Effects of lithium on cytokine neuro-inflammatory mediators, Wnt/ß-catenin signaling and microglial activation in the hippocampus of chronic mild stress-exposed rats.

Microglial in vivo production of pro-inflammatory cytokines is central to the pathogenesis of multiple neurological disorders including depression, with a rising role of Wnt/ß-catenin signaling as potential regulator of microglia-mediated neuro-inflammation. This study aimed at investigating the hippocampal expression of the Wnt/ß-catenin pathway in chronic mild stress (CMS)-exposed rats and the effects of Lithium (Li) on the expression of this pathway as a method to identify a plausible link between exposure to chronic stress, microglial activation, and neuroinflammation. METHODS: The effect of chronic administration of Li was investigated on behavioral changes, hippocampal expression of Wnt-DVL-GSK3ß-ß-catenin signaling pathway, and microglial activation in CMS-exposed male Wistar rats RESULTS: CMS induced a depressive-like behavior associated with increased pro-inflammatory microglial activation and reduced hippocampal expression of the Wnt/ß-catenin signaling pathway. Chronic Li treatment ameliorated stress induced-behavioral changes, reduced microglial activation and enhanced the hippocampal expression of Wnt/ß-catenin signaling pathway. CONCLUSION: This work highlights that Li-induced inhibition of GSK-3ß with subsequent accumulation of ß-catenin could impede pro-inflammatory microglia activation which is a key pathological hallmark associated with depression. Wnt/ß-catenin signaling represents a promising therapeutic target, not only for alleviation of depression, but also for a wide array of neurological disorders.

Potential neuroprotective effect of androst-5-ene-3ß, 17ß-diol (ADIOL) on the striatum, and substantia nigra in Parkinson's disease rat model.

Parkinson's disease (PD) is a progressive neurodegenerative disorder with behavioral and motor abnormalities. Androst-5-ene-3ß, 17ß-diol (ADIOL), an estrogen receptor (ER) ß agonist, was found to mediate a transrepressive mechanism that selectively modulates the extent of neuroinflammation and, in turn, neurodegeneration. In consensus, ERß polymorphism was more frequently detected in early-onset PD patients. Thus, in an approach to elucidate the role of ERß agonists on PD, our study was designed to investigate the possible neuroprotective effect of ADIOL, in three dose levels (0.35, 3.5, 35 mg/kg/day), against rotenone (ROT)-induced PD rat model. Amelioration in striatal dopamine (DA), nuclear factor-kappa B (NF-κB), and the expression of down-stream inflammatory mediators, as well as apoptotic markers were observed in the striatum and substantia nigra (SN) upon pre-treatment with the three doses of ADIOL. Similarly, light microscopy (LM) examination revealed declined degeneration of neurons upon pretreatment with ADIOL. Significant improvement in nigral tyrosine hydroxylase (TH) and reduction of nigral α-synuclein densities were also detected after ADIOL pre-treatment with better results frequently achieved with the middle dose (3.5 mg/kg/day). The middle dose of ADIOL showed behavioral improvement, with elevation in the ATP level, which was emphasized by the improvement in mitochondrial integrity observed upon electron microscopy (EM) examination. In conclusion, the present study confirmed for the first time the ability of ADIOL to protect against neuroinflammation and, in turn, neurodegeneration process and motor dysfunction in PD animal model, which was more obviously observed with the middle dose.

Behavioural, metabolic, and endothelial effects of the TNF-α suppressor thalidomide on rats subjected to chronic mild stress and fed an atherogenic diet.

There is accumulating evidence suggesting that depression is a risk factor for cardiovascular diseases. This study aimed to examine the hypothesis that the proinflammatory cytokine TNF-α would partially explain the link between depression and atherosclerotic endothelial changes. Rats were distributed among 6 groups: (i) control group; (ii) group subjected to chronic mild stress (CMS); (iii) group fed a cholesterol-cholic acid-thiouracil (CCT diet); and (iv) CMS group fed the CCT diet and treated with the vehicle for 8 weeks. The last 2 groups were subjected to CMS-CCT and received thalidomide (THAL) or imipramine (IMIP). Rats were assessed behaviorally (sucrose preference, open field, and forced-swimming tests). TNF-α protein was assessed from the serum, aorta, and liver. Aortic TNF-α gene expression (assessed using RT-PCR), serum lipid profile, and insulin levels were measured. Endothelial function was assessed in isolated aortic rings. The THAL and IMIP groups showed ameliorated CMS-CCT-related behavioral changes. CMS-CCT-induced metabolic and endothelial dysfunctions were improved in the THAL group but were worsened in the IMIP group. RT-PCR showed a significant reduction of aortic TNF-α mRNA expression in the THAL and IMIP treatment groups. These data paralleled the findings for aortic immunohistochemistry. The THAL group, but not the IMIP group, showed improved CMS-CCT-induced changes in the vascular reactivity of the aortic rings. Thus, TNF-α provides a target link between depression, metabolic syndrome, and endothelial dysfunction. This could open a new therapeutic approach to address the comorbidities of depression.

Cognitive effects of the GSK-3 inhibitor "lithium" in LPS/chronic mild stress rat model of depression: Hippocampal and cortical neuroinflammation and tauopathy.

Low-dose repeated lipopolysaccharide pre-challenge followed by chronic mild stress (LPS/CMS) protocol has been introduced as a rodent model of depression combining the roles of immune activation and chronic psychological stress. However, the impact of this paradigm on cognitive functioning has not been investigated hitherto. METHODS: This study evaluated LPS/CMS-induced cognitive effects and the role of glycogen synthase kinase-3ß (GSK-3ß) activation with subsequent neuroinflammation and pathological tau deposition in the pathogenesis of these effects using lithium (Li) as a tool for GSK-3 inhibition. RESULTS: LPS pre-challenge reduced CMS-induced neuroinflammation, depressive-like behavior and cognitive inflexibility. It also improved spatial learning but increased GSK-3ß expression and exaggerated hyperphosphorylated tau accumulation in hippocampus and prefrontal cortex. Li ameliorated CMS and LPS/CMS-induced depressive and cognitive deficits, reduced GSK-3ß over-expression and tau hyperphosphorylation, impeded neuroinflammation and enhanced neuronal survival. CONCLUSION: This study draws attention to LPS/CMS-triggered cognitive changes and highlights how prior low-dose immune challenge could develop an adaptive capacity to buffer inflammatory damage and maintain the cognitive abilities necessary to withstand threats. This work also underscores the favorable effect of Li (as a GSK-3ß inhibitor) in impeding exaggerated tauopathy and neuroinflammation, rescuing neuronal survival and preserving cognitive functions. Yet, further in-depth studies utilizing different low-dose LPS challenge schedules are needed to elucidate the complex interactions between immune activation and chronic stress exposure.

Albendazole and its metabolites in the breast milk of lactating women following a single oral dose of albendazole.

AIMS: Albendazole (ABZ) is used in several anthelminthic drug programs. ABZ side-effects are generally mild, but ABZ-induced pancytopenia may be serious. In filariasis programmes, it may be necessary to administer ABZ to breastfeeding women. Few data are available on safety of ABZ for breastfed infants. In addition, the pharmacokinetics of ABZ and its metabolites in human milk is insufficiently investigated. The aim was to study pharmacokinetics of ABZ and its metabolites [ABZ sulphoxide (ABSX) and ABZ sulphone] in the breast milk lactating women after one single oral dose of ABZ. METHODS: Thirty-three lactating women (age 18-40 years) participated in the study. They received a single oral 400-mg dose of ABZ. Five milk samples were taken at 0, 6, 12, 24 and 36 h. One serum sample was taken after 6 h. Samples were analysed using high-performance liquid chromatography and pharmacokinetic analysis was performed. RESULTS: ABZ was detectable in milk samples 6 h after the oral dose. The mean concentration of serum ABZ was 63.7 +/- 11.9 ng ml(-1). The pharmacokinetic parameters for ABSX were calculated as follows: 351.9 +/- 32.4 ng ml(-1), 6.9 +/- 0.5 h, 12.4 +/- 2.2 h and 5190.3 +/- 482.8 ng*h ml(-1) for C(max), T(max), t((1/2)) and AUC(0-36), respectively. The milk-to-serum ratios (range) for ABZ and ABSX were 0.9 (0.2-6.5) and 0.6 (0.1-1.5), respectively. CONCLUSIONS: After an oral dose of 400 mg, ABZ and ABSX attain low concentrations in breast milk that are unlikely to be considered harmful for the breastfed infant.

Changes in glutamate decarboxylase enzyme activity and tau-protein phosphorylation in the hippocampus of old rats exposed to chronic mild stress: reversal with the neuronal nitric oxide synthase inhibitor 7-nitroindazole.

Effects of chronic stress are not completely understood. They may underlie depression and dementia. This study assessed the association between chronic stress, glutamate levels, tau-protein phosphorylation, and nitric-oxide in old rats exposed to chronic mild stress (CMS). Old (>15 months) male Wistar rats were exposed to CMS. Comparison groups included old and young control rats, young CMS-exposed, and old CMS-exposed rats treated with the neuronal nitric-oxide synthase (nNOS) enzyme inhibitor, 7-nitroindazole (20 mg/kg/day i.p.). Hippocampal glutamate levels and glutamate decarboxylase (GAD) activity were determined and tau protein phosphorylation was assessed. Age was a significant (p=0.025) source of variation in glutamate level [811.71+/-218.1, 665.9+/-124.9 micromol/g tissue protein (M+/-SD) in young and old control rats, respectively]. Old rats exposed to CMS were characterized by an increased risk to develop anhedonia. There was significant (p=0.035) decrease in GAD enzyme activity (-60.06%) and increased tau protein hyperphosphorylation in old rats exposed to CMS compared to control. Administration of 7-nitroindazole to CMS-exposed old rats significantly (p=0.002) increased GAD activity, decreased glutamate levels (7.19+/-3.19 vs. 763.9+/-91 micromol/g tissue protein; p=0.0005), and decreased phosphorylation of tau proteins compared to CMS exposed rats.

Pentoxifylline ameliorates chronic stress/high-fat diet-induced vascular wall disease: the role of circulating endothelial progenitor cells.

Depression and cardiovascular disease (CVD) are two faces of one coin. A pro-inflammatory state was previously suggested in the pathology of both diseases. We investigated the effect of chronic administration (2 weeks) of imipramine (20 mg/kg/day) and pentoxifylline (50 mg/kg/day) on behavioral, aortic histological abnormalities, and level of circulating endothelial progenitor cells (CEPCs) in peripheral blood of male Wistar rats exposed to chronic mild stress (CMS) and high-fat diet. Exposure to CMS and high-fat diet induced a depressive-like behavior alongside aortic immunohistochemical changes associated with an increase in aortic TNF-α level. Markers of CEPCs, VEGFR-2 and CD133, were significantly disturbed in aortic sections, as compared to control animals and those exposed to CMS while fed high-fat diet, although flowcytometric analysis did not show any significant changes in the level of CEPCs in peripheral blood. Chronic pentoxifylline treatment was more effective in ameliorating the histological changes and endothelial damage compared to imipramine. Pro-inflammatory cytokines-induced disturbances in CEPCs could constitute a plausible link between depression and atherosclerotic cardiovascular disease. Current antidepressants reduce symptoms of depression without tackling the underlying link between it and cardiovascular disease. Targeting pro-inflammatory cytokines might open a new therapeutic approach to alleviate depression and reduce the risk of mortality from cardiovascular disease.

Tetramethylpyrazine Ameliorates Rotenone-Induced Parkinson's Disease in Rats: Involvement of Its Anti-Inflammatory and Anti-Apoptotic Actions.

Parkinson's disease (PD) is a slowly progressive neurodegenerative movement disorder. Apoptosis, neuroinflammation, and oxidative stress are the current hypothesized mechanisms for PD pathogenesis. Tetramethylpyrazine (TMP), the major bioactive component of Ligusticum wallichii Franchat (ChuanXiong), Family Apiaceae, reportedly has anti-apoptotic, anti-inflammatory and antioxidant effects. This study investigated the role of 'TMP' in preventing rotenone-induced neurobiological and behavioral sequelae. A preliminary dose-response study was conducted where rats received TMP (10, 20, and 40 mg/kg, i.p.) concomitantly with rotenone (2 mg/kg, s.c.) for 4 weeks. Catalepsy, locomotor activity, striatal dopamine content, and tyrosine hydroxylase "TH" and α-synuclein immunoreactivity were evaluated. The selected TMP dose (20 mg/kg) was used for western blot analysis of Bax, Bcl2, and DJ-1, immunohistochemical detection of nuclear factor kappa B (NF-кB), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX2), and glial fibrillary acidic protein (GFAP) expression, in addition to biochemical analysis of caspase-3 activity, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) levels. Results showed that TMP (20 mg/kg) significantly improved midbrain and striatal TH expression and striatal dopamine content as well as the motor deficits, compared to rotenone-treated group. These results were correlated with reduction in caspase-3 activity and α-synuclein expression, along with improvement of midbrain and striatal Bax/Bcl2 ratio compared to rotenone-treated group. TMP also attenuated rotenone-induced upregulation of Nrf2/HO-1 pathway. Furthermore, TMP downregulated rotenone-induced neuroinflammation markers: NF-кB, iNOS, COX2, and GFAP expression in both the midbrain and striatum. Taken together, the current study suggests that TMP is entitled to, at least partially, preventing PD neurobiological and behavioral deficits by virtue of its anti-apoptotic, anti-inflammatory, and antioxidant actions.

Paroxetine ameliorates changes in hippocampal energy metabolism in chronic mild stress-exposed rats.

The molecular mechanisms underlying stress-induced depression have not been fully outlined. Hence, the current study aimed at testing the link between behavioral changes in chronic mild stress (CMS) model and changes in hippocampal energy metabolism and the role of paroxetine (PAROX) in ameliorating these changes. Male Wistar rats were divided into three groups: vehicle control, CMS-exposed rats, and CMS-exposed rats receiving PAROX (10 mg/kg/day intraperitoneally). Sucrose preference, open-field, and forced swimming tests were carried out. Corticosterone (CORT) was measured in serum, while adenosine triphosphate and its metabolites, cytosolic cytochrome-c (Cyt-c), caspase-3 (Casp-3), as well as nitric oxide metabolites (NOx) were measured in hippocampal tissue homogenates. CMS-exposed rats showed a decrease in sucrose preference as well as body weight compared to control, which was reversed by PAROX. The latter further ameliorated the CMS-induced elevation of CORT in serum (91.71±1.77 ng/mL vs 124.5±4.44 ng/mL, P<0.001) as well as the changes in adenos-ine triphosphate/adenosine diphosphate (3.76±0.02 nmol/mg protein vs 1.07±0.01 nmol/mg protein, P<0.001). Furthermore, PAROX reduced the expression of Cyt-c and Casp-3, as well as restoring NOx levels. This study highlights the role of PAROX in reversing depressive behavior associated with stress-induced apoptosis and changes in hippocampal energy metabolism in the CMS model of depression.

Lipopolysaccharide repeated challenge followed by chronic mild stress protocol introduces a combined model of depression in rats: reversibility by imipramine and pentoxifylline.

OBJECTIVES: The present study examined the effect of combined exposure to repeated challenge using low doses of lipopolysaccharide (LPS) and chronic mild stress (CMS) together. This combined exposure is thought to expose the animals to more realistic challenges, testable on different levels (behavioral, neurochemical, immunohistochemical and gene expression). The role of glial cells was examined, as well. Additionally, the effects of chronic administration of the tricyclic antidepressant imipramine and the anti-TNF-α pentoxyphylline were investigated. METHODS: Wistar rats were exposed to either repeated LPS (50µg/kg i.p.) over 2weeks, CMS protocol for 4weeks or LPS over 2weeks then 4weeks of CMS. Two groups of rats were exposed to LPS/CMS protocol and treated with either imipramine or pentoxifylline. Rats were examined for behavioral, neurochemical and gene expression changes. RESULTS: Animals exposed to LPS/CMS elaborated depressive-like symptoms with significant increase in both serum corticosterone and TNF-α levels compared to those in the saline, LPS or CMS groups. Hippocampal kynurenine/tryptophan ratio and TNF-α gene expression showed significant increase in the LPS/CMS model compared to those in saline, LPS or CMS groups. The immunohistochemical findings scrutinized the topography of the examined effects. Chronic treatment with imipramine or pentoxifylline significantly ameliorated the behavioral, neurochemical, immunohistochemical and TNF-α gene expression changes induced by the LPS/CMS protocol. CONCLUSION: This study gave a clue to the neurobiological processes underlying, at least, the subtypes of depressive disorders. It highlighted the possible interactions between stress and immune-inflammatory pathways in the pathogenesis of depression and suggested a new animal model of depression that addresses these pathways.

Effects of pentoxifylline, 7-nitroindazole, and imipramine on tumor necrosis factor-α and indoleamine 2,3-dioxygenase enzyme activity in the hippocampus and frontal cortex of chronic mild-stress-exposed rats.

OBJECTIVES: This study aimed to investigate the role of tumor necrosis factor (TNF)-α and the neuronal nitric oxide synthase enzyme in dysregulation of indoleamine 2,3-dioxygenase (IDO) enzyme, and hence serotonin availability in chronic mild stress (CMS), an animal model of depression. METHODS: RATS WERE DIVIDED INTO FIVE GROUPS: two control and CMS-exposed for 6 weeks, and another three groups exposed to CMS and administered pentoxifylline 50 mg/kg/day intraperitoneally, 7-nitroindazole 40 mg/kg/day subcutaneously, or imipramine 20 mg/kg/day intraperitoneally for the previous 3 CMS weeks. Rats were assessed for neurochemical and immunohistochemical abnormalities. RESULTS: Pentoxifylline-, 7-nitroindazole-, and imipramine-treated rats showed amelioration of CMS-induced behavioral deficits that was accompanied by significant reduction in kynurenine/serotonin molar ratio and nitrates/nitrites in frontal cortex and hippocampus. In the pentoxifylline and 7-nitroindazole groups, serum TNF-α was reduced relative to the CMS group (18.54 ± 0.85 and 19.16 ± 1.54 vs 26.20 ± 1.83 pg/mL, respectively; P < 0.05). Exposure to CMS increased TNF-α and IDO immunohistochemical staining scores in both hippocampus and midbrain raphe nuclei. 7-Nitroindazole and pentoxifylline significantly (P < 0.05) reduced TNF-α immunostaining in hippocampus and raphe nuclei, with significant (P < 0.01) reduction of IDO immunostaining in raphe nuclei. Likewise, imipramine reduced TNF-α immunostaining (P < 0.05) in hippocampus. CONCLUSION: Neuronal nitric oxide synthase and TNF-α may play a concerted role in modulating IDO enzyme activity in CMS-exposed rats and provide additional evidence for possible alternative approaches to switch the neurobiological processes in depression.

Potential neuroprotective effects of hesperidin on 3-nitropropionic acid-induced neurotoxicity in rats.

Huntington's disease (HD) is a progressive neurodegenerative disorder with a spectrum of cognitive, behavioral, and motor abnormalities. The mitochondrial toxin 3-nitropropionic acid (3-NP) effectively induces specific behavioral changes, primarily manifested as prepulse inhibition (PPI) deficit of acoustic startle stimuli, and selective striatal lesions in rats and primates mimicking those in HD. The implications of nitric oxide in a variety of neurodegenerative diseases attract attention to study the possible role of flavonoids in interaction with nitric oxide pathways involved in HD. The present study investigates the potential effect of hesperidin, a flavanone group member, on 3-NP-induced behavioral, neurochemical, histopathological and cellular changes. Systemic administration of 3-NP to rats for 5 days (20 mg/kg) caused reduction of locomotor activity by days 2 and 5, 55% deficit of PPI response, elevation of cortical, striatal and hippocampal malondialdehyde (MDA) levels by 63%, 41% and 56%, reduction of respective catalase activity by 50%. Immunohistochemical staining of cortices, striata and hippocampi showed patches of iNOS positive cells. Electron microscopic ultrastructural examination showed marked mitochondrial swelling, perivascular edema and shrunken nerve cells. Pretreatment with hesperidin (100 mg/kg) ahead of 3-NP prevented any changes of locomotor activity or PPI response, slightly increased cortical, striatal and hippocampal MDA levels by 10% and reduced respective catalase activity by 22%, 20% and 5%. Only few iNOS positive cells were detected in sections from rats pretreated with hesperidin which also reduced cellular abnormalities induced by 3-NP. This study suggests a potential neuroprotective role of hesperidin against 3-NP-induced Huntington's disease-like manifestations. Such neuroprotection can be referred to its antioxidant and anti-inflammatory activities.

Acetylator phenotyping in patients with malignant lymphomas, using caffeine as the metabolic probe.

OBJECTIVE: The study was designed to answer the question whether a particular (slow/fast) acetylator phenotype is a risk for malignant lymphoma patients. Differences in acetylator phenotypes were previously described in urinary bladder and colorectal carcinoma patients compared to controls. Addressing this issue may help understanding the possible role of xenobiotics' metabolism in the pathogenesis of malignant lymphomas. Caffeine is currently preferred as a metabolic probe due to its noninvasiveness. DESIGN: Case-control study. SETTING: Hematology/oncology inpatient unit and outpatient clinic, Ain Shams University Hospitals, Cairo, Egypt: a tertiary care academic medical institution. PARTICIPANTS: Urine samples were collected 4 h after the oral administration of a caffeine-containing beverage to 83 patients with malignant lymphomas and 92 control subjects. Diagnosis of lymphoma was ascertained histopathologically. Controls were matched in terms of age, sex and residence (urban/rural). MEASUREMENTS: To define the acetylation phenotype, the nanomolar ratio of the urinary concentrations of the caffeine metabolites: acetylamino-6-amino-3-methyluracil and 1-methylxanthine (AAMU/1X) was calculated for every study subject. RESULTS: An excess of fast acetylators was shown in the malignant lymphoma group compared to the control. The odds ratio for malignant lymphoma associated with fast acetylation was 1.304 (95% CI, 0.709-2.398; p = 0.439). Paradoxically, an excess of the slow acetylator phenotype was observed in patients with low-grade non-Hodgkin lymphoma (n = 25) compared to other subjects of the lymphoma group. The odds ratio for low-grade lymphoma associated with slow acetylation was 4.00 (95% CI, 1.316-12.155; p = 0.014). CONCLUSIONS: Owing to the small sample size, the association between the acetylator phenotype and malignant lymphomas could not be excluded. However, the study suggests that, compared to other types of lymphoma, low-grade non-Hodgkin lymphoma would be associated with slow acetylator phenotype.