Angiopoietin-2-induced lymphatic endothelial cell migration drives lymphangiogenesis via the β1 integrin-RhoA-formin axis

Lymphangiogenesis is an essential physiological process but also a determining factor in vascular-related pathological conditions. Angiopoietin-2 (Ang2) plays an important role in lymphatic vascular development and function and its upregulation has been reported in several vascular-related diseases, including cancer. Given the established role of the small GTPase RhoA on cytoskeleton-dependent endothelial functions, we investigated the relationship between RhoA and Ang2-induced cellular activities. This study shows that Ang2-driven human dermal lymphatic endothelial cell migration depends on RhoA. We demonstrate that Ang2-induced migration is independent of the Tie receptors, but dependent on β1 integrin-mediated RhoA activation with knockdown, pharmacological approaches, and protein sequencing experiments. Although the key proteins downstream of RhoA, Rho kinase (ROCK) and myosin light chain, were activated, blockade of ROCK did not abrogate the Ang2-driven migratory effect. However, formins, an alternative target of RhoA, were identified as key players, and especially FHOD1. The Ang2-RhoA relationship was explored in vivo, where lymphatic endothelial RhoA deficiency blocked Ang2-induced lymphangiogenesis, highlighting RhoA as an important target for anti-lymphangiogenic treatments.

     

The effect of hyperthyroidism and hypothyroidism on alpha 1- and alpha 2-adrenergic responsiveness in rat aortic smooth muscle

We report the role of thyroid hormones on in vitro responsiveness of rat aortic smooth muscle to alpha-adrenergic stimulation. Four groups of rats: hypothyroid, hyperthyroid, thyroxine (0.1 mg/kg) treated hypothyroid and controls were employed. Response of alpha 1- and alpha 2-adrenoceptors was evoked with 6 incremental doses (10(-9) to 10(-4) M) of preferential alpha 1-agonist, phenylephrine and alpha 2-agonist, clonidine respectively. alpha 1-Adrenoceptors were also evoked by phenylephrine after blockade of alpha 2-adrenoceptors with 10(-7) M yohimbine. Similarly, alpha 2-adrenoceptors were stimulated with clonidine after blocking alpha 1-adrenoceptors with selective antagonists prazosin (10(-7) M). Aortic responsiveness to alpha-agonist norepinephrine was compared between the aortae of hypothyroid and euthyroid rats after blockade of alpha 2-adrenoceptors with 10(-4) M corynanthine. We report that in hypothyroid aortae, alpha 1-adrenergic response was significantly decreased, the dose response curve shifted to the right and the maximal response was 30% less than the normal; alpha 2-adrenergic response was completely inhibited in hypothyroid state; also, IP injections of 0.1 mg/kg thyroxine twice in 48 h to thyroidectomized rats reversed the effects of hypothyroidism on both alpha 1- and alpha 2-adrenergic response. Hyperthyroidism did not alter alpha 1- and alpha 2-adrenergic response. These results signify the role of thyroid hormones in the regulation of alpha-adrenergic response in rat aortae.     

Cardiovascular and hemodynamic effect of polyethylene glycol in Rats

BACKGROUND: Polyethylene Glycol (PEG) is a solvent and used in a wide range of biomedical applications. Many fatty-acid-based molecules cannot be administered without a solvent in vivo. PEG can be used to dissolve compounds to make them water soluble. However, the effect of PEG on the cardiovascular system has not been studied. In this study, we evaluated the effect of PEG on the cardiovascular system in rat models. METHODS: Twenty male Sprague-Dawley rats weighing 250-300 g were used in this study. The control group (10 rats) were injected intraperitoneally with 0.5 ml of 5% D/W in normal saline and the second group (10 rats) with PEG 400, 2 ml/kg ip, twice a day for 1 week. After 4 weeks, the rats underwent general anesthesia and a 1.4 French ultra miniature pressure volume catheter (Millar catheter) was placed in the left ventricle via the right carotid artery to measure comprehensive hemodynamic data. The data were analyzed with PVAN pressure-volume analysis software. RESULTS: All the systolic and diastolic parameters were similar in both groups except for the effective arterial elastance (Ea), which was decreased in the PEG group. There were no significant differences in maximum (dp/dt(max)) and minimum (dp/dt(min)) development of pressure stroke work, cardiac output, ejection fraction, end systolic volume (Ves), and end diastolic volume. CONCLUSIONS: We have demonstrated that PEG, as a solvent, decreases Ea in rats in comparison to a placebo. Therefore, PEG as a solvent should be used cautiously in the cardiovascular research.     

In vitro caffeine induced aortic smooth muscle reactivity in rat

The effects of caffeine on aortic smooth muscle contractility during hypertension were studied in SHR and WKY control rats. To compare the effects of Mg++ on vascular reactivity induced by caffeine 1.2 mM MgCl2 was either included or omitted from the Krebs solution bathing the aortic tissue. The role of alpha-adrenergic receptors and verapamil-sensitive Ca++ channels in eliciting caffeine induced contraction in aortic tissues was also examined in Sprague Dawley rats. We report that the aortic smooth muscle from SHR animal was less responsive than WKY aortic smooth muscle to 10 and 20 mM concentrations of caffeine. Caffeine induced a relaxation of aortic smooth muscle contracted with 60 mM KCl or 10(-7) M NE. However, the relaxation response was slower in SHR as compared to WKY rats. To assess the involvement of alpha-adrenergic receptors in caffeine induced aortic contractility alpha 1- and alpha 2-receptors were blocked with 10(-7) M prazosin and 10(-7) M yohimbine respectively. The caffeine induced aortic contractility did not seem to involve alpha-adrenergic receptors. A blockade of verapamil sensitive Ca++ channels with 10(-7) M verapamil failed to inhibit caffeine induced aortic contractility. These results indicate that caffeine involves release of Ca++ in vascular muscle, however, Ca++ is released from a site other than the one controlled by alpha-adrenergic receptors. Also, the Ca++ channels involved are other than the Verapamil sensitive Ca++ channels. Yet it is clear that if the aortic contractility is due to Ca++ release alone, then caffeine is a potent agent for Ca++ release in the aortic smooth muscle of rat. Additionally, the caffeine-sensitive mechanism for aortic smooth muscle contraction is impaired during hypertension.     

Coronary artery disease is associated with the ratio of apolipoprotein A-I/B and serum concentration of apolipoprotein B, but not with paraoxonase enzyme activity in Iranian subjects

To determine the association of serum apolipoprotein (apo) A-I and B concentrations, and paraoxonase (PON) high-density lipoprotein (HDL) associated enzyme activity with angiographically determined coronary artery disease (CAD) in Iranian diabetic and non-diabetic CAD patients and non-diabetic control subjects, 251 subjects aged 30-70 years, who underwent their first coronary angiography were matched and randomly assigned into three groups: CAD(+)DM(+), CAD(+)DM(-), and CAD(-)DM(-) (control). Stenosis of > or =50% in one or more coronary arteries was classified as CAD(+). CAD(-) was defined as a maximum stenosis of 10% in any coronary artery. Fasting serum concentrations of cholesterol (TC), triglycerides (TGs), LDL-C, HDL-C, apo A-I/B and PON activity were determined. Apolipoprotein concentrations were measured in a fasting serum sample by immunoturbidometric assay and paraoxonase/arylesterase activities by spectrophotometric assay of p-nitrophenol/phenol production following addition of paraoxon/phenylacetate. Information concerning non-lipid risk factors were collected by questionnaires. No significant difference was observed in HDL-C, LDL-C, apo A-I, and PON/arylesterase activity between the study groups. The values of TC (213+/-38 vs 196+/-45, P<0.05), TGs (209+/-187 vs 151+/-113, P<0.01), apo B (99+/-22 vs 96+/-24, P<0.0001), TC/HDL-C (4.8+/-1.5 vs 4.0+/-1.3, P<0.001) and LDL-C/HDL-C (2.9+/-1.1 vs 2.4+/-1.1, P<0.05) were higher and apo A-I/B (1.7+/-0.4 vs 2.0+/-0.6, P<0.01) was lower in CAD(+)DM(+) patients than in control subjects. In CAD(+)DM(-) group, only the level of apo B (96+/-24 vs 85+/-18, P<0.01), and the ratio of apo A-I/B (1.8+/-0.4 vs 2.0+/-0.6, P<0.01), were significantly higher than those of control group. On multiple logistic regression analysis, the best markers for discrimination between CAD(+) groups and CAD(-) control subjects were the ratio of apo A-I/B in diabetic and apo B in non-diabetic patients. The results suggest that in Iranian diabetic and non-diabetic patients with CAD the concentration of apolipoproteins are better markers than traditional lipid parameters in discriminating between CAD(+) and CAD(-) subjects. Lack of significant difference in PON activity between CAD patients and CAD(-) controls supports the concept of interethnic variability in PON polymorphism and unimodal distribution of its activity in non-Europid populations observed in other studies.     

Respiratory Flow–Sound Relationship During Both Wakefulness and Sleep and Its Variation in Relation to Sleep Apnea

Tracheal respiratory sound analysis is a simple and non-invasive way to study the pathophysiology of the upper airway and has recently been used for acoustic estimation of respiratory flow and sleep apnea diagnosis. However in none of the previous studies was the respiratory flow–sound relationship studied in people with obstructive sleep apnea (OSA), nor during sleep. In this study, we recorded tracheal sound, respiratory flow, and head position from eight non-OSA and 10 OSA individuals during sleep and wakefulness. We compared the flow–sound relationship and variations in model parameters from wakefulness to sleep within and between the two groups. The results show that during both wakefulness and sleep, flow–sound relationship follows a power law but with different parameters. Furthermore, the variations in model parameters may be representative of the OSA pathology. The other objective of this study was to examine the accuracy of respiratory flow estimation algorithms during sleep: we investigated two approaches for calibrating the model parameters using the known data recorded during either wakefulness or sleep. The results show that the acoustical respiratory flow estimation parameters change from wakefulness to sleep. Therefore, if the model is calibrated using wakefulness data, although the estimated respiratory flow follows the relative variations of the real flow, the quantitative flow estimation error would be high during sleep. On the other hand, when the calibration parameters are extracted from tracheal sound and respiratory flow recordings during sleep, the respiratory flow estimation error is less than 10%.     

Serum Levels of IL-6, IL-10, IL-12, IL-17 and IFN-γ and Their Association with Markers of Bone Metabolism in Vitamin D-Deficient Female Students

Different studies have shown the regulatory effects of vitamin D₃ on the immune system and bone metabolism. Regarding the effects of vitamin D on immune cells and the importance of cytokines on bone metabolism, we assessed the association between serum levels of interleukin (IL)-6, IL-10, IL-12, IL-17 and IFN-γ cytokines and bone metabolism markers (Ca, P, PTH, ALP) in female students with vitamin D deficiency compared with control group. A total of 100 subjects with 25-hydroxy vitamin D₃ (25-(OH) D₃) deficiency were selected as case and 100 subjects with sufficient 25-hydroxy vitamin D₃ (25-(OH) D₃) were selected as the control group. The serum levels of IL-6, IL-10, IL-12, IL-17 and IFN-γ were measured by ELISA method. Ionized Ca, PTH, P, ALP levels were also determined in all participants. The results showed a statistically significant positive correlation between the levels of ALP with IFN-γ, PTH with IL-17 and a significant negative correlation between P with IL-10 in vitamin D deficient group. The results suggest that IL-17, IFN-γ and IL-10 are important mediators of bone metabolism and vitamin D affect bone metabolism, at least in part, through immune system. In addition, not only vitamin D affect bone metabolism but also modulates immune responses.     

Snoring sounds variability as a signature of obstructive sleep apnea

Snoring sounds vary significantly within and between snorers. In this study, the variation of snoring sounds and its association with obstructive sleep apnea (OSA) are quantified. Snoring sounds of 42 snorers with different degrees of obstructive sleep apnea and 15 non-OSA snorers were analyzed. The sounds were recorded by a microphone placed over the suprasternal notch of trachea, simultaneously with polysomnography (PSG) data over the entire night. We hypothesize that snoring sounds vary significantly within a subject depending on the level of obstruction, and thus the level of airflow. We also hypothesize that this variability is associated with the severity of OSA. For each individual, we extracted snoring sound segments from the respiratory recordings, and divided them into three classes: non-apneic, hypopneic, and post-apneic using their PSG information. Several features were extracted from the snoring sound segments, and compared using a nonparametric statistical test. The results show significant shift in the median of features among the snoring sound classes (p < 0.00001) of an individual. In contrast to hypopneic and post-apneic classes, the characteristics of snoring sounds did not vary significantly over time in non-apneic class. Therefore, we used the total variation norm of each subject to classify the participants as OSA and non-OSA snorers. The results showed 92.9% sensitivity, 100% specificity and 96.4% accuracy.     

Histological and mucin histochemical study of the small intestine of the Persian squirrel (Sciurus anomalus)

This article describes the histological and mucin histochemical properties of the small intestine of the Persian squirrel (Sciurus anomalus). This species is widely distributed in the Middle East and can be found as a companion animal. The histological studies revealed that the plicae circulares were not visible in the tunica mucosa. The maximum height and width of the villi were observed in the duodenum, which then decreased toward the ileum. The muscularis mucosa was scattered, whereas the tunica submucosa was composed of dense connective tissue. The lymphatic nodules were seen in the submucosa of the distal part of the jejunum and ileum, and Brunner’s glands were embedded in the initial portion of the duodenum. The tunica muscularis was significantly thicker in the ileum, and the circular muscle layer was thicker than the longitudinal muscle layer throughout the entire length of the small intestine. The mucin histochemistry, which was examined using the periodic acid-Schiff (PAS) and alcian blue (AB) (pH 1.0 and 2.5) and also PAS–AB (pH 2.5) and aldehyde fuchsin-AB (pH 2.5) techniques coupled with methylation and saponification reaction for some sections, showed that the small intestine mucous content included both carboxylated and sulfated acidic mucins with few neutral mucins. The results of this study contribute to the knowledge of the histological and histochemical characteristics of the gastrointestinal tracts of exotic mammals and provide data for comparison with other mammals.