Abstract We used field potential recordings in an in vitro thalamocortical slice preparation to compare the rhythmic oscillations generated by reciprocally connected networks of the thalamus and cerebral cortex obtained from epileptic (> 160 days old) WAG/Rij and age‐matched, nonepileptic control (NEC) rats. To increase neuronal excitability, and thus to elicit spontaneous field potential activity in vitro , we applied medium containing: (i) zero [Mg 2+ ]; (ii) high [K + ] (8.25 m m ); or (iii) low concentrations of the K + channel blocker 4‐aminopyridine (4AP, 0.5–1 µ m ). Of these procedures, only the last was effective in triggering oscillatory activity that depended on the type of tissue. Thus, during 4AP application: (i) sequences of fast (intraburst frequency 9.5–16.1 Hz) and slower (5–8.9 Hz) field potential oscillations (FPOs) were recorded in WAG/Rij slices ( n = 23), but (ii) only fast FPOs were seen in NEC slices ( n = 7). Slower FPOs in WAG/Rij slices reflected a larger degree of thalamocortical synchronization than fast FPOs, and disappeared after surgical separation of cortex and thalamus ( n = 5); under these conditions fast FPOs continued to occur in thalamus only. In addition, fast and slower FPOs disappeared in all areas of the WAG/Rij slice during thalamic application of the excitatory amino acid receptor antagonist kynurenic acid ( n = 3), while fast FPOs continued to occur in thalamus when kynurenic acid was applied to the cortex ( n = 4). Bath application of the N ‐methyl‐ d ‐aspartic acid (NMDA) receptor antagonist 3,3‐(2‐carboxypiperazine‐4‐yl)‐propyl‐1‐phosphonate (CPP) abolished slower FPOs in WAG/Rij cortex and thalamus ( n = 6) without infuencing fast FPOs recorded in WAG/Rij ( n = 6) or NEC slices ( n = 4). Moreover, cortical application of CPP ( n = 6) abated slower FPOs although they persisted following CPP application to the thalamus ( n = 7). Our data demonstrate that highly synchronized, slower FPOs can occur during 4AP application in WAG/Rij but not in NEC slices. This activity, which may represent an in vitro hallmark of thalamocortical epileptogenicity, requires the function of reciprocally connected thalamic and cortical networks and depends on cortical NMDA receptor‐mediated mechanisms.
Abstract Background and Aims Autosomal dominant polycystic kidney disease (ADPKD) is the 4th cause of end-stage renal disease in Western Countries, nevertheless still represents an illness with a significant unmet medical need. In recent years, deregulation in glucose metabolism in ADPKD has been identified. Data suggest that cystic cells shift their energy metabolism from oxidative phosphorylation to aerobic glycolysis. Preclinical experiences show beneficial effects in terms of cystic size reduction, interstitial fibrosis and disease progression, targeting these deregulated metabolic pathways by ketosis induction. A ketogenic diet treatment approach, such as a Modified Atkins Diet (MAD), to ADPKD represents an interesting therapeutic strategy, because of its low cost, tolerability and safety [1]. The Primary Endpoint of this study is the evaluation of the effect of the MAD protocol on the modification of the Total Kidney Volume (TKV), formally qualified, both by FDA and by EMA, as a prognostic enrichment biomarker for selecting patients at high risk for a progressive decline. Method the initial protocol [2] has been modified in a multicentric study that involves the Divisions of Nephrology of AOU Policlinico di Modena (Modena, Italy) and Policlinico di Sant'Orsola (Bologna, Italy). GREASE II is supported by the Italian Ministry of Health (Ricerca Finalizzata grant no. RF-2021-12374522). During the run-in period, 90 patients will follow a Balanced Normocaloric Diet (BND). In the week preceding the randomization, patients will perform a baseline MRI. Patients will be then randomized to MAD or BND according to a stratified 1:1 ratio. Patients will be followed for 12 months at scheduled clinical and dietetic visits. In the 12ve month, the patients on the MAD arm will be switched to BND and a second MRI will be performed after a month (± 7 days). After the MRI, the patients will be switched again to their original MAD. Patients will be followed for further 12 months at scheduled clinical and dietetic visits. At the 24th month, patients of the MAD arm will be switched once again to BND and after a month (± 7 days) a final visit will be performed (Fig. 1). As co-primary endpoint tolerability and safety will be assessed. Furthermore, as secondary outcomes, the study will evaluate renal function decline, total liver volume (TLV) and the impact of the diets on urinary and serum markers β2MG and MCP-1. Results we expect to obtain a reduction of the TKV in the group of patients treated by the MAD protocol. Safety and tolerability are coprimary endpoints of the study. As secondary exploratory outcomes, the study will evaluate the effect of the diet on the TLV and quality of life (ADPKD-IS and SF-12 questionnaires). This clinical trial will allow us to evaluate the proof of concept of the therapeutic efficacy of MAD in the ADPKD clinical setting. Conclusion GREASE II represents the first multicenter RCT evaluating the reduction of the TKV in ADPKD and renal function decline. The identification of a coordinated reduction of TKV and renal function decline in the patients randomized to the MAD compared to the BND will suggest a protective role of the ketogenic diet against disease progression of ADPKD.
Produced by the mitochondria and endoplasmic reticulum, neurosteroids such as allopregnanolone are neuroprotective molecules that influence various neuronal functions and regulate neuroinflammation. They are reduced in neurodegenerative diseases, while in the Wobbler mouse model, allopregnanolone and its precursor progesterone showed protective effects on motor neuron degeneration. This single-center case-control study included 37 patients with amyotrophic lateral sclerosis (ALS) and 28 healthy controls. Cerebrospinal fluid (CSF) neurosteroid levels were quantified using liquid chromatography–electrospray tandem mass spectrometry and compared between the two cohorts. Neurosteroid concentrations have been correlated with neuroinflammation and neurodegeneration biomarkers detected through an automated immunoassay, along with disease features and progression. Pregnenolone, progesterone, allopregnanolone, pregnanolone, and testosterone levels were significantly lower in ALS patients’ CSF compared to healthy controls. A significant inverse correlation was found between neurofilament and neurosteroid levels. Neurosteroid concentrations did not correlate with disease progression, phenotype, genotype, or survival prediction. Our study suggests the independence of the disease features and its progression, from the dysregulation of neurosteroids in ALS patients’ CSF. This neurosteroid reduction may relate to disease pathogenesis or be a consequence of disease-related processes, warranting further research. The inverse correlation between neurosteroids and neurofilament levels may indicate a failure of compensatory neuroprotective mechanisms against neurodegeneration.
Multiple sclerosis (MS) is an autoimmune demyelinating disorder of the central nervous system (CNS) characterized by loss of myelin accompanied by infiltration of T‐lymphocytes and monocytes. Although it has been shown that these infiltrates are important for the progression of MS, the role of microglia, the resident macrophages of the CNS, remains ambiguous. Therefore, we have compared the phenotypes of microglia and macrophages in a mouse model for MS, experimental autoimmune encephalomyelitis (EAE). In order to properly discriminate between these two cell types, microglia were defined as CD11b pos CD45 int Ly‐6C neg , and infiltrated macrophages as CD11b pos CD45 high Ly‐6C pos . During clinical EAE, microglia displayed a weakly immune‐activated phenotype, based on the expression of MHCII, co‐stimulatory molecules (CD80, CD86, and CD40) and proinflammatory genes [interleukin‐1β (IL‐1β) and tumour necrosis factor‐ α (TNF‐α)]. In contrast, CD11b pos CD45 high Ly‐6C pos infiltrated macrophages were strongly activated and could be divided into two populations Ly‐6C int and Ly‐6C high , respectively. Ly‐6C high macrophages contained less myelin than Ly‐6C int macrophages and expression levels of the proinflammatory cytokines IL‐1β and TNF‐α were higher in Ly‐6C int macrophages. Together, our data show that during clinical EAE, microglia are only weakly activated whereas infiltrated macrophages are highly immune reactive. GLIA 2014;62:1724–1735
Fragile X syndrome (FXS), a common inherited form of mental impairment and autism, is caused by transcriptional silencing of the fragile X mental retardation 1 (FMR1) gene. Earlier studies have identified a role for aberrant synaptic plasticity mediated by the metabotropic glutamate receptors (mGluRs) in FXS. However, many of these observations are derived primarily from studies in the hippocampus. The strong emotional symptoms of FXS, on the other hand, are likely to involve the amygdala. Unfortunately, little is known about how exactly FXS affects synaptic function in the amygdala. Here, using whole-cell recordings in brain slices from adult Fmr1 knockout mice, we find mGluR-dependent long-term potentiation to be impaired at thalamic inputs to principal neurons in the lateral amygdala. Consistent with this long-term potentiation deficit, surface expression of the AMPA receptor subunit, GluR1, is reduced in the lateral amygdala of knockout mice. In addition to these postsynaptic deficits, lower presynaptic release was manifested by a decrease in the frequency of spontaneous miniature excitatory postsynaptic currents (mEPSCs), increased paired-pulse ratio, and slower use-dependent block of NMDA receptor currents. Strikingly, pharmacological inactivation of mGluR5 with 2-methyl-6-phenylethynyl-pyridine (MPEP) fails to rescue either the deficit in long-term potentiation or surface GluR1. However, the same acute MPEP treatment reverses the decrease in mEPSC frequency, a finding of potential therapeutic relevance. Therefore, our results suggest that synaptic defects in the amygdala of knockout mice are still amenable to pharmacological interventions against mGluR5, albeit in a manner not envisioned in the original hippocampal framework. PMID: 20534533
Indole‐pyruvic acid was studied for its short‐ and long‐term effects on electro‐encephalographic sleep and on food intake in rats implanted with cortical and muscular electrodes. Following a single injection, indole‐pyruvic acid (10–50 mg kg ‐1 i.p.) reduced by 16–23 min (range) the latency of the first slow‐wave episode in a dose‐related fashion and produced a significant increase in slow‐wave sleep time (12–40%) in doses of 10–30 mg kg ‐1 . Rapid eye movement sleep latency and rapid eye movement sleep time were increased (by 23–37 min) and reduced (57–71%) respectively. The effects of indole‐pyruvic acid on slow‐wave sleep time were still present after 3, 7 and 14 days of chronic administration (10 mg kg ‐1 day ‐1 ), whereas tolerance to the effect of indole‐pyruvic acid on rapid eye movement sleep was observed. Daily food consumption was reduced (20–28%) by acute administration of indole‐pyruvic acid (15–30 mg kg ‐1 i.p.), but tolerance developed after 5 days of repeated injections. These findings are in accordance with previous evidence suggesting that indole‐pyruvic acid effects may be related to the activation of central serotonin neurons, which are involved in the inhibitory control of sleep and food intake.
