Sleep-deprivation regulates α-2 adrenergic responses of rat hypocretin/orexin neurons

We recently demonstrated, in rat brain slices, that the usual excitation by noradrenaline (NA) of hypocretin/orexin (hcrt/orx) neurons was changed to an inhibition following sleep deprivation (SD). Here we describe that in control condition (CC), i.e. following 2 hours of natural sleep in the morning, the α(2)-adrenergic receptor (α(2)-AR) agonist, clonidine, had no effect on hcrt/orx neurons, whereas following 2 hours of SD (SDC), it hyperpolarized the neurons by activating G-protein-gated inwardly rectifying potassium (GIRK) channels. Since concentrations of clonidine up to a thousand times (100 μM) higher than those effective in SDC (100 nM), were completely ineffective in CC, a change in the availability of G-proteins is unlikely to explain the difference between the two conditions. To test whether the absence of effect of clonidine in CC could be due to a down-regulation of GIRK channels, we applied baclofen, a GABA(B) agonist known to also activate GIRK channels, and found that it hyperpolarized hcrt/orx neurons in that condition. Moreover, baclofen occluded the response to clonidine in SDC, indicating that absence of effect of clonidine in CC could not be attributed to down-regulation of GIRK channels. We finally tested whether α(2)-ARs were still available at the membrane in CC and found that clonidine could reduce calcium currents, indicating that α(2)-ARs associated with calcium channels remain available in that condition. Taken together, these results suggest that a pool of α(2)-ARs associated with GIRK channels is normally down-regulated (or desensitized) in hcrt/orx neurons to only become available for their inhibition following sleep deprivation.     

Landscape genetics and spatial pattern of phenotypic variation of Eristalis tenax across Europe

A study of population connectivity of the migratory insect species, such as dronefly Eristalis tenax (Diptera, Syrphidae), has an essential importance in understanding the relative influence of the evolutionary forces and environmental features that interact in the spatial distribution of molecular and morphological diversity. However, specific study aiming to understand spatial genetic structure of dronefly populations and its migratory potential is lacking. Hence, we studied a spatial pattern of genetic and phenotypic variation of seven European populations of E. tenax incorporating landscape genetic methods using allozyme data, wing size and shape and abdominal colour pattern. Based on the observed lack of genotypic structuring, we suggested that there has been sufficient long‐distance gene flow to effectively homogenize population structuring at a broader geographical scale. Wing shape similarity among populations and an overlap of abdominal colour variation showed no clear clustering related to geography, which is in congruence with genetic data. However, genetic (F_ST values) and phenotypic (wing size) data and landscape genetics indicated subdivision between the Balkan populations (four Serbian samples) and populations from Central (Germany and Switzerland) and Northern (Finland) Europe. These findings indicated a potential connection between the Central and Northern Europe supporting the Central European origin of the flies caught in Finland. Thus, by performing spatial analysis and combining genetic–morphological approach, we shed light on the movement pattern in complex landscapes and thus provided the necessary guidelines to a broad‐scale analysis of this widespread generalist pollinator.     

Beyond Bar and Line Graphs: Time for a New Data Presentation Paradigm

Figures in scientific publications are critically important because they often show the data supporting key findings. Our systematic review of research articles published in top physiology journals (n = 703) suggests that, as scientists, we urgently need to change our practices for presenting continuous data in small sample size studies. Papers rarely included scatterplots, box plots, and histograms that allow readers to critically evaluate continuous data. Most papers presented continuous data in bar and line graphs. This is problematic, as many different data distributions can lead to the same bar or line graph. The full data may suggest different conclusions from the summary statistics. We recommend training investigators in data presentation, encouraging a more complete presentation of data, and changing journal editorial policies. Investigators can quickly make univariate scatterplots for small sample size studies using our Excel templates.     

IL12RB2 Gene Is Associated with the Age of Type 1 Diabetes Onset in Croatian Family Trios

Background

Common complex diseases are influenced by both genetic and environmental factors. Many genetic factors overlap between various autoimmune diseases. The aim of the present study is to determine whether four genetic variants known to be risk variants for several autoimmune diseases could be associated with an increased susceptibility to type 1 diabetes mellitus.

Methods and Findings

We genotyped four genetic variants (rs2358817, rs1049550, rs6679356, rs9865818) within VTCN1, ANXA11, IL12RB2 and LPP genes respectively, in 265 T1DM family trios in Croatian population. We did not detect association of these polymorphisms with T1DM. However, quantitative transmission disequilibrium test (QTDT, orthogonal model) revealed a significant association between the age of onset of T1DM and IL12RB2 rs6679356 variant. An earlier onset of T1DM was associated with the rs6679356 minor dominant allele C (p = 0.005). The association remained significant even after the Bonferroni correction for multiple testing and permutation.

Conclusions

Variants originally associated with juvenile idiopathic arthritis (VTCN1 gene), sarcoidosis (ANXA11 gene), primary biliary cirrhosis (IL12RB2 gene) and celiac disease (LPP gene) were not associated with type 1 diabetes in our dataset. Nevertheless, association of IL12RB2 rs6679356 polymorphism with the age of T1DM onset suggests that this gene plays a role in defining the time of disease onset.     

Insulin administration in the mild hyperglycaemia changes expression of proinflammatory adhesion molecules on human aortic endothelial cells

An overexpression of cell adhesion molecules (CAMs) on the surface of endothelial cells is one of the first steps in a high glucose-mediated endothelial dysfunction in diabetic patients. The effect of insulin administration in the condition of elevated glucose concentration on the E-selectin, intracellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) expression on human aortic endothelial cells (HAEC) was investigated. Cells were cultured for 4 h in a medium supplemented with homocysteine (7 pM) and different concentration of glucose (5.5, 8.0, 12.0 and 16.5 mM respectively) with or without insulin (1 mlU/mL) addition. Expression of CAMs was analysed by flow-cytometry using monoclonal antibodies. Controls were CAMs expression in the medium with a corresponding glucose concentration. Obtained results show that short-term exposure of HAECs to moderate high glucose concentrations results in increased expression of E-selectin (2-fold), VCAM-1 (3-fold) and ICAM-1 (47%). At the same time, HAEC grown with 12 mM glucose expressed lesser E-selectin and, more ICAM-1 (for 64%) and VCAM-1 (41%) molecules. 16.5 mM glucose decreased expression of all investigated adhesion molecules. Addition of insulin was not changed expression of CAMs in a medium with 5.5 mM glucose. In conditions of elevated glucose concentration (12 mM), addition of insulin significantly dropped E-selectin (27%) and increased VCAM-1 (23%) expression. In conclusion, moderate elevated glucose concentration increased expression of cell adhesion molecules on HAEC. Insulin administration in the mild hyperglycaemia reduces an expression of the proinflammatory adhesion molecule E-selectin which could contribute in deceleration of macrovascular complications development in diabetic patients.     

Regulatory initiatives for natural latex allergy: US perspectives

The US Food and Drug Administration (FDA) has regulatory authority over foods, human drugs, cosmetics, medical devices, radiological products, biologics, and veterinary products. Among these products, FDA believes that the use of medical devices, including medical gloves, condoms, catheters, and breathing bags, represents the greatest source of natural latex proteins to exposed individuals. A medical device is defined in the Federal Food Drug and Cosmetic Act (FFDCA) as an instrument, apparatus, implement, machine, etc., that is intended for use in the diagnosis or treatment of disease or is intended to affect the structure or any function of the body of a human or other animal, and that does not achieve any of its principal intended purposes through chemical action in the body. This article provides some brief, general background about FDA's medical device regulatory process and then addresses the issue of natural latex allergy. Finally we discuss the steps the Agency has taken to evaluate the magnitude and nature of the problem, and FDA's efforts to assist manufacturers, health professionals, and others in minimizing exposure and sensitization to natural latex proteins in medical devices.     

Perforin expression after acute myocardial infarction--a pilot study

Perforin is an important mediator of inflammatory reactions. It is a quick-action cytotoxic mediator accumulated in the cytoplasmic granules of effector immunity cells (T lymphocytes, NK and NKT cells) which provide death signal in infected or transformed cells. Perforin-positive cells were previously detected in myocardial tissue during Trypanosoma cruzi infection and viral myocarditis while its role in chronic and progressive cardiovascular inflammatory disease such as atherosclerosis is almost completely unexplored. The perforin activity is also untested during acute coronary events that represent unexpected atherosclerotic complications due to the inflammatory destabilisation and atherosclerotic plaque rupture. The aim of this study was to investigate the presence of perforin, an important immunological inflammatory molecule in peripheral blood lymphocytes during the early period after acute myocardial infarction. We analyzed three subject groups: women with ST-segment elevation acute myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI), conservatively treated women with acute myocardial infarction without ST-segment elevation (NSTEMI) and a control group of healthy volunteers. The STEMI and NSTEMI groups did not basically differ in medication neither in levels of routine laboratory tests, while troponin I were significantly higher in the STEMI group. In the study, we detected an early decrease of perforin-positive lymphocytes in STEMI patients that were in contrast with their persisting elevation among NSTEMI patients. Despite greater myocardial necrosis in the STEMI group, results of this pilot-study indicated the prolonged perforin-mediated inflammatory response in patients with NSTEMI. This perforin down-regulation that follows the coronary interventional reperfusion in STEMI emphasized the possible anti-inflammatory role of primary PCI among patients with acute myocardial infarction. Given that the issue of routine primary PCI in NSTEMI is nowadays highly topical, the results we expect in the wake of this pilot study could demonstrate a significant impact on clinical practice. Further research is needed to confirm these results, compare the perforin-mediated activity to other inflammatory mediators in acute coronary events and to examine their impact on the long-term outcome.     

Neuropeptide Y modulates functions of inflammatory cells in the rat: distinct role for Y1, Y2 and Y5 receptors

Neuropeptide Y (NPY) has been reported to be a potent anti-inflammatory peptide with ability to directly modulate activity of granulocytes and macrophages. The present study aimed to correlate the effects of NPY in vivo on lipopolysaccharide-induced air-pouch exudates cells and in vitro on peripheral blood leukocytes functions. The role of different Y receptors was examined using NPY-related peptides and antagonists with diverse subtype specificity and selectivity for Y receptors. Y1, Y2 and Y5 receptors were detected on air-pouch exudates cells (flow cytometry) and peripheral blood granulocytes (immunocitochemistry). NPY in vivo reduced inflammatory cells accumulation into the air pouch, and decreased their adherence and phagocytic capacity via Y2/Y5 and Y1/Y2 receptors, respectively. Quite the opposite, NPY in vitro potentiated adhesiveness and phagocytosis of peripheral blood granulocytes and monocytes by activating Y1 receptor. The differences between in vivo and in vitro effects of NPY on rat inflammatory cells functions are mostly due to dipeptidyl peptidase 4 activity. In addition, suppressive effect of NPY in vivo is highly dependent on the local microenvironment, peptide truncation and specific Y receptors interplay.     

Progesterone Therapy,Endothelial Function and Cardiovascular Risk Factors: A 3-Month Randomized,Placebo-Controlled Trial in Healthy Early Postmenopausal Women

Background

Progesterone is effective treatment for hot flushes/night sweats. The cardiovascular effects of progesterone therapy are unknown but evidence suggests that premenopausal normal estradiol with also normal progesterone levels may provide later cardiovascular protection. We compared the effects of progesterone to placebo on endothelial function, weight, blood pressure, metabolism, lipids, inflammation and coagulation.

Methods and Results

We conducted a randomized, double-blind, 3-month placebo-controlled trial of progesterone (300 mg daily) among 133 healthy postmenopausal women in Vancouver, Canada from 2003–2009. Endothelial function by venous occlusion plethysmography was a planned primary outcome. Enrolled women were 1–11 y since last menstruation, not using hormones (for >6 months), non-smoking, without diabetes, hypertension, heart disease or their medications. Randomized (1∶1) women (55±4 years, body mass index 25±3) initially had normal blood pressure, fasting lipid, glucose and electrocardiogram results. Endothelial function (% forearm blood flow above saline) was not changed with progesterone (487±189%, n = 18) compared with placebo (408±278%, n = 16) (95% CI diff [−74 to 232], P = 0.30). Progesterone (n = 65) and placebo (n = 47) groups had similar changes in systolic and diastolic blood pressure, resting heart rate, weight, body mass index, waist circumference, total cholesterol, low-density lipoprotein cholesterol and triglyceride levels. High-density lipoprotein was lower (−0.14 mmol/L, P = 0.001) on progesterone compared with placebo. Fasting glucose, hs-C-reactive protein, albumin and D-dimer changes were all comparable to placebo. Framingham General Cardiovascular Risk Profile scores were initially low and remained low with progesterone therapy and not statistically different from placebo.

Conclusions

Results indicate that progesterone has short-term cardiovascular safety. Endothelial function, weight, blood pressure, waist circumference, inflammation and coagulation were unchanged as were lipids except for HDL-C. The statistically significant decrease in HDL-C levels was not clinically important (based on lack of Cardiovascular Risk Profile change).

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00152438","term_id":"NCT00152438"}}NCT00152438