The acute-to-chronic glycemic ratio correlates with the severity of illness at admission in patients with diabetes experiencing acute ischemic stroke.

Acute hyperglycemia is a powerful indicator of the severity of acute ischemic stroke (AIS); however, the relationship between these two factors is not very clear in patients with diabetes. We aimed to retrospectively evaluate data from 335 consecutive patients who experienced AIS from November 2015 to November 2016 to investigate whether a comprehensive assessment of blood glucose levels is a more valuable indicator of the severity of AIS or the presence of acute hyperglycemia in patients with diabetes. We collected demographic data, clinical manifestation information, clinical scores, and laboratory data [including fasting blood glucose and glycated hemoglobin (HbA1c) levels]. We estimated prehospital mean blood glucose concentrations using the following formula [1.59 * HbA1c (%) - 2.59] to calculate the "Acute-to-Chronic Glycemic Ratio" (AC ratio). The AC ratio differed significantly among patients grouped according to the National Institutes of Health Stroke Scale/Score (NIHSS) at admission (admission NIHSS) (p = 0.006). Univariate regression analysis revealed a correlation between the AC ratio and admission NIHSS [standardized ß-coefficient (Std. B) = 0.164, p = 0.004]. The adjusted linear regression analysis revealed a correlation between both HbA1c (Std. B = 0.368, p = 0.038) and the AC ratio (Std. B = 0.262, p = 0.022) and admission NIHSS. The AC ratio (Std. B = 0.161, p = 0.012) was related to admission NIHSS in the stepwise variable selection. For an admission NIHHS > 4, the AC ratio (Std. B = 0.186, p = 0.047) was related to admission NIHSS in the stepwise variable selection. The AC ratio (Std. B = 1.163, p = 0.006 and Std. B = 0.565, p = 0.021, respectively) were related to admission NIHSS in both large-artery atherosclerosis (LAA) and small-vessel occlusion (SVO) subgroups. Thus, the AC ratio is related to admission NIHSS in patients with diabetes who experienced AIS and may be a better indicator of severity than acute blood glucose levels.

Blocking the EGFR/p38/NF-κB signaling pathway alleviates disruption of BSCB and subsequent inflammation after spinal cord injury.

Epidermal growth factor receptor (EGFR) activation is involved in blood spinal cord barrier (BSCB) disruption and secondary injury after spinal cord injury (SCI). However, the underlying mechanisms of EGFR activation mediating BSCB disruption and secondary injury after SCI remain unclear. An in vitro model of oxygen and glucose deprivation/reoxygenation (OGD/R) induced BSCB damage and in vivo rat SCI model were employed to define the role of EGFR/p38/NF-κB signal pathway activation and its induced inflammatory injury in main cellular components of BSCB. Genetic regulation (lentivirus delivered shRNA and overexpression system) or chemical intervention (agonist or inhibitor) were applied to activate or inactivate EGFR and p38 in astrocytes and microvascular endothelial cells (MEC) under which conditions, the expression of pro-inflammatory factors (TNF-α, iNOS, COX-2, and IL-1ß), tight junction (TJ) protein (ZO-1 and occludin), nuclear translocation of NF-κB and permeability of BSCB were analyzed. The pEGFR was increased in astrocytes and MEC which induced the activation of EGFR and p38 and NF-κB nuclear translocation. The activation of EGFR and p38 increased the TNF-α, iNOS, COX-2, and IL-1ß responsible for the inflammatory injury and reduced the ZO-1 and occludin which caused BSCB disruption. While EGFR or p38 inactivation inhibited NF-κB nuclear translocation, and markedly attenuated the production of pro-inflammatory factors and the loss of TJ protein. This study suggests that the EGFR activation in main cellular components of BSCB after SCI mediates BSCB disruption and secondary inflammatory injury via the EGFR/p38/NF-κB pathway.

The microenvironment following oxygen glucose deprivation/re-oxygenation-induced BSCB damage in vitro.

OBJECTIVE: To characterize the microenvironment following blood-spinal cord barrier (BSCB) damage and to evaluate the role of BSCB disruption in secondary damage of spinal cord injury (SCI). METHODS: A model of BSCB damage was established by co-culture of primary microvascular endothelial cells and glial cells obtained from rat spinal cord tissue followed by oxygen glucose deprivation/re-oxygenation (OGD/R). Permeability was evaluated by measuring the transendothelial electrical resistance (TEER) and the leakage test of Fluorescein isothiocyanate-dextran (FITC-dextran). The expression of tight junction (TJ) proteins (occludin and zonula occludens-1 (ZO-1) were evaluated by Western blot and immunofluorescence microscopy. Proinflammatory factors (TNF-α, iNOS, COX-2 and IL-1ß), leukocyte chemotactic factors (MIP-1α, MIP-1ß) and leukocyte adhesion factors (ICAM-1, VCAM-1) were detected in the culture medium under different conditions by enzyme-linked immuno sorbent assay (ELISA). RESULTS: The model of BSCB damage induced by OGD/R was successfully constructed. The maximum BSCB permeability occurred 6-12 hours but not within the first 3 h after OGD/R-induced damage. Likewise, the most significant period of TJ protein loss was also detected 6-12 hours after induction. During the hyper-acute period (3 h) following OGD/R-induced damage of BSCB, leukocyte chemotactic factors and leukocyte adhesion factors were significantly increased in the BSCB model. Pro-inflammation factors (TNF-α, IL-1ß, iNOS, COX-2), leukocyte chemotactic factors (MIP-1α, MIP-1ß) and leukocyte adhesion factors (ICAM-1, VCAM-1) were also sharply produced during the acute period (3-6 hours) and maintained plateau levels 6-12 hours following OGD/R-induced damage, which overlapped with the period of BSCB permeability maximum. A negative linear correlation was observed between the abundance of proinflammatory factors and the expression of TJ proteins (ZO-1 and occludin) and transepithelial electrical resistance (TEER), and a positive linear correlation was found with transendothelial FITC-dextran. CONCLUSIONS: Secondary damage continues after primary BSCB damage induced by OGD/R, exhibiting close ties with inflammation injury.

Blood oxygen level-dependent signals via fMRI in the mood-regulating circuit using two animal models of depression are reversed by chronic escitalopram treatment.

BACKGROUND: People exposed to stressful experience are at increased risk of the development of depression. A number of functional imaging studies have found disturbances in the mood-regulating circuit of the stress-exposed depressed patients, although few animal imaging studies have been undertaken addressing the brain functional changes of depression. METHODS: Two rat models of depression: maternal separation (MS) and chronic unpredictable mild stress (CUMS), imitating early life stress and adult stress respectively, were administered with escitalopram. The differences in functional brain changes were determined by blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI). RESULTS: Increased BOLD activation was observed in some brain regions of MS and CUMS animals, such as the bilateral hypothalamus, limbic system, hippocampus and frontal lobe, which were parts of mood-regulating circuit. Furthermore, the MS- and CUMS-induced increases in BOLD activation were partially attenuated by chronic escitalopram treatment. CONCLUSIONS: These results suggested hyperactivation of mood-regulating circuit at baseline in the depressed animals exposed to stressful experience, and escitalopram can at least partially reverse these effects.

The Role of the Two-Pore Domain Potassium Channel TREK-1 in the Therapeutic Effects of Escitalopram in a Rat Model of Poststroke Depression.

AIM: Poststroke depression (PSD) is one of the most common neuropsychiatric complications after stroke. TREK-1, a two-pore-domain potassium channel, has been implicated in the pathogenesis of stroke and depression. The aim of this study was to investigate whether TREK-1 plays a role in the therapeutic effects of the selective serotonin reuptake inhibitor (SSRI) escitalopram in a rat PSD model. METHODS: The whole-cell patch-clamp technique was performed to assess the effect of escitalopram on recombinant TREK-1 currents in HEK293 cells. The expression of TREK-1 mRNA and protein was measured in the hippocampus and prefrontal cortex (PFC), and neural stem cell (NSC) proliferation was detected in the hippocampal dentate gyrus (DG) in PSD rats after 3 weeks of escitalopram administration. RESULTS: Escitalopram reversibly inhibited TREK-1 currents in a concentration-dependent manner. Chronic treatment with escitalopram significantly reversed the reductions in weight gain, locomotor activity, and sucrose preference in PSD rats. The expressions of TREK-1 mRNA and protein were significantly increased in hippocampal CA1, CA3, DG, and PFC in PSD rats, with the exception of TREK-1 mRNA in hippocampal CA1. NSC proliferation was significantly decreased in hippocampal DG of PSD rats. Escitalopram significantly reversed the regional increases of TREK-1 expression and the reduction of hippocampal NSC proliferation in PSD rats. CONCLUSION: TREK-1 plays an important role in the therapeutic effects of the SSRI escitalopram in PSD model, making TREK-1 an attractive candidate molecule for further understanding the pathophysiology and treatment of PSD.

Protein kinase Mζ is involved in the modulatory effect of fluoxetine on hippocampal neurogenesis in vitro.

The efficacy of chronic selective serotonin reuptake inhibitors (SSRIs) on depression is paralleled by the recovery of deficits in hippocampal neurogenesis related to sustained stress and elevated glucocorticoids. Previous studies have shown that atypical protein kinase C (aPKC) is implicated in the regulation of neurogenesis and the antidepressant response. Whether the specific aPKC isoforms (PKCζ, PKMζ and PKCι) are involved in SSRI-induced hippocampal neurogenesis and the underlying mechanisms is unknown. The present study shows that PKMζ and PKCι but not PKCζ are expressed in rat embryonic hippocampal neural stem cells (NSCs), whereas PKMζ but not PKCι expression is increased by the SSRI fluoxetine both in the absence and presence of the glucocorticoid receptor agonist dexamethasone. PKMζ shRNA significantly decreased neuronal proliferation and neuron-oriented differentiation, increased NSC apoptosis, and blocked the stimulatory effect of fluoxetine on NSC neurogenesis. Fluoxetine significantly increased PKMζ expression in hippocampal NSCs in a 5-hydroxytryptamine-1A (5-HT1A) receptor-dependent manner in both the absence and presence of dexamethasone. The PKMζ peptide blocker ZIP and MEK inhibitor U0126 significantly inhibited the increase in extracellular signal-regulated kinase 1/2 and cyclic adenosine monophosphate response element binding protein phosphorylation in the mitogen-activated protein kinase (MAPK) pathway and hippocampal NSC neurogenesis in response to fluoxetine and the 5-HT1A receptor agonist 8-OH DPAT. Collectively, our results suggest that the SSRI fluoxetine increases hippocampal NSC neurogenesis via a PKMζ-mediated mechanism that links 5-HT1A receptor activation with the phosphorylation of the downstream MAPK signaling pathway.

Hippocampal neurochemistry is involved in the behavioural effects of neonatal maternal separation and their reversal by post-weaning environmental enrichment: a magnetic resonance study.

Exposure to early life stress results in behavioural changes, and these dysfunctions may persist throughout adulthood. In this study, we investigated whether hippocampus volume and neurochemical changes were involved in the appearance of these effects in the maternal separation (MS) animal model using the noninvasive techniques of structural magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Sprague-Dawley rats exposed to MS for 180 min from postnatal days (PND) 2-14 demonstrated decreased sucrose preference, increased immobility in the forced swimming test (FST), and impaired memory in the Morris water maze in adulthood. Environmental enrichment (EE) (PND 21-60) could ameliorate the effects of MS on sucrose preference and learning and memory but not on immobility in the FST. In addition, EE significantly increased N-acetylaspartate (NAA) of MS animals. However, we did not find an effect of MS or EE on hippocampal volume. These results indicate the involvement of hippocampal neurochemistry in the behavioural changes that result from early stressful life events and their modification by post-weaning EE. Thus changes in NAA, as a measure of neuronal integrity, appear to be a sensitive correlate of these behavioural effects.