Hyperglycemia increases SCO-spondin and Wnt5a secretion into the cerebrospinal fluid to regulate ependymal cell beating and glucose sensing.

Hyperglycemia increases glucose concentrations in the cerebrospinal fluid (CSF), activating glucose-sensing mechanisms and feeding behavior in the hypothalamus. Here, we discuss how hyperglycemia temporarily modifies ependymal cell ciliary beating to increase hypothalamic glucose sensing. A high level of glucose in the rat CSF stimulates glucose transporter 2 (GLUT2)-positive subcommissural organ (SCO) cells to release SCO-spondin into the dorsal third ventricle. Genetic inactivation of mice GLUT2 decreases hyperglycemia-induced SCO-spondin secretion. In addition, SCO cells secrete Wnt5a-positive vesicles; thus, Wnt5a and SCO-spondin are found at the apex of dorsal ependymal cilia to regulate ciliary beating. Frizzled-2 and ROR2 receptors, as well as specific proteoglycans, such as glypican/testican (essential for the interaction of Wnt5a with its receptors) and Cx43 coupling, were also analyzed in ependymal cells. Finally, we propose that the SCO-spondin/Wnt5a/Frizzled-2/Cx43 axis in ependymal cells regulates ciliary beating, a cyclic and adaptive signaling mechanism to control glucose sensing.

María Teresa Miras Portugal: a pioneer in the study of purinoceptors in chromaffin cells.

María Teresa Miras Portugal devoted most of her scientific life to the study of purinergic signalling. In an important part of her work, she used a model system: the chromaffin cells of the adrenal medulla. It was in these cells that she identified diadenosine polyphosphates, from which she proceeded to the study of adrenomedullary purinome: nucleotide synthesis and degradation, adenosine transport, nucleotide uptake into chromaffin granules, exocytotic release of nucleotides and autocrine regulation of chromaffin cell function via purinoceptors. This short review will focus on the current state of knowledge of the purinoceptors of adrenal chromaffin cells, a subject to which María Teresa made seminal contributions and which she continued to study until the end of her scientific life.

IQM-PC332, a Novel DREAM Ligand with Antinociceptive Effect on Peripheral Nerve Injury-Induced Pain.

Neuropathic pain is a form of chronic pain arising from damage of the neural cells that sense, transmit or process sensory information. Given its growing prevalence and common refractoriness to conventional analgesics, the development of new drugs with pain relief effects constitutes a prominent clinical need. In this respect, drugs that reduce activity of sensory neurons by modulating ion channels hold the promise to become effective analgesics. Here, we evaluated the mechanical antinociceptive effect of IQM-PC332, a novel ligand of the multifunctional protein downstream regulatory element antagonist modulator (DREAM) in rats subjected to chronic constriction injury of the sciatic nerve as a model of neuropathic pain. IQM-PC332 administered by intraplantar (0.01-10 µg) or intraperitoneal (0.02-1 µg/kg) injection reduced mechanical sensitivity by ≈100% of the maximum possible effect, with ED50 of 0.27 ± 0.05 µg and 0.09 ± 0.01 µg/kg, respectively. Perforated-patch whole-cell recordings in isolated dorsal root ganglion (DRG) neurons showed that IQM-PC332 (1 and 10 µM) reduced ionic currents through voltage-gated K+ channels responsible for A-type potassium currents, low, T-type, and high voltage-activated Ca2+ channels, and transient receptor potential vanilloid-1 (TRPV1) channels. Furthermore, IQM-PC332 (1 µM) reduced electrically evoked action potentials in DRG neurons from neuropathic animals. It is suggested that by modulating multiple DREAM-ion channel signaling complexes, IQM-PC332 may serve a lead compound of novel multimodal analgesics.

ß-Lactam TRPM8 Antagonist RGM8-51 Displays Antinociceptive Activity in Different Animal Models.

Transient receptor potential melastatin subtype 8 (TRPM8) is a cation channel extensively expressed in sensory neurons and implicated in different painful states. However, the effectiveness of TRPM8 modulators for pain relief is still a matter of discussion, since structurally diverse modulators lead to different results, depending on the animal pain model. In this work, we described the antinociceptive activity of a ß-lactam derivative, RGM8-51, showing good TRPM8 antagonist activity, and selectivity against related thermoTRP channels and other pain-mediating receptors. In primary cultures of rat dorsal root ganglion (DRG) neurons, RGM8-51 potently reduced menthol-evoked neuronal firing without affecting the major ion conductances responsible for action potential generation. This compound has in vivo antinociceptive activity in response to cold, in a mouse model of oxaliplatin-induced peripheral neuropathy. In addition, it reduces cold, mechanical and heat hypersensitivity in a rat model of neuropathic pain arising after chronic constriction of the sciatic nerve. Furthermore, RGM8-51 exhibits mechanical hypersensitivity-relieving activity, in a mouse model of NTG-induced hyperesthesia. Taken together, these preclinical results substantiate that this TRPM8 antagonist is a promising pharmacological tool to study TRPM8-related diseases.

The FGF2-induced tanycyte proliferation involves a connexin 43 hemichannel/purinergic-dependent pathway.

In the adult hypothalamus, the neuronal precursor role is attributed to the radial glia-like cells that line the third-ventricle (3V) wall called tanycytes. Under nutritional cues, including hypercaloric diets, tanycytes proliferate and differentiate into mature neurons that moderate body weight, suggesting that hypothalamic neurogenesis is an adaptive mechanism in response to metabolic changes. Previous studies have shown that the tanycyte glucosensing mechanism depends on connexin-43 hemichannels (Cx43 HCs), purine release, and increased intracellular free calcium ion concentration [(Ca2+ )i ] mediated by purinergic P2Y receptors. Since, Fibroblast Growth Factor 2 (FGF2) causes similar purinergic events in other cell types, we hypothesize that this pathway can be also activated by FGF2 in tanycytes to promote their proliferation. Here, we used bromodeoxyuridine (BrdU) incorporation to evaluate if FGF2-induced tanycyte cell division is sensitive to Cx43 HC inhibition in vitro and in vivo. Immunocytochemical analyses showed that cultured tanycytes maintain the expression of in situ markers. After FGF2 exposure, tanycytic Cx43 HCs opened, enabling release of ATP to the extracellular milieu. Moreover, application of external ATP was enough to induce their cell division, which could be suppressed by Cx43 HC or P2Y1-receptor inhibitors. Similarly, in vivo experiments performed on rats by continuous infusion of FGF2 and a Cx43 HC inhibitor into the 3V, demonstrated that FGF2-induced ß-tanycyte proliferation is sensitive to Cx43 HC blockade. Thus, FGF2 induced Cx43 HC opening, triggered purinergic signaling, and increased ß-tanycytes proliferation, highlighting some of the molecular mechanisms involved in the cell division response of tanycyte. This article has an Editorial Highlight see https://doi.org/10.1111/jnc.15218.

Nuclear magnetic resonance lipoproteins are associated with carotid atherosclerosis in type 1 diabetes and pre-eclampsia.

AIMS: Persistence of lipoprotein abnormalities in type 1 diabetes (T1D) and/or pre-eclampsia could be associated with cardiovascular disease (CVD). We assessed differences in the advanced lipoprotein profiles according to the presence of both conditions and their differential association with atherosclerosis. MATERIAL AND METHODS: We recruited 112 women without CVD and last pregnancy ≥5 years previously, divided into four groups (n = 28 per group): (a) T1D and previous pre-eclampsia; (b) T1D without pre-eclampsia; (c) pre-eclampsia without T1D; and (d) controls (without T1D/pre-eclampsia). Groups were matched by several risk factors, and diabetes duration and retinopathy in T1D. Carotid intima-media thickness (IMT) and the presence of plaque (IMT ≥1.5 mm) were assessed by ultrasonography. The lipoprotein profile was evaluated by nuclear magnetic resonance (NMR) spectroscopy. RESULTS: The participants were 44.9 ± 7.8 years old. Carotid plaque presence was 20.5%, with a higher prevalence in T1D and/or pre-eclampsia vs controls (P < .05). High-density lipoprotein (HDL)-related variables differed among groups, mainly driven by an increase in T1D (P < .05), whereas triglyceride-related variables were increased in pre-eclampsia [medium very low-density lipoprotein (VLDL) particles and triglyceride enrichment in HDL and low-density lipoprotein (LDL)]. Overall, in multivariate-adjusted models, LDL-related variables were the most strongly associated with atherosclerosis (P < .05). In age- and statin-adjusted models, previous pre-eclampsia showed an independent association with triglyceride-related variables (plaque: medium-VLDL-particles, OR 1.550 [1.013-2.374]; HDL-cholesterol/HDL-triglycerides ratio, OR 0.411 [0.175-0.967]). Regarding T1D, HDL-parameters were also differentially associated (maximum-IMT: HDL-cholesterol/HDL-particles ratio, ß = -.258, P = .036). CONCLUSIONS: NMR lipoproteins were differentially and independently associated with atherosclerosis in T1D/pre-eclampsia. Further studies are needed to ascertain the role of NMR parameters as CVD biomarkers in this high-risk population.

Novel glycoproteins identify preclinical atherosclerosis among women with previous preeclampsia regardless of type 1 diabetes status.

BACKGROUND AND AIMS: Information regarding inflammation and cardiovascular disease (CVD) risk in type 1 diabetes (T1D) or preeclampsia (PE) is scarce. We assessed differences in inflammation markers according to the presence of both conditions and their association with atherosclerosis. METHODS AND RESULTS: We recruited 112 women without CVD and last pregnancy ≥5 years previously (n = 28 per group): a)T1D and PE; b)T1D without PE; c)PE without T1D; and d)Controls (without T1D or PE). Groups were matched by several CVD risk factors, and diabetes duration and retinopathy in T1D. Carotid intima-media thickness (IMT) and plaque presence (IMT ≥1.5 mm) were assessed by ultrasonography. Inflammatory markers included classical variables (leucocytes and high-sensitivity C-reactive protein [hsCRP]) and glycoproteins by nuclear magnetic resonance (1H-NMR) spectroscopy (GlycA, GlycB, GlycF and the height/width [H/W] ratios of GlycA and GlycB). The age of the participants was 44.9 ± 7.8 years, and 20.5% harbored plaque. There were no differences in inflammatory markers among the four study groups. Overall, in multivariate-adjusted models, all 1H-NMR-glycoproteins (except GlycB) were positively associated with IMT measures (IMT of bulb and maximum-IMT of any carotid segment; p < 0.05). After dividing the sample according to PE status, previous findings remained largely unchanged. Furthermore, GlycF was independently associated with carotid plaque only in PE group (OR 5.08 [1.03-25.01] per 0.1 log-increments, p = 0.046). Neither leucocytes nor hsCRP were related to atherosclerosis. Regarding T1D status, non-uniform results were observed. CONCLUSIONS: High 1H-NMR-glycoprotein concentrations have a negative impact on carotid atherosclerosis among women with preeclampsia, regardless of T1D status.

Penicillin G Induces H+, K+-ATPase via a Nitric Oxide-Dependent Mechanism in the Rat Colonic Crypt.

BACKGROUND/AIMS: The colonic H+, K+ ATPase (HKA2) is a heterodimeric membrane protein that exchanges luminal K+ for intracellular H+ and is involved in maintaining potassium homeostasis. Under homeostatic conditions, the colonic HKA2 remains inactive, since most of the potassium is absorbed by the small intestine. In diarrheal states, potassium is secreted and compensatory potassium absorption becomes necessary. This study proposes a novel mechanism whereby the addition of penicillin G sodium salt (penG) to colonic crypts stimulates potassium uptake in the presence of intracellular nitric oxide (NO), under sodium-free (0-Na+) conditions. METHODS: Sprague Dawley rat colonic crypts were isolated and pHi changes were monitored through the ammonium prepulse technique. Increased proton extrusion in 0-Na+ conditions reflected heightened H+, K+ ATPase activity. Colonic crypts were exposed to penG, L-arginine (a NO precursor), and N-nitro l-arginine methyl ester (L-NAME, a NO synthase inhibitor). RESULTS: Isolated administration of penG significantly increased H+, K+ ATPase activity from baseline, p 0.0067. Co-administration of arginine and penG in 0-Na+ conditions further upregulated H+, K+ ATPase activity, p <0.0001. Crypt perfusion with L-NAME and penG demonstrated a significant reduction in H+, K+ ATPase activity, p 0.0058. CONCLUSION: Overall, acute exposure of colonic crypts to penG activates the H+, K+ ATPase in the presence of NO. This study provides new insights into colonic potassium homeostasis.

Higher risk of urinary tract infections in renal transplant recipients receiving pentamidine versus trimethoprim-sulfamethoxazole (TMP-SMX) for Pneumocystis pneumonia prophylaxis.

Urinary tract infection (UTI) is one of the most common infectious complications among renal transplant patients. Trimethoprim-sulfamethoxazole (TMP-SMX) is routinely used as first-line prophylaxis against Pneumocystis pneumonia (PCP) and other opportunistic infections including UTI. Aerosolized pentamidine is an alternate agent used for PCP prophylaxis; however, it does not provide coverage against uropathogens. This is a retrospective study of 81 renal transplant recipients who received TMP-SMX or aerosolized pentamidine for PCP prophylaxis at our center over 1 year. Survival analysis demonstrated increased cumulative incidence of UTI among patients receiving pentamidine for PCP prophylaxis compared to those receiving TMP-SMX (log-rank test P < .001). Univariate and multivariate Cox proportional hazard regression model showed pentamidine prophylaxis (HR 3.740; 95% CI 1.745-8.016; P = .001) and female sex (HR 4.025; 95% CI 1.770-9.154; P = .001) to independently increase UTI risk. Age, induction agent, graft type, diabetes, and delayed graft function (DGF) were not associated with increased risk. This study concludes that the use of pentamidine for PCP prophylaxis compared to TMP-SMX is associated with increased risk of UTI. Secondary UTI prophylaxis may be considered for patients who are unable to tolerate TMP-SMX and who have other risk factors for UTI; however, the efficacy of this has not been studied.

The Adrenal Medulla Modulates Mechanical Allodynia in a Rat Model of Neuropathic Pain.

We have investigated whether the stress response mediated by the adrenal medulla in rats subjected to chronic constriction injury of the sciatic nerve (CCI) modulates their nocifensive behavior. Treatment with SK29661 (300 mg/kg; intraperitoneal (I.P.)), a selective inhibitor of phenylethanolamine N-methyltransferase (PNMT) that converts noradrenaline (NA) into adrenaline (A), fully reverted mechanical allodynia in the injured hind paw without affecting mechanical sensitivity in the contralateral paw. The effect was fast and reversible and was associated with a decrease in the A to NA ratio (A/NA) in the adrenal gland and circulating blood, an A/NA that was elevated by CCI. 1,2,3,4-tetrahydroisoquinoline-7-sulfonamide (SKF29661) did not affect exocytosis evoked by Ca2+ entry as well as major ionic conductances (voltage-gated Na+, Ca2+, and K+ channels, nicotinic acetylcholine receptors) involved in stimulus-secretion coupling in chromaffin cells, suggesting that it acted by changing the relative content of the two adrenal catecholamines. Denervation of the adrenal medulla by surgical splanchnectomy attenuated mechanical allodynia in neuropathic animals, hence confirming the involvement of the adrenal medulla in the pathophysiology of the CCI model. Inhibition of PNMT appears to be an effective and probably safe way to modulate adrenal medulla activity and, in turn, to alleviate pain secondary to the injury of a peripheral nerve.

Overexpression of P2X3 and P2X7 Receptors and TRPV1 Channels in Adrenomedullary Chromaffin Cells in a Rat Model of Neuropathic Pain.

We have tested the hypothesis that neuropathic pain acting as a stressor drives functional plasticity in the sympathoadrenal system. The relation between neuropathic pain and adrenal medulla function was studied with behavioral, immunohistochemical and electrophysiological techniques in rats subjected to chronic constriction injury of the sciatic nerve. In slices of the adrenal gland from neuropathic animals, we have evidenced increased cholinergic innervation and spontaneous synaptic activity at the splanchnic nerve⁻chromaffin cell junction. Likewise, adrenomedullary chromaffin cells displayed enlarged acetylcholine-evoked currents with greater sensitivity to α-conotoxin RgIA, a selective blocker of α9 subunit-containing nicotinic acetylcholine receptors, as well as increased exocytosis triggered by voltage-activated Ca2+ entry. Altogether, these adaptations are expected to facilitate catecholamine output into the bloodstream. Last, but most intriguing, functional and immunohistochemical data indicate that P2X3 and P2X7 purinergic receptors and transient receptor potential vanilloid-1 (TRPV1) channels are overexpressed in chromaffin cells from neuropathic animals. These latter observations are reminiscent of molecular changes characteristic of peripheral sensitization of nociceptors following the lesion of a peripheral nerve, and suggest that similar phenomena can occur in other tissues, potentially contributing to behavioral manifestations of neuropathic pain.

Glial hypothalamic inhibition of GLUT2 expression alters satiety, impacting eating behavior.

Glucose is a key modulator of feeding behavior. By acting in peripheral tissues and in the central nervous system, it directly controls the secretion of hormones and neuropeptides and modulates the activity of the autonomic nervous system. GLUT2 is required for several glucoregulatory responses in the brain, including feeding behavior, and is localized in the hypothalamus and brainstem, which are the main centers that control this behavior. In the hypothalamus, GLUT2 has been detected in glial cells, known as tanycytes, which line the basal walls of the third ventricle (3V). This study aimed to clarify the role of GLUT2 expression in tanycytes in feeding behavior using 3V injections of an adenovirus encoding a shRNA against GLUT2 and the reporter EGFP (Ad-shGLUT2). Efficient in vivo GLUT2 knockdown in rat hypothalamic tissue was demonstrated by qPCR and Western blot analyses. Specificity of cell transduction in the hypothalamus and brainstem was evaluated by EGFP-fluorescence and immunohistochemistry, which showed EGFP expression specifically in ependymal cells, including tanycytes. The altered mRNA levels of both orexigenic and anorexigenic neuropeptides suggested a loss of response to increased glucose in the 3V. Feeding behavior analysis in the fasting-feeding transition revealed that GLUT2-knockdown rats had increased food intake and body weight, suggesting an inhibitory effect on satiety. Taken together, suppression of GLUT2 expression in tanycytes disrupted the hypothalamic glucosensing mechanism, which altered the feeding behavior.

Impact of TSH during the first trimester of pregnancy on obstetric and foetal complications: Usefulness of 2.5 mIU/L cut-off value.

OBJECTIVE: An association of pregnancy outcomes with subclinical hypothyroidism has been reported; however, there still exists a strong controversy regarding whether subclinical hypothyroidism ought to be dealt with or not. The objective of the study was to evaluate the association of foetal-maternal complications with first trimester maternal Thyrotropin (TSH) values. DESIGN: A retrospective study in a single tertiary care hospital was performed. PATIENTS: A total of 1981 pregnant women were studied during 2012. MEASUREMENTS: Thyrotropin (TSH) universal screening was performed between 9 and 12 weeks of gestation. Outcomes included foetal-maternal complications and newborn health parameters. RESULTS: Median TSH was 1.72 (0.99-2.61) mIU/L. The incidence of perinatal loss, miscarriage and stillbirth was 7.2%, 5.9% and 1.1%, respectively. Median TSH of women with and without miscarriage was 1.97 (1.29-3.28) vs 1.71 (0.96-2.58) mIU/L (P = .009). Incidence of pre-eclampsia was 3.2%; TSH in these women was 2.10 (1.40-2.74) vs 1.71 (0.98-2.59) mIU/L in those without (P = .027). TSH in women with dystocia in labour was 1.76 (1.00-2.53) vs 1.68 (0.94-2.59) mIU/L in those who gave birth with normal progression (P = .044). Women with TSH 2.5-5.1 mIU/L had a higher risk of perinatal loss [OR 1.589 (1.085-2.329)], miscarriage [OR 1.702 (1.126-2.572)] and premature birth [OR 1.39 (1.013-1.876)], adjusted by mother's age. There was no association with the other outcomes analysed. CONCLUSIONS: There is a positive association between maternal TSH in the first trimester of pregnancy and the incidence of perinatal loss and miscarriage. The TSH cut-off value of 2.5 mIU/L identified women with higher adverse pregnancy outcomes.

Factors influencing cardiometabolic risk profile in patients with psoriasis.

BACKGROUND: Psoriasis has been associated with metabolic syndrome and with an increased cardiovascular risk especially in patients with severe disease. The goal of this study was to estimate the prevalence of metabolic syndrome and other cardiovascular risk factors and its association with the psoriasis severity, sex and age. METHODS: Consecutive patients with psoriasis were enrolled in a prospective study over a 1-year period. Blood samples were collected. Psoriasis area and severity index (PASI) and body surface area scores and two dermatology quality of life (DQOL) questionnaires were used to evaluate psoriasis severity and the impact of the disease. RESULTS: Altogether 178 patients were included, of whom 44% had moderate-severe psoriasis. The overall prevalence of metabolic syndrome was 30% (men 34%, women 26%) without significant differences between patients with severe and mild disease. Age and menopause appeared to increase the risk for metabolic syndrome. Patients with severe psoriasis smoked more heavily, were more likely to have diabetes or insulin resistance and had higher homocysteine and lower high density lipoprotein cholesterol (HDL-C) levels than patients with mild psoriasis (P < 0.05). In women, a higher waist circumference was observed. Women had higher HDL-C levels and lower smoking and alcohol consumption rates. In accordance with the systematic coronary risk evaluation system, 18% of the patients had a high 10-year risk of fatal cardiovascular disease. CONCLUSIONS: Psoriasis severity was associated with diabetes, insulin-resistance, smoking habit and higher cardiovascular risk. Metabolic syndrome was related to age and menopause but not to psoriasis severity.

Necrotizing Enterocolitis and Growth in Preterm Infants Fed Predominantly Maternal Milk, Pasteurized Donor Milk, or Preterm Formula: A Retrospective Study.

Objective To evaluate the association between necrotizing enterocolitis (NEC), growth, and feeding. Methods This is a retrospective study of 551 infants (birth weight ≤ 1,500 g, ≤32 weeks' gestation). NEC, Bell's stage ≥ 2, was confirmed by independent review of sentinel radiographs. Feeding type was defined as ≥ 50% maternal milk (MM), pasteurized donor human milk (PDHM), or preterm formula (PF). Demographic and clinical characteristics including growth were compared between the three groups. Multivariable regression analysis was performed to control variables that differed in bivariate analysis. Results PDHM and PF mothers were more likely to be African-American, be enrolled in Medicaid, and have chorioamnionitis. PF mothers received antenatal steroids less frequently. NEC rates were different by feeding group (MM: 5.3%; PHDM: 4.3%; PF: 11.4%; p = 0.04). Adjusting for group differences, lower gestational age (adjusted odds ratio [aOR]: 0.85; 95% confidence interval [CI]: 0.74-0.97; p = 0.02], and PF (aOR: 2.53; 95% CI: 1.15-5.53; p = 0.02] were associated with NEC. There were no differences in other health outcomes or growth at hospital discharge. Conclusion MM and PDHM feedings, given until 34 weeks postmenstrual age, were associated with lower rates of NEC in very low birth weight infants without interfering with growth.

Role of endogenous hydrogen sulfide in nerve-evoked relaxation of pig terminal bronchioles.

Hydrogen sulfide (H2S) is a gasotransmitter employed for intra- and inter-cellular communication in almost all organ systems. This study investigates the role of endogenous H2S in nerve-evoked relaxation of pig terminal bronchioles with 260 µm medium internal lumen diameter. High expression of the H2S synthesis enzyme cystathionine γ-lyase (CSE) in the bronchiolar muscle layer and strong CSE-immunoreactivity within nerve fibers distributed along smooth muscle bundles were observed. Further, endogenous H2S generated in bronchiolar membranes was reduced by CSE inhibition. In contrast, cystathionine ß-synthase expression, another H2S synthesis enzyme, however was not consistently detected in the bronchiolar smooth muscle layer. Electrical field stimulation (EFS) and the H2S donor P-(4-methoxyphenyl)-P-4-morpholinylphosphinodithioic acid (GYY4137) evoked smooth muscle relaxation. Inhibition of CSE, nitric oxide (NO) synthase, soluble guanylyl cyclase (sGC) and of ATP-dependent K+, transient receptor potential A1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) channels reduced the EFS relaxation but failed to modify the GYY4137 response. Raising extracellular K+ concentration inhibited the GYY4137 relaxation. Large conductance Ca2+-activated K+ channel blockade reduced both EFS and GYY4137 responses. GYY4137 inhibited the contractions induced by histamine and reduced to a lesser extent the histamine-induced increases in intracellular [Ca2+]. These results suggest that relaxation induced by EFS in the pig terminal bronchioles partly involves the H2S/CSE pathway. H2S response is produced via NO/sGC-independent mechanisms involving K+ channels and intracellular Ca2+ desensitization-dependent pathways. Thus, based on our current results H2S donors might be useful as bronchodilator agents for the treatment of lung diseases with persistent airflow limitation, such as asthma and chronic obstructive lung disease.

Pre- and post-junctional bradykinin B2 receptors regulate smooth muscle tension to the pig intravesical ureter.

AIMS: Neuronal and non-neuronal bradykinin (BK) receptors regulate the contractility of the bladder urine outflow region. The current study investigates the role of BK receptors in the regulation of the smooth muscle contractility of the pig intravesical ureter. METHODS: Western blot and immunohistochemistry were used to show the expression of BK B1 and B2 receptors and myographs for isometric force recordings. RESULTS: B2 receptor expression was consistently detected in the intravesical ureter urothelium and smooth muscle layer, B1 expression was not detected where a strong B2 immunoreactivity was observed within nerve fibers among smooth muscle bundles. On ureteral strips basal tone, BK induced concentration-dependent contractions, were potently reduced by extracellular Ca(2+) removal and by B2 receptor and voltage-gated Ca(2+) (VOC) channel blockade. BK contraction did not change as a consequence of urothelium mechanical removal or cyclooxygenase and Rho-associated protein kinase inhibition. On 9,11-dideoxy-9a,11a-methanoepoxy prostaglandin F2α (U46619)-precontracted samples, under non-adrenergic non-cholinergic (NANC) and nitric oxide (NO)-independent NANC conditions, electrical field stimulation-elicited frequency-dependent relaxations which were reduced by B2 receptor blockade. Kallidin, a B1 receptor agonist, failed to increase preparation basal tension or to induce relaxation on U46619-induced tone. CONCLUSIONS: The present results suggest that BK produces contraction of pig intravesical ureter via smooth muscle B2 receptors coupled to extracellular Ca(2+) entry mainly via VOC (L-type) channels. Facilitatory neuronal B2 receptors modulating NO-dependent or independent NANC inhibitory neurotransmission are also demonstrated.

The role of tanycytes in hypothalamic glucosensing.

Tanycytes are elongated hypothalamic glial cells that cover the basal walls of the third ventricle; their apical regions contact the cerebrospinal fluid (CSF), and their processes reach hypothalamic neuronal nuclei that control the energy status of an organism. These nuclei maintain the balance between energy expenditure and intake, integrating several peripheral signals and triggering cellular responses that modify the feeding behaviour and peripheral glucose homeostasis. One of the most important and well-studied signals that control this process is glucose; however, the mechanism by which this molecule is sensed remains unknown. We along with others have proposed that tanycytes play a key role in this process, transducing changes in CSF glucose concentration to the neurons that control energy status. Recent studies have demonstrated the expression and function of monocarboxylate transporters and canonical pancreatic ß cell glucose sensing molecules, including glucose transporter 2 and glucokinase, in tanycytes. These and other data, which will be discussed in this review, suggest that hypothalamic glucosensing is mediated through a metabolic interaction between tanycytes and neurons through lactate. This article will summarize the recent evidence that supports the importance of tanycytes in hypothalamic glucosensing, and discuss the possible mechanisms involved in this process. Finally, it is important to highlight that a detailed analysis of this mechanism could represent an opportunity to understand the evolution of associated pathologies, including diabetes and obesity, and identify new candidates for therapeutic intervention.

Soluble TNFα-receptor 1 as a predictor of coronary calcifications in patients after long-term cure of Cushing's syndrome.

PURPOSE: Increased cardiovascular (CV) risk persists in Cushing's syndrome (CS), despite remission of hypercortisolism. The aim of this study was to evaluate prevalence of coronary artery disease in CS patients and its correlation with classical CV risk factors and inflammatory markers. METHODS: Cardiac multidetector computed tomography (MDCT) was performed in 41 patients (7 men, 31 of pituitary origin, 29 cured, mean age: 48.6 ± 13 years), using 64-slice Toshiba Aquilion systems. Coronary atherosclerotic plaques were detected and coronary calcifications quantified by the Agatston score (AS). Clinical and biochemical parameters were correlated with the AS to identify possible surrogate markers of coronary disease. Normal values for clinical and biochemical parameters were obtained from a gender- and age-matched normal reference population (n = 82). RESULTS: CS patients with calcifications (AS > 0) (N = 13, 32%) had higher levels of sTNF-R1, homocysteine, triglycerides, blood pressure and body mass index than patients without calcifications (AS = 0) and those of normal reference population. Both groups of CS patients (AS > 0 and AS = 0) had elevated trunk fat mass and IL-6 compared to reference values. Patients with AS > 0 had less adiponectin and higher insulin, HOMA and fibrinogen than those found in normal reference population. sTNF-R1 correlated positively with AS and remained significant after adjusting for confounding factors. The same result was observed when we considered only cured CS patients. CONCLUSION: In our cohort of CS patients sTNF-R1 was a predictor of coronary calcifications. Since MDCT is an expensive technique not readily available in daily clinical practice, increased sTNF-R1 could be a marker of CV risk even in cured CS.