpine increases circulating levels of the stress hormone, corticosterone, and exogenous corticosterone administration is sufficient to increase seizure susceptibility. However, the mechanism(s) whereby seizures activate the HPA axis remain unknown. Here we demonstrate that seizure-induced activation of the HPA axis involves compromised GABAergic control of CRH neurons, which govern HPA axis function. Following seizure activity, there is a collapse of the chloride gradient due to changes in NKCC1 and KCC2 expression, resulting in reduced amplitude of sIPSPs and even depolarizing effects of GABA on CRH neurons. Seizure-induced activation of the HPA axis results in future seizure susceptibility which can be blocked by treatment with an NKCC1 inhibitor, bumetanide, or blocking the CRH signaling with Antalarmin. These data suggest that compromised GABAergic control of CRH neurons following an initial seizure event may cause hyperexcitability of the HPA axis and increase future seizure susceptibility.

Peripheral immunomodulation with ginsenoside Rg1 ameliorates neuroinflammation-induced behavioral deficits in rats

Neuroinflammatory disturbances have been closely associated with depression and many other neuropsychiatric diseases. Although targeting neuroinflammatory mediators with centrally acting drugs has shown certain promise, its translation is faced with several challenges especially drug delivery and safety concerns. Here, we report that neuroinflammation-induced behavioral abnormality could be effectively attenuated with immunomodulatory agents that need not to gain brain penetration. In a rat model with intracerebral lipopolysaccharide (LPS) challenge, we validated that ginsenoside Rg1 (Rg1), a well-established anti-inflammatory agent, was unable to produce a direct action in the brain. Interestingly, peripherally restricted Rg1 could effectively attenuate the weight loss, anorexic- and depressive-like behavior as well as neurochemical disturbances associated with central LPS challenge. Biochemical assay of neuroimmune mediators in the periphery revealed that Rg1 could mitigate the deregulation of the hypothalamic-pituitary-adrenal axis and selectively blunt the increase in circulating interleukin-6 levels. Furthermore, these peripheral regulatory effects were accompanied by dampened microglial activation, mitigated expression of pro-inflammatory mediators and neurotoxic species in the central compartment. Taken together, our work suggested that targeting the peripheral immune system may serve as a novel therapeutic approach to neuroinflammation-induced neuropsychiatric disorders. Moreover, our findings provided the rationale for employing peripherally active agents like Rg1 to combat mental disturbances.

Role of the ubiquitin-proteasome system in brain ischemia: friend or foe?

The ubiquitin-proteasome system (UPS) is a catalytic machinery that targets numerous cellular proteins for degradation, thus being essential to control a wide range of basic cellular processes and cell survival. Degradation of intracellular proteins via the UPS is a tightly regulated process initiated by tagging a target protein with a specific ubiquitin chain. Neurons are particularly vulnerable to any change in protein composition, and therefore the UPS is a key regulator of neuronal physiology. Alterations in UPS activity may induce pathological responses, ultimately leading to neuronal cell death. Brain ischemia triggers a complex series of biochemical and molecular mechanisms, such as an inflammatory response, an exacerbated production of misfolded and oxidized proteins, due to oxidative stress, and the breakdown of cellular integrity mainly mediated by excitotoxic glutamatergic signaling. Brain ischemia also damages protein degradation pathways which, together with the overproduction of damaged proteins and consequent upregulation of ubiquitin-conjugated proteins, contribute to the accumulation of ubiquitin-containing proteinaceous deposits. Despite recent advances, the factors leading to deposition of such aggregates after cerebral ischemic injury remain poorly understood. This review discusses the current knowledge on the role of the UPS in brain function and the molecular mechanisms contributing to UPS dysfunction in brain ischemia with consequent accumulation of ubiquitin-containing proteins. Chemical inhibitors of the proteasome and small molecule inhibitors of deubiquitinating enzymes, which promote the degradation of proteins by the proteasome, were both shown to provide neuroprotection in brain ischemia, and this apparent contradiction is also discussed in this review.

Heat shock protein 70 protects against seizure-induced neuronal cell death in the hippocampus following experimental status epilepticus via inhibition of nuclear factor-κB activation-induced nitric oxide synthase II expression

Status epilepticus induces subcellular changes that may eventually lead to neuronal cell death in the hippocampus. Based on an animal model of status epilepticus, our laboratory showed previously that sustained hippocampal seizure activity activates nuclear factor-κB (NF-κB) and upregulates nitric oxide synthase (NOS) II gene expression, leading to apoptotic neuronal cell death in the hippocampus. The present study examined the potential modulatory role of heat shock protein 70 (HSP70) on NF-κB signaling in the hippocampus following experimental status epilepticus. In Sprague-Dawley rats, kainic acid (KA) was microinjected unilaterally into the hippocampal CA3 subfield to induce prolonged bilateral seizure activity. Expression of HSP70 was elevated as early as 1h after the elicitation of sustained seizure activity, followed by a progressive elevation that peaked at 24h. Pretreatment with an antisense oligonucleotide against hsp70 decreased the HSP70 expression, and significantly augmented IκB kinase (IKK) activity and phosphorylation of IκBα, alongside enhanced nuclear translocation and DNA binding activity of NF-κB in the hippocampal CA3 neurons and glial cells. These cellular events were followed by enhanced upregulation of NOS II and peroxynitrite expression 3h after sustained seizure activity that led to an increase of caspase-3 and DNA fragmentation in the hippocampal CA3 neurons 7days after experimental status epilepticus. We concluded that HSP70 protects against apoptotic cell death induced by NF-κB activation and NOS II-peroxynitrite signaling cascade in the hippocampal CA3 and glial cells following experimental status epilepticus via suppression of IKK activity and deactivation of IκBα.

Maturation-dependent behavioral deficits and cell injury in developing animals during the subacute postictal period

Prolonged early-life seizures are associated with disruptions of affective and cognitive function. Postictal disturbances, temporary functional deficits that persist for hours to days after seizures, have not yet been thoroughly characterized. Here, we used kainic acid (KA) to induce status epilepticus (SE) in immature rats at three developmental stages (postnatal day (P) 15, 21, or 30) and subsequently assessed spatial learning and memory in a Barnes maze, exploratory behavior in an open field, and the spatiotemporal distribution of cell injury during the first 7-10 days of the postictal period. At 1 day post-SE, P15-SE rats showed no deficit in the Barnes maze but were hyperexploratory in an open field compared with their littermate controls. In contrast, P21- and P30-SE rats exhibited markedly impaired performance in the Barnes maze and exhibited significantly reduced open field exploration suggestive of anxiety-like behavior. These behavioral changes were transient in P15 rats but more persistent in P21 and enduring in P30 rats after KA-SE. The time course of behavioral deficits in P21 and P30 rats was temporally correlated with the presence of neuronal injury in the lateral septal nuclei, amygdala, and ventral subiculum/CA1, regions involved in modulation of the hypothalamic-pituitary-adrenal stress response.

Electrographic seizures are significantly reduced by in vivo inhibition of neuronal uptake of extracellular glutamine in rat hippocampus

Rats were given unilateral kainate injection into hippocampal CA3 region, and the effect of chronic electrographic seizures on extracellular glutamine (GLNECF) was examined in those with low and steady levels of extracellular glutamate (GLUECF). GLNECF, collected by microdialysis in awake rats for 5h, decreased to 62±4.4% of the initial concentration (n=6). This change correlated with the frequency and magnitude of seizure activity, and occurred in the ipsilateral but not in contralateral hippocampus, nor in kainate-injected rats that did not undergo seizure (n=6). Hippocampal intracellular GLN did not differ between the Seizure and No-Seizure Groups. These results suggested an intriguing possibility that seizure-induced decrease of GLNECF reflects not decreased GLN efflux into the extracellular fluid, but increased uptake into neurons. To examine this possibility, neuronal uptake of GLNECF was inhibited in vivo by intrahippocampal perfusion of 2-(methylamino)isobutyrate, a competitive and reversible inhibitor of the sodium-coupled neutral amino acid transporter (SNAT) subtypes 1 and 2, as demonstrated by 1.8±0.17 fold elevation of GLNECF (n=7). The frequency of electrographic seizures during uptake inhibition was reduced to 35±7% (n=7) of the frequency in pre-perfusion period, and returned to 88±9% in the post-perfusion period. These novel in vivo results strongly suggest that, in this well-established animal model of temporal-lobe epilepsy, the observed seizure-induced decrease of GLNECF reflects its increased uptake into neurons to sustain enhanced glutamatergic epileptiform activity, thereby demonstrating a possible new target for anti-seizure therapies.

The absence of indoleamine 2,3-dioxygenase expression protects against NMDA receptor-mediated excitotoxicity in mouse brain

We previously showed that the expression and activity of indoleamine 2,3-dioxygenase (Ido1) are chronically elevated in the striatum of YAC128 mouse model of HD. This was followed by increased production of neurotoxic metabolite hydroxykynurenine (3-HK) in the striatum of symptomatic mice. We therefore hypothesized that the chronic Ido1 induction in the striatum of YAC128 mice leads to increased neurotoxicity in this mouse model; based on this hypothesis, we predicted that the absence of Ido1 expression would result in decreased sensitivity to neurotoxicity in mice. The work described in this brief communication will include the characterization of Ido(-/-) striatum in terms of enzymatic expression and activity in the first step of the pathway. Additionally, we assessed the sensitivity of the striatum to excitotoxic insult in the absence of Ido1 expression in the striatum of constitutive Ido1 null mice (Ido(-/-)) and demonstrated that Ido(-/-) mice are less sensitive to QA-induced striatal neurotoxicity. Finally, through measurement of kynurenine pathway (KP) metabolites in Ido(-/-) mice, we showed decreased levels of 3-HK in the striatum of these mice. This study suggests that the inhibition of the first step in the KP may be neuroprotective and should be considered as a potential therapeutic target in HD and other neurodegenerative diseases.

Bupropion attenuates kainic acid-induced seizures and neuronal cell death in rat hippocampus

Excessive release of glutamate is believed to be a major component of cell damage following excitotoxicity associated with epilepsy. Bupropion, an atypical antidepressant, has been shown to inhibit glutamate release from rat cerebrocortical nerve terminals. The present study was undertaken to investigate whether bupropion has anti-seizure and anti-excitotoxic effects by using a kainic acid (KA) rat seizure model, an animal model for temporal lobe epilepsy and excitotoxic neurodegeneration. Our results show that bupropion (10 or 50mg/kg), administrated intraperitoneally to the rats 30 min before the KA (15 mg/kg) intraperitoneal injection, increased the seizure latency and decreased the seizure score. Bupropion pretreatment attenuated KA-induced neuronal cell death and microglia activation in the CA3 region of the hippocampus. Furthermore, KA-induced c-Fos expression and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in the hippocampus were also reduced by bupropion pretreatment. These results suggest that bupropion has therapeutic potential in the treatment of seizure and other neurological diseases associated with excitotoxicity.

Glycyrrhizin attenuates kainic Acid-induced neuronal cell death in the mouse hippocampus

Glycyrrhizin (GL), a triterpene that is present in the roots and rhizomes of licorice (Glycyrrhiza glabra), has been reported to have anti-inflammatory and anti-viral effects. Recently, we demonstrated that GL produced the neuroprotective effects with the suppression of microglia activation and proinflammatory cytokine induction in the postischemic brain with middle cerebral artery occlusion (MCAO) in rats and improved motor impairment and neurological deficits. In the present study, we investigated whether GL has a beneficial effect in kainic acid (KA)-induced neuronal death model. Intracerebroventricular (i.c.v.) injection of 0.94 nmole (0.2 µg) of KA produced typical neuronal death in both CA1 and CA3 regions of the hippocampus. In contrast, administration of GL (10 mg/kg, i.p.) 30 min before KA administration significantly suppressed the neuronal death, and this protective effect was more stronger at 50 mg/kg. Moreover, the GL-mediated neuroprotection was accompanied with the suppression of gliosis and induction of proinflammatory markers (COX-2, iNOS, and TNF-α). The anti-inflammatory and anti-excitotoxic effects of GL were verified in LPS-treated primary microglial cultures and in NMDA- or KA-treated primary cortical cultures. Together these results suggest that GL confers the neuroprotection through the mechanism of anti-inflammatory and anti-excitotoxic effects in KA-treated brain.

New insights into the melanophilin (MLPH) gene controlling coat color phenotypes in American mink

The mutation causing the Silverblue color type (pp) is one of the most used recessive mutations within American mink (Neovison vison) fur farming, since it is involved in some of the popular color types such as Violet and Saphire which originate from a combination of recessive mutations. In the present study, the genomic and mRNA sequences of the melanophilin (MLPH) gene were studied in Violet, Silverblue and wild-type (wt) mink animals. Although breeding schemes and previous literature indicates that the Violet (aammpp) phenotype is a triple recessive color type involving the same locus as the Silverblue (pp) color type, our findings indicate different genotypes at the MLPH locus. Upon comparison at genomic level, we identified two deletions of the entire intron 7 and of the 5' end of intron 8 in the sequence of the Silverblue MLPH gene. When investigating the mRNA, the Silverblue animals completely lack exon 8, which encodes 65 residues, of which 47 define the Myosin Va (MYO5A) binding domain. This may cause the incorrect anchoring of the MLPH protein to MYO5A in Silverblue animals, resulting in an improper pigmentation as seen in diluted phenotypes. Additionally, in the MLPH mRNA of wt, Violet and Silverblue phenotypes, part of intron 8 is retained resulting in a truncated MLPH protein, which is 359 residues long in wt and Violet and 284 residues long in Silverblue. Subsequently, our findings point out that the missing actin-binding domain, in neither of the 3 analyzed phenotypes affects the transport of melanosomes or the consequent final pigmentation. Moreover, the loss of the major part of the MYO5A domain in the Silverblue MLPH protein seems to be the responsible for the dilute phenotype. Based on our genomic DNA data, genetic tests for selecting Silverblue and Violet carrier animals can be performed in American mink.

A developmental perspective on adult hippocampal neurogenesis

The generation of new neurons from neural stem cells (NSCs) throughout adult life in the mammalian brain is a biological process that fascinates scientists for its uniqueness and restorative potential. In the dentate gyrus (DG) of the hippocampus NSCs are able to self-renew and generate new granule cells and astrocytes through a complex and plastic mechanism that can be regulated by endogenous and exogenous cues at different levels. Unexpected recent findings suggest that the population of NSCs is heterogeneous in morphology and behavior. We herein explore the hypothesis that NSC heterogeneity and the neurogenic potential of the DG depends on their developmental origin. We provide an up-to-date picture of the process of neurogenesis in the adult hippocampus with an especial focus on NSCs and outline key unsolved aspects. Further, we discuss the origin of NSCs in the adult DG from a developmental perspective and explore the possibility of NSC heterogeneity being determined from early postnatal periods and being responsible for the neurogenic output of the DG in the long term.