Emerging roles of non-coding RNAs in pancreatic β-cell function and dysfunction.

Pancreatic β-cells play a central role in glucose homeostasis by tightly regulating insulin release according to the organism's demand. Impairment of β-cell function due to hostile environment, such as hyperglycaemia and hyperlipidaemia, or due to autoimmune destruction of β-cells, results in diabetes onset. Both environmental factors and genetic predisposition are known to be involved in the development of the disease, but the exact mechanisms leading to β-cell dysfunction and death remain to be characterized. Non-coding RNA molecules, such as microRNAs (miRNAs), have been suggested to be necessary for proper β-cell development and function. The present review aims at summarizing the most recent findings about the role of non-coding RNAs in the control of β-cell functions and their involvement in diabetes. We will also provide a perspective view of the future research directions in the field of non-coding RNAs. In particular, we will discuss the implications for diabetes research of the discovery of a new communication mechanism based on cell-to-cell miRNA transfer. Moreover, we will highlight the emerging interconnections between miRNAs and epigenetics and the possible role of long non-coding RNAs in the control of β-cell activities.

Fluorescence of the bladder washout fluid following cystoscopy: a preliminary study

During fluorescence cystoscopy, it is observed that the acquired images are sometimes blurred by a greenish background originating from the bladder washout fluid. Several fluorophores are involved in this overall liquid fluorescence, and their exact origin and relative contributions remain unknown. In this study, the bladder washout fluid is sampled at different times during fluorescence cystoscopy examinations. In total, 32 samples from 12 patients are analyzed with a spectrofluorimeter (excitation range: 350-445 nm, emission range 380-700 nm). This study shows clearly that the position of the fluorescence peaks (excitation/emission wavelengths: 450/525 nm, 405/625 nm) and shoulder (440/525 nm) is reproducible between different patients. It also suggests that an excitation at wavelengths higher than 400 nm helps to suppress this solution background fluorescence. Additionally, the pH of the solution seems to influence the position of the fluorescence peaks, and this suggests that changing the pH of the examination liquid could help in avoiding the greenish background.

Compressed collagen gel: a novel scaffold for human bladder cells.

Collagen is highly conserved across species and has been used extensively for tissue regeneration; however, its mechanical properties are limited. A recent advance using plastic compression of collagen gels to achieve much higher concentrations significantly increases its mechanical properties at the neo-tissue level. This controlled, cell-independent process allows the engineering of biomimetic scaffolds. We have evaluated plastic compressed collagen scaffolds seeded with human bladder smooth muscle cells inside and urothelial cells on the gel surface for potential urological applications. Bladder smooth muscle and urothelial cells were visualized using scanning electron microscopy, conventional histology and immunohistochemistry; cell viability and proliferation were also quantified for 14 days in vitro. Both cell types tested proliferated on the construct surface, forming dense cell layers after 2 weeks. However, smooth muscle cells seeded within the construct, assessed with the Alamar blue assay, showed lower proliferation. Cellular distribution within the construct was also evaluated, using confocal microscopy. After 14 days of in vitro culture, 30% of the smooth muscle cells were found on the construct surface compared to 0% at day 1. Our results provide some evidence that cell-seeded plastic compressed collagen has significant potential for bladder tissue regeneration, as these materials allow efficient cell seeding inside the construct as well as cell proliferation.

Implication of Nerve Growth Factor in intestinal mucosal mast cell activity and colonic motor alterations in a model of ovalbumin-induced gut dysfunction in rats

We determined NGF involvement in MMCs and colonic motor alterations in an ovalbumin (OVA)-induced gut dysfunction model in rats. Animals received OVA (6 weeks), with/without simultaneous K252a (TrkA antagonist) treatment. MMCs, rat mast cell protease II (RMCPII) levels and colonic contractility in vitro were assessed. OVA increased MMC density and RMCPII concentration. Spontaneous contractility was similar in both groups and inhibited by K252a. Carbachol responses were increased by OVA in a K252a-independent manner. NO-synthase inhibition increased spontaneous activity in OVA-treated animals in a K252a-dependent manner. These observations support an involvement of NGF in the functional changes observed in this model.

Immune Dysfunction and the Pathogenesis of AIDS-associated non-Hodgkin's Lymphoma

Much has been learned about how HIV-induced immune dysfunction contributes to B cell hyperactivation, and potentially, to the pathogenesis of AIDS-lymphoma. However, further studies are needed to fully understand how HIV infection and immune dysfunction promote B cell hyperactivation and the development/growth of AIDS-lymphoma. In particular, studies are needed to define the role of HHV8 vIL6, IL6 receptor-expression, and lymphocyte surface stimulatory molecules, in promoting B cell hyperactivation or lymphoma cell growth.

On the function of proton-gated ion channels ASICs and TRPV1 : a patch-clamp study

AbstractAcidosis is encountered during tissue inflammation and triggers pain in humans. H+-gated ion channels are expressed at high levels in sensory neurons of the peripheral nervous system. Ion channels from two different families present the required pH sensitivity to detect the acidosis associated with peripheral inflammation: Acid-Sensing Ion Channels (ASICs) and the Transient Receptor Potential Vanilloid-1 (TRPV1) channel.ASICs are members of the Degenerin/Epithelial Na+ Channel family of ion channels. Six ASIC subunits have been identified in mammals (ASICla, -lb, -2a, -2b, -3 and -4). ASICs form In-activated voltage-insensitive homo- or heterotrimeric Na+ channels. TRPV1 is a member of the TRP family of ion channels and forms non-selective cation channels that mediate a sustained current. TRPV1 is activated by H+, heat (T>43°C), lipids, capsaicin, voltage and other stimuli. A stimulus can increase TRPV1 response to a different stimulus. For example H+ can shift the capsaicin concentration dependence of TRPV1 to lower values. ASICs and TRPV1 have been shown to be involved in inflammatory pain. Using the patch-clamp technique, we studied different aspects of the function of ASICs and TRPV1 in the physiological context of pain.In the first part of this thesis, we characterize the effect of a temperature increase from 25 to 35°C on the function of ASICs and TRPV1 in transfected CHO cells and primary cultures of rat DRG sensory neurons. ASICs give rise to transient currents while TRPV1 mediates a sustained current. In addition, ASICs and TRPV1 respond to H+ with distinct pH dependences. We assess the relative contribution of ASICs and TRPV1 to H+-evoked electrical signaling in rat DRG neurons and we conclude that ASICs are the most important pH sensors in the pH range 7.4 to 6.0 at 35°C in sensory neurons.ASICs and TRPV1 are expressed in the epithelium lining the lumen of the bladder (urothelium). The Bladder Pain Syndrome/Interstitial Cystitis (BPS/IC) is a painful condition associated with a dysfunction of the urothelial barrier and with inflammation. In the second part of this thesis, we show that human urothelial cells -the cell line TEU2 and primary cultures of human bladder urothelium- express functional ASICs but no functional TRPV1 channels. In addition, we show that the levels of ASIC2 and ASIC3 mRNA are increased in the urothelium of patients suffering from BPS/IC. These data suggest that ASICs are involved in the pathology of BPS/IC.Finally, we demonstrate that APETx2 inhibits the sensory neuron specific voltage-dependent Na+ channel Nav1.8. APETx2 was previously shown to inhibit homo- or heterotrimeric ASIC3- containing channels with IC5o from 0.08 to 1 μΜ. We show that APETx2 also inhibits Nav1.8 with an ICsoof «2.6 μΜ. APETx2 reduces the maximal conductance and induces a depolarizing shift in the voltage dependence of activation of Nav1.8. In current-clamp experiments, APETx2 reduces the number of action potentials (APs) evoked by a current ramp. Nav1.8 mediates most of the current during the AP upstroke and has been shown to be an important mediator of inflammatory pain. The fact that APETx2 inhibits two ion channels involved in inflammatory pain suggests that APETx2 or derivatives may represent novel analgesic compounds.RésuméL'acidose tissulaire est observée durant l'inflammation et entraine la douleur chez l'humain. Des canaux ioniques activés par les protons (H+) sont fortement exprimés dans les neurones sensoriels du système nerveux périphérique. De ceux-ci, les Acid-Sensing Ion Channels [ASICs) et Transient Receptor Potential Vanilloid-1 (TRPV1) présentent une sensibilité adéquate à l'acidité pour servir de détecteurs d'acidose.Les ASICs sont membres de la famille Degenerin/Epithelial Na* Channel. Six sous-unités ASIC ont été identifiées chez les mammifères (ASICla, -lb, -2a, -2b, -3 et -4). Les ASICs forment des canaux sélectifs au Na\ insensibles au voltage et activés par les H+. Les canaux fonctionnels sont des homo- ou hétérotrimères de sous-unités ASIC. TRPV1 est un membre de la famille TRP de canaux ioniques. Les canaux TRPV1 sont activés par les H+, la chaleur (T>43°Ç), les lipides, la capsaicine, le voltage et d'autres stimulus. L'activation de TRPV1 entraine un courant soutenu non-sélectif. Un stimulus peut augmenter la réponse de TRPV1 à un autre stimulus. Les H+ peuvent, par exemple, induire un décalage vers des valeurs plus faibles de la courbe de dépendance à la concentration de TRPV1 pour la capsaicine. Il a été démontré que les ASICs et TRPV1 sont impliqués dans la douleur inflammatoire. En utilisant la technique du patch-clamp, nous avons étudié différents aspects de la fonction des ASICs et de TRPV1 dans des contextes associés à la douleur.Dans la première partie de cette thèse, nous caractérisons l'effet d'une augmentation de température de 25 à 35°C sur la fonction des canaux ASICs et TRPV1, dans des cellules CHO transfectées et dans des cultures primaires de neurones sensoriels (DRG) de rat. L'activation des ASICs entraine l'apparition d'un courant transitoire tandis que l'activation de TRPV1 entraine un courant soutenu. De plus, les ASICs et TRPV1 possèdent des dépendances au pH différentes. Nous évaluons la contribution relative des ASICs et de TRPV1 au signalement électrique induit par les H+ et nous concluons que les ASICs sont les senseurs d'acidité les plus importants dans les neurones sensoriels, dans le domaine de pH de 7.4 à 6.0, à température corporelle.Les ASICs et TRPV1 sont exprimés dans l'épithélium recouvrant l'intérieur de la vessie (l'urothélium). Le Bladder Pain Syndrome/Interstitial Cystitis (BPS/IC) est une condition médicale douloureuse associée à une dysfonction de la barrière urothéliale et à une inflammation. Dans la seconde partie de cette thèse, nous démontrons que des cellules urothéliales (de la lignée cellulaire TEU2) et des cellules provenant de cultures primaires d'épithéliums de vessies humaines expriment des canaux ASIC fonctionnels mais pas de TRPV1 fonctionnels. De plus, nous montrons que le niveau d'expression de ASIC2 et -3 est augmenté dans l'urothélium de la vessie de patients souffrant de BPS/IC. Ces données suggèrent que les ASICs sont impliqués dans la pathologie BPS/IC.Pour finir, nous démontrons que la toxine APETx2 inhibe le canal spécifique aux neurones sensoriels Nav1.8, un membre de la famille des canaux sodiques dépendants du potentiel. Il a été démontré précédemment que la toxine APETx2 inhibe les canaux contenant une ou plusieurs sous-unités ASIC3 avec un ICso entre 0.08 et 1 μΜ. Nous montrons que la toxine APETx2 inhibe Nav1.8 avec un IC50 de «2.6 μΜ. La toxine APETx2 réduit la conductance maximale et induit un décalage de la dépendance au potentiel de Nav1.8 vers des valeurs plus positives. Dans des expériences de courant imposé sur des neurones sensoriels, la toxine APETx2 réduit le nombre de potentiels d'action induits par une rampe de courant. Nav1.8 est responsable de la majeure partie du courant durant la phase ascendante du potentiel d'action et a été démontré comme étant un médiateur important de la douleur inflammatoire. L'inhibition de deux types de canaux, impliqués dans la douleurs inflammatoire, par la toxine APETx2, suggère que cette dernière ou ses dérivés représentent des composés analgésiques prometteurs.

Cardiac dysfunction and impaired compensatory response to pressure overload in mice deficient in stem cell antigen-1.

Stem cell antigen-1 (Sca-1) has been used to identify cardiac stem cells in the mouse heart. To investigate the function of Sca-1 in aging and during the cardiac adaptation to stress, we used Sca-1-deficient mice. These mice developed dilated cardiomyopathy [end-diastolic left ventricular diameter at 18 wk of age: wild-type (WT) mice, 4.2 mm ± 0.3; Sca-1-knockout (Sca-1-KO) mice, 4.6 mm ± 0.1; ejection fraction: WT mice, 51.1 ± 2.7%; Sca-1-KO mice, 42.9 ± 2.7%]. Furthermore, the hearts of mice lacking Sca-1 demonstrated exacerbated susceptibility to pressure overload [ejection fraction after transaortic constriction (TAC): WT mice, 43.5 ± 3.2%; Sca-1-KO mice, 30.8% ± 4.0] and increased apoptosis, as shown by the 2.5-fold increase in TUNEL(+) cells in Sca-1-deficient hearts under stress. Sca-1 deficiency affected primarily the nonmyocyte cell fraction. Indeed, the number of Nkx2.5(+) nonmyocyte cells, which represent a population of cardiac precursor cells (CPCs), was 2-fold smaller in Sca-1 deficient neonatal hearts. In vitro, the ability of CPCs to differentiate into cardiomyocytes was not affected by Sca-1 deletion. In contrast, these cells demonstrated unrestricted differentiation into cardiomyocytes. Interestingly, proliferation of cardiac nonmyocyte cells in response to stress, as judged by BrdU incorporation, was higher in mice lacking Sca-1 (percentages of BrdU(+) cells in the heart after TAC: WT mice, 4.4 ± 2.1%; Sca-1-KO mice, 19.3 ± 4.2%). These data demonstrate the crucial role of Sca-1 in the maintenance of cardiac integrity and suggest that Sca-1 restrains spontaneous differentiation in the precursor population. The absence of Sca-1 results in uncontrolled precursor recruitment, exhaustion of the precursor pool, and cardiac dysfunction.

Hepatitis C virus proteins promote mitochondrial bioenergetic dysfunction and nitro-oxidative stress: insights into pathogenesis

HCV-infection induces a state of oxidative stress more pronounced than in many other inflammatory diseases. Here we propose a temporal sequence of events in the HCV-infected cell whereby the primary alteration consists in release of Ca2+ from the ER followed by uptake into mitochondria. This triggers successive mitochondrial dysfunctions leading to generation of ROS and to a progressive metabolic adaptive response. Pathogenetic implications of the model and new opportunities for therapeutic intervention are discussed.

Mécanismes physiopathologiques impliqués dans la dysfonction d'organes au cours du sepsis [Pathophysiological mechanisms of organ dysfunction in sepsis].

Sepsis is defined as the systemic inflammatory response to an infection. The occurrence of organ dysfunction increases the severity of sepsis. Complex interactions between multiple immunomodulating mediators and various cell populations, activated secondarily to the initial infectious insult, promote the development of organ dysfunction in sepsis. Although septic organ dysfunction has long been considered as the end result of chaotic, uncontrolled and deregulated inflammatory cascades, it might instead represent an adaptive response to avoid the occurrence of irreversible tissue damage and end-organ injury. In this article, we review the major mechanisms involved in organ dysfunction during sepsis, and also present the concept of organ dysfunction as an adaptive response to the septic process.

Dysfonction métabolique et stress chronique: un nouveau regard sur la pandémie de "diabésité" [Metabolic dysfunction and chronic stress: a new sight at "diabesity" pandemic]

Chronic stress in Western society can activate the autonomus, neuroendocrine and inflammatory/immunlogic systems. Chronic exposure to stressors can indeed stimulate the hypothalamic-pituitary-adrenal axis and induce a disbalance between anabolic and catabolic hormones, responsible of an increased in visceral fat and of insulin resistance. These metabolic consequences can lead to pre-diabetes. Exposure to chronic stress results in allostatic load and its pathophysiologic consequences. The knowledge of this mecanisms and the cardiovascular and metabolic risk related, should influence our way of thinking about patient care. To decrease allostatic load, practitioners can rely on therapeutic relation. Therapeutic education is one of the skill that can be use to create therapeutic relation.

Bacterial flagellin triggers cardiac innate immune responses and acute contractile dysfunction.

BACKGROUND: Myocardial contractile failure in septic shock may develop following direct interactions, within the heart itself, between molecular motifs released by pathogens and their specific receptors, notably those belonging to the toll-like receptor (TLR) family. Here, we determined the ability of bacterial flagellin, the ligand of mammalian TLR5, to trigger myocardial inflammation and contractile dysfunction. METHODOLOGY/PRINCIPAL FINDINGS: TLR5 expression was determined in H9c2 cardiac myoblasts, in primary rat cardiomyocytes, and in whole heart extracts from rodents and humans. The ability of flagellin to activate pro-inflammatory signaling pathways (NF-kappaB and MAP kinases) and the expression of inflammatory cytokines was investigated in H9c2 cells, and, in part, in primary cardiomyocytes, as well as in the mouse myocardium in vivo. The influence of flagellin on left ventricular function was evaluated in mice by a conductance pressure-volume catheter. Cardiomyocytes and intact myocardium disclosed significant TLR5 expression. In vitro, flagellin activated NF-kappaB, MAP kinases, and the transcription of inflammatory genes. In vivo, flagellin induced cardiac activation of NF-kappaB, expression of inflammatory cytokines (TNF alpha, IL-1 beta, IL-6, MIP-2 and MCP-1), and provoked a state of reversible myocardial dysfunction, characterized by cardiac dilation, reduced ejection fraction, and decreased end-systolic elastance. CONCLUSION/SIGNIFICANCE: These results are the first to indicate that flagellin has the ability to trigger cardiac innate immune responses and to acutely depress myocardial contractility.

Serum anticholinergic activity and postoperative cognitive dysfunction in elderly patients.

BACKGROUND: Cerebral cholinergic transmission plays a key role in cognitive function, and anticholinergic drugs administered during the perioperative phase are a hypothetical cause of postoperative cognitive dysfunction (POCD). We hypothesized that a perioperative increase in serum anticholinergic activity (SAA) is associated with POCD in elderly patients. METHODS: Seventy-nine patients aged >65 years undergoing elective major surgery under standardized general anesthesia (thiopental, sevoflurane, fentanyl, and atracurium) were investigated. Cognitive functions were assessed preoperatively and 7 days postoperatively using the extended version of the CERAD-Neuropsychological Assessment Battery. POCD was defined as a postoperative decline >1 z-score in at least 2 test variables. SAA was measured preoperatively and 7 days postoperatively at the time of cognitive testing. Hodges-Lehmann median differences and their 95% confidence intervals were calculated for between-group comparisons. RESULTS: Of the patients who completed the study, 46% developed POCD. Patients with POCD were slightly older and less educated than patients without POCD. There were no relevant differences between patients with and without POCD regarding gender, demographically corrected baseline cognitive functions, and duration of anesthesia. There were no large differences between patients with and without POCD regarding SAA preoperatively (pmol/mL, median [interquartile range]/median difference [95% CI], P; 1.14 [0.72, 2.37] vs 1.13 [0.68, 1.68]/0.12 [-0.31, 0.57], P = 0.56), SAA 7 days postoperatively (1.32 [0.68, 2.59] vs 0.97 [0.65, 1.83]/0.25 [-0.26, 0.81], P = 0.37), or changes in SAA (0.08 [-0.50, 0.70] vs -0.02 [-0.53, 0.41]/0.1 [-0.31, 0.52], P = 0.62). There was no significant relationship between changes in SAA and changes in cognitive function (Spearman rank correlation coefficient preoperatively of 0.03 [95% CI, -0.21, 0.26] and postoperatively of -0.002 [95% CI, -0.24, 0.23]). CONCLUSIONS: In this panel of patients with low baseline SAA and clinically insignificant perioperative anticholinergic burden, although a relationship cannot be excluded in some patients, our analysis suggests that POCD is probably not a substantial consequence of anticholinergic medications administered perioperatively but rather due to other mechanisms.

A New Species of Kritskyia (Dactylogyridae, Ancyrocephalinae) Parasite of Urinary Bladder of Prochilodus lineatus (Prochilodontidae, Characiformes) from the Floodplain of the High Paraná River, Brazil

A new species of Kritskyia inhabits the urinary bladder of the "curimba", Prochilodus lineatus in the floodplain of the high Paraná river. The new species resembles others members of Kritskyia in the following features: haptor lacking anchors and with 14 hooks marginal, posterior male copulatory organ non articulated with the accessory piece and vagina a sclerotized tube. However, it differs from the known species mainly by the shape of the copulatory complex. This is the third endoparasitic monogenean species reported from freshwater Neotropical fish.

Postoperative cognitive dysfunction POCD, serum anticholinergic activity and intraoperative cerebral perfusion in geriatric patients

Background: Inadequate intraoperative cerebral perfusion and increased serum anticholinergic activity (SAA) have been suggested as possible causes of postoperative cognitive dysfunction (POCD). Methods: 53 patients aged >65 yrs undergoing elective major surgical procedures under standardized general anaesthesia. Cerebral perfusion was monitored with transcranial Doppler and near-infrared spectroscopy. Mx, an index of cerebral autoregulation was calculated based on the correlation of spontaneous changes inmean arterial blood pressure (MAP) and cerebral blood flow velocity. Cognitive function was measured preoperatively and 7 days postoperatively using the CERAD-Neuropsychological Battery. A postoperative decline >1 z-score in at least 2 cognitive variables was defined as POCD. SAA was measured preoperatively and 7 days postoperatively (data available for 38 patients). CRP was measured at the same time points and 2 days postoperatively. Results: Age was 75_7 yrs (mean_SD). 23 patients (43%) developed POCD. There were no statistical significant differences between patients with POCD and without POCD in age (77_7 vs 73_6 yrs), MAP (74_12 vs 78_11 mmHg), cerebral tissue oxygenation indices (67_6 vs 69_4 %) SAA preoperatively (1.74_1.52 vs 1.74_1.21) and 7 days postoperatively (1.90_1.63 vs 1.84_1.39) and CRP preoperatively (32_72 vs 7_9), 2 days postoperatively (176_129 vs 111_69) and 7days postoperatively (53_43 vs 48_25). Patients with POCD had less efficient autoregulation than patients without POCD (Mx 0.55_0.15 vs 0.45_0.20, p = 0.046). However, the percentage of patients with clearly impaired autoregulation (ie, Mx>0.5) was statistically not different between groups (with POCD: 65%; without POCD: 38%; p = 0.06) but there seems to be a trend. Conclusions: Our data on the association between cerebral perfusion and POCD in elderly patients are inconclusive and more patients need to be investigated. In this small group of patients SAA seems not to be associated with POCD.

Troubles sexuels masculins et obésité [Male sexual dysfunction and obesity].

Obesity concerns more than 200 million people in the world, with an increasing prevalence in western countries. It is closely related to multiple medical conditions, such as diabetes and hypertension. It was recently shown that testosterone deficiency syndrome and erectile dysfunction (ED) are also linked to male obesity. In this group of patients, ED may be due to defects in corpus cavernosum relaxation, endocrine modifications and nerve signal alterations. Weight loss and increased physical activities can improve erectile function in 30% of obese patients. Additional medical treatments of ED enhance erectile function in more than 80% of patients. Self image improvement associated with appropriate erectile dysfunction medical treatment allow better sexual life and potentially increased motivation for weight loss.