Decreased inducibility of TNF expression in lipid-loaded macrophages

Background  

Inflammation and immune responses are considered to be very important in the pathogenesis of atherosclerosis. Lipid accumulation in macrophages of the arterial intima is a characteristic feature of atherosclerosis which can influence the inflammatory potential of macrophages. We studied the effects of lipid loading on the regulation of TNF expression in human monocyte-derived macrophages.     

The Effect of Small Variation of the Frequent Auditory Stimulus on the Event-Related Brain Potential to the Infrequent Stimulus

We investigated whether the mismatch process between a rare stimulus and the trace of frequent stimulus, which generates the mismatch-negativity component of the event-related potential, can tolerate a small variation in the intensity of the frequent stimulus. Series of short tone pips were presented to 10 subjects while they were reading a book and ignoring the auditory stimuli. The intensity (mean 80dB) of the frequent stimulus (600 Hz) varied within a range that was different in different blocks. The probability of the infrequent stimuli which were, in different blocks, either intensity deviants (600 Hz/70dB) or frequency deviants (650 Hz/80dB) was 10%. Both deviant stimuli elicited mismatch negativity even when the intensity of the frequent stimulus varied, although the amplitude of this component decreased with the increasing variability of the frequent stimulus. These results show that the generator process of mismatch negativity tolerates some variation in the repetitive stimulus, thus indicating that this process is also activated in ecologically more valid conditions. This is crucial to the interpretation of the generator process of mismatch negativity as a biologically vital warning mechanism.     

Studies in kidney tubulogenesis

Summary The formation of secretory tubules in the embryonic mouse metanephrogenic mesenchyme in vitro has been produced with embryonic spinal cord serving as inductor. The activity of NADH-tetrazolium reductase, acid phosphatase, thiamine pyrophosphatase and ATP-ase activities was assayed cytochemically on frozen sections of cold-formalin fixed explants.What was apparently the first phase of differentiation of kidney tubules became evident in the form of cell condensations. These were accompanied by an increased NADH-tetrazolium reductase activity, suggesting the maturation of both mitochondria (particulate reaction product) and endoplasmic reticulum (homogeneous staining). Furthermore, in the young explants there were visible areas of distinct enzyme activity, with no histological characteristics of the cell condensations. It was considered that these probably represented the earliest phase of differentiation detected by microscopic technique. Thiamine pyrophosphatase activity appeared in the Golgi apparatus of the cells during their organization into tubular epithelium and the formation of lumen. A subsequent increase in acid phosphatase activity of the cytoplasm was noticed. All of the active cytoplasmic organelles, marked by the enzyme activity cytochemically demonstrable, were moved to the apical side of the tubule cells in the course of their cytodifferentiation. After seven days of cultivation, the ATP-ase activity appeared first both in the cell membranes and in the cytoplasm of the tubule cells. At this phase of development, the kidney tubules induced in vitro thus displayed many of the cytochemical characteristics known to exist in the secretory tubules of the mature kidney.Supported by grant from the Sigrid Jusélius Foundation, by grant from Finnish Medical Research Council and by grant C-5347 from the National Cancer Institute, National Institutes of Health, Public Health Service to Prof. Toivonen and Dr. Saxén.     

Compromised duodenal mucosal integrity in children with short bowel syndrome after adaptation to enteral autonomy

BackgroundIntestinal adaptation has been extensively studied experimentally, but very limited data is available on human subjects. In this study we assessed intestinal adaption in humans with short bowel syndrome (SBS).MethodsWe comparatively evaluated mucosal hyperplasia, inflammation, barrier function and nutrient transport using histology, immunohistochemistry and qPCR for selected 52 key genes in duodenal biopsies obtained from children with SBS after weaning off parenteral nutrition (n = 33), and matched controls without intestinal pathology (n = 12). Small bowel dilatation was assessed from contrast small bowel series.ResultsDuodenal mucosa of SBS children showed increased histologic inflammation of lamina propria (p = 0.033) and mucosal mRNA expression of tumor necrosis factor (p = 0.027), transforming growth factor (TGF)-β2 (p = 0.006) and caveolin-1 (CAV1; p = 0.001). Villus height, crypt depth, enterocyte proliferation, apoptosis and expression of proliferation and nutrient transport genes remained unchanged. Pathologic small bowel dilatation reduced crypt depth (p = 0.045) and downregulated mRNA expression of interleukin (IL)-6 by three-fold (p = 0.008), while correlating negatively with IL6 (r = -0.609, p = 0.004). Loss of ileocecal valve (ICV) upregulated mRNA expression of toll-like receptor 4 (TLR4), TGF-β1, CAV1, several apoptosis regulating genes, and mRNA expression of zonulin (p < 0.05 for all).ConclusionsDespite successful adaptation to enteral autonomy, duodenal mucosa of SBS children displayed histologic and molecular signs of abnormal inflammation and regulation of epithelial permeability, whereas no structural or molecular signs of adaptive hyperplasia or enhanced nutrient transport were observed. Excessive dilatation of the remaining small bowel paralleled impaired duodenal crypt homeostasis, while absence of ICV modified regulation of mucosal inflammation, regeneration and permeability.Level of evidenceII     

Meta-analysis of epigenome-wide association studies of carotid intima-media thickness

Common carotid intima-media thickness (cIMT) is an index of subclinical atherosclerosis that is associated with ischemic stroke and coronary artery disease (CAD). We undertook a cross-sectional epigenome-wide association study (EWAS) of measures of cIMT in 6400 individuals. Mendelian randomization analysis was applied to investigate the potential causal role of DNA methylation in the link between atherosclerotic cardiovascular risk factors and cIMT or clinical cardiovascular disease. The CpG site cg05575921 was associated with cIMT (beta?=??0.0264, p value?=?3.5?×?10^–8) in the discovery panel and was replicated in replication panel (beta?=??0.07, p value?=?0.005). This CpG is located at chr5:81649347 in the intron 3 of the aryl hydrocarbon receptor repressor gene (AHRR). Our results indicate that DNA methylation at cg05575921 might be in the pathway between smoking, cIMT and stroke. Moreover, in a region-based analysis, 34 differentially methylated regions (DMRs) were identified of which a DMR upstream of ALOX12 showed the strongest association with cIMT (p value?=?1.4?×?10^–13). In conclusion, our study suggests that DNA methylation may play a role in the link between cardiovascular risk factors, cIMT and clinical cardiovascular disease.

     

Up-regulation of β1-adrenergic receptors in rat brain after chronic citalopram and fluoxetine treatments

Quantitative receptor autoradiography was used to study the effects of the selective serotonin reuptake inhibitors citalopram and fluoxetine and the tricyclic antidepressant imipramine on the regulation of ₁-adrenergic receptors in the rat brain. Rats were treated with saline, citalopram (10 mg kg^–1), fluoxetine (10 mg kg^–1), or imipramine (15 mg kg^–1) SC once daily for 14 days. [¹²⁵I]Iodocyanopindolol binding to ₁-adrenergic receptors was found to increase significantly in the caudate-putamen and the somatosensory areas of the frontal cortex after both citalopram and fluoxetine treatments. Imipramine treatment elicited a marked decrease in ₁ binding in the outer laminae of the cingulate cortex, as well as in the motor and somatosensory areas of the frontal cortex. In a separate experiment, rats were treated with saline, citalopram (2.5, 10 and 20 mg kg^–1) or fluoxetine (2.5, 10 and 20 mg kg^–1) SC once daily for 14 days. The effects of citalopram and fluoxetine on ₁ receptors in the somatosensory cortex and caudate-putamen were replicated. These results demonstrate that chronic administration of selective serotonin reuptake inhibitors, in contrast to imipramine, can cause a regional up-regulation of ₁-adrenergic receptors in the rat brain.     

TCDD-induced anorexia and wasting syndrome in rats: effects of diet-induced obesity and nutrition

Interactions of diet and diet-induced obesity, and the characteristic wasting syndrome caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were studied in TCDD-resistant Han/Wistar and TCDD-sensitive Long-Evans rats. The rats were made obese by feeding them either a high-energy diet (consisting of chocolate, cheese, and chow) or force feeding. TCDD reduced body weight in a parallel manner in lean and obese rats. The high-energy diet diminished the body weight loss and increased the survival time in L-E rats after a lethal dose of TCDD, while energy supplement with high-fat/low-protein food had an opposite effect. In conclusion, diet-induced obesity and TCDD had additive effects on body weight. Dietary manipulations were able to modify the weight loss and survival time after TCDD. Fat seems to have a negative impact, while carbohydrate or protein may have a positive impact in this respect. The results are in agreement with a view that TCDD-exposed rats have a negative fat balance favoring fat loss.