Moderate maternal food restriction in mice impairs physical growth, behavior, and neurodevelopment of offspring

Intrauterine growth retardation (IUGR) occurs in 3% to 7% of all pregnancies. Recent human studies have indicated that neurodevelopmental disabilities, learning disorders, memory impairment, and mood disturbance are common in IUGR offspring. However, the interactions between IUGR and neurodevelopmental disorders are unclear because of the wide range of causes of IUGR, such as maternal malnutrition, placental insufficiency, pregnancy toxemia, and fetal malformations. Meanwhile, many studies have shown that moderate food restriction enhances spatial learning and improves mood disturbance in adult humans and animals. To date, the effects of maternal moderate food restriction on fetal brain remain largely unknown. In this study, we hypothesized that IUGR would be caused by even moderate food restriction in pregnant females and that the offspring would have neurodevelopmental disabilities. Mid-pregnant mice received moderate food restriction through the early lactation period. The offspring were tested for aspects of physical development, behavior, and neurodevelopment. The results showed that moderate maternal food restriction induced IUGR. Offspring had low birth weight and delayed development of physical and coordinated movement. Moreover, IUGR offspring exhibited mental disabilities such as anxiety and poor cognitive function. In particular, male offspring exhibited significantly impaired cognitive function at 3 weeks of age. These results suggested that a restricted maternal diet could be a risk factor for developmental disability in IUGR offspring and that male offspring might be especially susceptible.

Hypothalamic 2-arachidonoylglycerol regulates multistage process of high-fat diet preferences

Background

In this study, we examined alterations in the hypothalamic reward system related to high-fat diet (HFD) preferences. We previously reported that hypothalamic 2-arachidonoylglycerol (2-AG) and glial fibrillary acid protein (GFAP) were increased after conditioning to the rewarding properties of a HFD. Here, we hypothesized that increased 2-AG influences the hypothalamic reward system.

Methods

The conditioned place preference test (CPP test) was used to evaluate HFD preferences. Hypothalamic 2-AG was quantified by gas chromatography-mass spectrometry. The expression of GFAP was examined by immunostaining and western blotting.

Results

Consumption of a HFD over either 3 or 7 days increased HFD preferences and transiently increased hypothalamic 2-AG levels. HFD consumption over 14 days similarly increased HFD preferences but elicited a long-lasting increase in hypothalamic 2-AG and GFAP levels. The cannabinoid 1 receptor antagonist O-2050 reduced preferences for HFDs after 3, 7, or 14 days of HFD consumption and reduced expression of GFAP after 14 days of HFD consumption. The astrocyte metabolic inhibitor Fluorocitrate blocked HFD preferences after 14 days of HFD consumption.

Conclusions

High levels of 2-AG appear to induce HFD preferences, and activate hypothalamic astrocytes via the cannabinoid system. We propose that there may be two distinct stages in the development of HFD preferences. The induction stage involves a transient increase in 2-AG, whereas the maintenance stage involves a long lasting increase in 2-AG levels and activation of astrocytes. Accordingly, hypothalamic 2-AG may influence the development of HFD preferences.

ADAMTS13 gene deletion enhances plasma high-mobility group box1 elevation and neuroinflammation in brain ischemia-reperfusion injury

Highly adhesive glycoprotein von Willebrand factor (VWF) multimer induces platelet aggregation and leukocyte tethering or extravasation on the injured vascular wall, contributing to microvascular plugging and inflammation in brain ischemia-reperfusion. A disintegrin and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) cleaves the VWF multimer strand and reduces its prothrombotic and proinflammatory functions. Although ADAMTS13 deficiency is known to amplify post-ischemic cerebral hypoperfusion, there is no report available on the effect of ADAMTS13 on inflammation after brain ischemia. We investigated if ADAMTS13 deficiency intensifies the increase of extracellular HMGB1, a hallmark of post-stroke inflammation, and exacerbates brain injury after ischemia-reperfusion. ADAMTS13 gene knockout (KO) and wild-type (WT) mice were subjected to 30-min middle cerebral artery occlusion (MCAO) and 23.5-h reperfusion under continuous monitoring of regional cerebral blood flow (rCBF). The infarct volume, plasma high-mobility group box1 (HMGB1) level, and immunoreactivity of the ischemic cerebral cortical tissue (double immunofluorescent labeling) against HMGB1/NeuN (neuron-specific nuclear protein) or HMGB1/MPO (myeloperoxidase) were estimated 24 h after MCAO. ADAMTS13KO mice had larger brain infarcts compared with WT 24 h after MCAO (p < 0.05). The rCBF during reperfusion decreased more in ADAMTS13KO mice. The plasma HMGB1 increased more in ADAMTS13KO mice than in WT after ischemia-reperfusion (p < 0.05). Brain ischemia induced more prominent activation of inflammatory cells co-expressing HMGB1 and MPO and more marked neuronal death in the cortical ischemic penumbra of ADAMTS13KO mice. ADAMTS13 deficiency may enhance systemic and brain inflammation associated with HMGB1 neurotoxicity, and aggravate brain damage in mice after brief focal ischemia. We hypothesize that ADAMTS13 protects brain from ischemia-reperfusion injury by regulating VWF-dependent inflammation as well as microvascular plugging.

The cannabinoid 1-receptor silent antagonist O-2050 attenuates preference for high-fat diet and activated astrocytes in mice

Endocannabinoids have been shown to activate reward-related feeding and to promote astrocytic differentiation. We investigated whether high-fat diet (HFD) intake produced a preference for HFD via an endocannabinoid-dependent mechanism. In the conditioned place preference test, the 2-week HFD-intake group showed preference for HFD and had increased expression of a marker for reactive astrocytes, glial fibrillary acid protein (GFAP), in the hypothalamus. The cannabinoid CB(1)-receptor antagonist O-2050 reduced the preference for HFD and expression of GFAP in the hypothalamus. These results suggested that HFD intake led to the development of a preference for HFD via astrocytic CB(1) receptors in the hypothalamus.

[Evaluation of the rewarding effects of drugs by conditioned place preference (CPP) paradigm: properties of volatile organic solvents and uncontrolled newly-abused drugs]

The conditioned place preference paradigm has been used to evaluate the motivational effects of drugs. The primary motivational effects of a drug are conditioned to prominent environmental stimuli of a conditioned place preference box, and after several conditionings, animals acquire secondary motivational effects of drugs. If the drug experience produces a positive effect, it is expected that animals will spend more time in the drug-paired place. This technique only requires that the animals carry out a simple operation to approach or avoid the drug-paired place. Place conditioning procedures have been used to assess rewarding and aversive properties of drugs. Abuse of volatile organic solvents among young people is a serious social issue in Japan. Organic solvents are cheap and relatively easy to obtain; hence, they carry the risk of becoming "gate-way drugs" for users. We developed an airtight conditioned place preference system for drug inhalation. Using this system, we found that toluene inhalation produced a rewarding effect in mice. The conditioned place preference paradigm has been used as a tool to delineate the neurochemical substrates mediating the rewarding effect of drugs. This method may be of great help in evaluating the abuse potential of substances (e.g., volatile organic solvents and uncontrolled newly-abused drugs) in animals.

Detection of amyloid beta protein in the urine of Alzheimer's disease patients and healthy individuals

To seek for a new valid biomarker using non-invasive specimens for the diagnosis of Alzheimer's disease (AD) and mild cognitive impairment (MCI), we carried out the detection of amyloid beta (Abeta) protein in urine. Ten-millilitre urine samples were first sedimented with trichloroacetic acid, and the pellets were resuspended for further analysis by Western blotting with anti-Abeta antibody. The detection sensitivity of the method was 40pg/ml. Rates of subjects positive for monomeric Abeta according to their clinical dementia rating (CDR) were 11.1% for CDR 0, 62.5% for CDR 0.5, 83.3% for CDR 1, 54.5% for CDR 2 and 0% for CDR 3. A single Abeta band relative to the CDR score reflects an alteration in the production, solubility and clearance of Abeta in the brain. Thus, the method could be used as both a diagnostic and monitoring tool in assessing AD and MCI patients during disease-modifying therapies.

Natural killer cells of Parkinson's disease patients are set up for activation: a possible role for innate immunity in the pathogenesis of this disease

Neuroinflammation in Parkinson's disease (PD) involves activation of microglia, participation of several inflammatory cytokines, prostaglandins, complement and systemic activation of natural killer (NK) cells, suggesting that innate immunity has a role in the pathogenesis of this disease. In this study, we examined NK activity and the expression of its regulatory molecules in peripheral lymphocytes of PD patients and compared the results with those of healthy controls. Expression of the inhibitory NKG2A receptors was significantly lower in PD, causing PD patients to be susceptible in a condition for NK activation after NK cells bind to target cells via these receptors.

Comparative study to elucidate the mechanism underlying the difference in airway hyperresponsiveness between two mouse strains

The mechanism underlying airway hyperresponsiveness (AHR), a characteristic feature of asthma, remains obscure. We attempted to elucidate the mechanism responsible for the different degrees of AHR in two mouse strains, BALB/c and C57BL/6, following exposure to an anaphylactic trigger. When ovalbumin (OVA)-sensitized mice were challenged daily with OVA for up to three consecutive days, the BALB/c mice showed a higher degree of airway responsiveness to methacholine than did C57BL/6. Following the OVA challenge, eosinophils and macrophages in bronchoalveolar lavage fluid (BALF) from BALB/c increased significantly in number compared to those from C57BL/6. BALB/c mice also exhibited a higher serum IgE level than that of C57BL/6 after OVA challenge. The enhanced AHR and eosinophilic infiltration in BALF were significantly reduced by pretreatment with a selective cysteinyl-leukotriene type 1 receptor (cysLT(1)R) antagonist, montelukast. In the in vitro study, cysLT production was significantly lower in the dissected lung tissue from BALB/c than in tissue from C57BL/6 when both groups were stimulated with saline. The lungs from BALB/c generated significantly larger amounts of cysLTs on incubation with OVA rather than with saline, while the lungs from C57BL/6 did not show any significant increase in cysLTs with antigen stimulation. Significant upregulation of cysLT(1)R and cysLT(2)R mRNA expression was induced by OVA challenge in the lungs of BALB/c, but not in those of C57BL/6. It is suggested that, after an anaphylactic reaction, the degree of AHR is dependent on the genetic background and that cysLTs play an important role in the mechanism involved.