Signaling switch of the urotensin II vasosactive peptide GPCR: prototypic chemotaxic mechanism in glioma.

Multiform glioblastomas (GBM) are the most frequent and aggressive primary brain tumors in adults. The poor prognosis is due to neo-angiogenesis and cellular invasion, processes that require complex chemotaxic mechanisms involving motility, migration and adhesion. Understanding these different cellular events implies identifying receptors and transduction pathways that lead to and promote either migration or adhesion. Here we establish that glioma express the vasoactive peptide urotensin II (UII) and its receptor UT and that UT-mediated signaling cascades are involved in glioma cell migration and adhesion. Components of the urotensinergic systems, UII and UT, are widely expressed in patient-derived GBM tissue sections, glioma cell lines and fresh biopsy explants. Interestingly, gradient concentrations of UII produced chemoattracting migratory/motility effects in glioma as well as HEK293 cells expressing human UT. These effects mainly involved the G13/Rho/rho kinase pathway while partially requiring Gi/o/PI3K components. In contrast, we observed that homogeneous concentrations of UII drastically blocked cell motility and stimulated cell-matrix adhesions through a UT/Gi/o signaling cascade, partially involving phosphatidylinositol-3 kinase. Finally, we provide evidence that, in glioma cells, homogeneous concentration of UII allowed translocation of Gα13 to the UT receptor at the plasma membrane and increased actin stress fibers, lamellipodia formation and vinculin-stained focal adhesions. UII also provoked a re-localization of UT precoupled to Gαi in filipodia and initiated integrin-stained focal points. Altogether, these findings suggest that UT behaves as a chemotaxic receptor, relaying a signaling switch between directional migration and cell adhesion under gradient or homogeneous concentrations, thereby redefining sequential mechanisms affecting tumor cells during glioma invasion. Taken together, our results allow us to propose a model in order to improve the design of compounds that demonstrate signaling bias for therapies that target specifically the Gi/o signaling pathway.

The endozepine ODN stimulates polyphosphoinositide metabolism in rat astrocytes.

Astrocytes synthesize a series of peptides called endozepines which act as endogenous ligands of benzodiazepine receptors. The present study demonstrates that the endozepine ODN causes a dose-dependent increase in inositol trisphosphate and a parallel decrease in phosphatidylinositol bisphosphate in cultured rat astrocytes. Pre-incubation of astrocytes with the phospholipase C inhibitor U 73122 or with pertussis toxin totally blocked polyphosphoinositide metabolism. These data show that, in rat astrocytes, ODN stimulates a phospholipase C coupled to a pertussis toxin-sensitive G protein.

The endozepine ODN stimulates [3H]thymidine incorporation in cultured rat astrocytes.

High concentrations of diazepam-binding inhibitor (DBI) mRNA have been detected in astrocytoma, suggesting that DBI-derived peptides may play a role in glial cell proliferation. In the present study, we have investigated the effect of a processing product of DBI, the octadecaneuropeptide ODN, on DNA synthesis in cultured rat astrocytes. At very low concentrations (10(-14) to 10(-11) M), ODN caused a dose-dependent increase of [3H]thymidine incorporation. At higher doses (10(-10) to 10(-5) M), the effect of ODN gradually declined. The central-type benzodiazepine receptor antagonist flumazenil (10(-6) M) completely suppressed the stimulatory action of ODN whereas the peripheral-type benzodiazepine receptor ligand, PK11195 (10(-6) M) had no effect. The ODN-induced stimulation of [3H]thymidine incorporation was mimicked by methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM). The GABAA receptor antagonist bicuculline (10(-4) M) suppressed the effect of both ODN and DMCM on DNA synthesis. Exposure of cultured astrocytes to the specific GABAA agonist 3APS (10(-10) to 10(-4) M) also induced a dose-related increase of [3H]thymidine incorporation. The present study indicates that ODN, acting through central-type benzodiazepine receptors associated with the GABAA receptor complex, stimulates DNA synthesis in rat glial cells. These data provide evidence for an autocrine role of endozepines in the control of glial cell proliferation.

Structure-activity relationships of a series of analogues of the octadecaneuropeptide ODN on calcium mobilization in rat astrocytes.

The octadecaneuropeptide ODN (QATVGDVNTDRPGLLDLK), originally characterized as an endogenous ligand for central-type benzodiazepine receptors, increases intracellular calcium concentration ([Ca2+]i) in rat astroglial cells. A series of ODN analogues was synthesized, and each compound was studied for its ability to induce Ca2+ mobilization in cultured rat astrocytes. Replacement of each amino acid by an L-alanine residue (AlaScan) showed that the N-terminal region of the molecule was relatively tolerant to alanine substitution (2-8, 10), except for the Ala9-substituted analogue (9) which was totally devoid of activity. Pyroglutamization (21) and acetylation (22) of the Gln1 residue reduced the Ca2+ response suggesting that a free N-terminal amine function is required for full activity of ODN. Alanine substitution of the residues in the C-terminal region of the molecule (11-14, 16-18) significantly reduced the biological activity of ODN. In particular, modifications of the Leu15 residue (15, 20) abolished the Ca2+-mobilizing activity. The analogues [Ala9]ODN (9), [Ala15]ODN (15), [D-Thr9]ODN (19), and [D-Leu15]ODN (20) partially antagonized the Ca2+ response evoked by ODN. Most importantly, the octapeptide ODN11-18 (OP, 24) produced a dose-response curve that was superimposable to that obtained with ODN, indicating that the C-terminal region of the molecule possesses full biological activity. Finally, the AlaScan of OP revealed that replacement of the Leu5 residue by Ala (29) or D-Leu (33) totally suppressed the calcium response, confirming the crucial contribution of the Leu15 residue of ODN to the biological activity of the neuropeptide.

Regulation of the expression of peripheral benzodiazepine receptors and their endogenous ligands during rat sciatic nerve degeneration and regeneration: a role for PBR in neurosteroidogenesis.

Peripheral benzodiazepine receptors (PBR) and their endogenous ligands, the diazepam-binding inhibitor derived-peptides, are present in Schwann cells in the peripheral nervous system. The aim of this study was to determine the influence of reversible (freeze-injury) and permanent (transection and ligature) nerve lesion on PBR density and on the levels of their endogenous ligands, by autoradiography (using [3H]PK11195) and radioimmunoassay (using antisera directed against the octadecaneuropeptide (ODN), a diazepam-binding inhibitor fragment). The potential role of PBR on peripheral nerve steroidogenesis, was studied by investigating the effect of specific PBR agonists and antagonists on pregnenolone levels in the sciatic nerve. Sixteen to 30 days after nerve lesion, PBR density and ODN-LI level were highly increased. Their expression returned to normal level when regeneration was completed 60 days after freeze-injury, but remained elevated when regeneration did not occur in transected distal stumps. Reverse-phase HPLC analysis of ODN-LI showed that in control nerve extracts, the major immunoreactive peak co-elutes with triakontatetraneuropeptide (TTN). After freeze-injury, intermediate molecular forms eluting between ODN and TTN were predominant and remained elevated at day 60. The greater accumulation of intermediate forms when regeneration is allowed to occur may indicate a particular role of these forms in axonal elongation and myelination. Ro5-4864, a high affinity PBR agonist increased pregnenolone concentration in the sciatic nerve. This effect was antagonised by PK11195, a high affinity PBR antagonist, which had no effect on pregnenolone basal level, indicating a specific action of PBR in neurosteroid production. These results suggest a role for PBR and their endogenous ligands in peripheral nerve regeneration. A trophic effect could be exerted via stimulation of steroid synthesis.

The stimulatory effect of the octadecaneuropeptide (ODN) on cytosolic Ca2+ in rat astrocytes is not mediated through classical benzodiazepine receptors.

Diazepam-binding inhibitor has been initially isolated from the rat brain from its ability to compete with benzodiazepines for their receptors. We have recently shown that the octadecaneuropeptide (diazepam-binding inhibitor-(33-50) or ODN) induces an increase in cytosolic free Ca2+ concentration ([Ca2+]i) in astroglial cells. The purpose of the present study was to determine whether central-type benzodiazepine receptors or peripheral-type benzodiazepine receptors are involved in the response of cultured rat astrocytes to ODN. The mixed central-/peripheral-type benzodiazepine receptor ligand flunitrazepam (10(-10) to 10(-6) M), the specific peripheral-type benzodiazepine receptor agonist Ro5-4864 (10(-10) to 10(-6) M) and the peripheral-type benzodiazepine receptor 'antagonist' PK 11195 (10(-9) to 10(-6) M) all induced a dose-dependent increase in [Ca2+]i. At high doses (10(-7) to 10(-5) M), the central-type benzodiazepine receptor agonist clonazepam also mimicked the stimulatory effect of ODN on [Ca2+]i. However, the [Ca2+]i rise induced by ODN was blocked neither by PK 11195 nor by the central-type benzodiazepine receptor antagonist flumazenil (10(-6) M each). Binding of [3H]flunitrazepam to intact astrocytes was displaced by low concentrations of the peripheral-type benzodiazepine receptor ligands flunitrazepam, Ro5 4864 and PK 11195, and by high concentrations of clonazepam. In contrast, ODN did not compete for [3H]flunitrazepam binding in intact cells. These data indicate that the effect of ODN on Ca2+ mobilization in rat astrocytes is mediated by high affinity receptors which are not related to classical benzodiazepine receptors.

Intravenous nutritional support in pregnancy. Experience following biliopancreatic diversion.

11 pregnant women with protein malnutrition following biliopancreatic diversion for obesity were supported by parenteral nutrition (PN). In 2 cases high concentration glucose, lipid emulsions and standard aminoacid mixtures were infused via a central venous catheter; in the other subjects, because oral intake was normal or increased, only aminoacids with or without lipids were administered through a peripheral vein. PN promoted foetal growth and was very well tolerated and totally safe both for mother and infant.

Food- and weight-related attitudes in obese persons: a longitudinal study over two years following biliopancreatic diversion.

Food- and weight-related attitudes were assessed in obese subjects prior to biliopancreatic diversion (BPD) and at 1 and 2 years after BPD, when any preoccupation with dieting and body weight and shape should have been abandoned. A decrease in the number of subjects whose food attitudes suggested some loss of control over food consumption, such as snacking, nibbling, getting hungry and eating in response to non-alimentary stimuli or arousal conditions was observed, confirming the role of dieting in leading to loss of control over food intake. The stable weight loss correlated with changes in the body attitudes and in the overall psychological status. The changes observed in obese persons after BPD suggest that 1) the food-related attitudes are influenced by the preoccupation with food and with dieting; 2) the weight-related attitudes are accounted for more by dissatisfaction with a body shape that is very different from the socially accepted one than by an individual's psychological traits.

[A new approach to gastric restriction surgery in treatment of obesity. Preliminary data]. / Un nuovo approccio alla chirurgia di restrizione gastrica nella terapia dell'obesità. Dati preliminari.

Following gastric surgery for obesity, a satisfactory weight loss and, above all, long-term weight maintenance can only be achieved in patients who have succeeded in radically changing their preoperative eating habits. In this preliminary study gastric banding is associated with rehabilitative training which was carried out using similar methods to the programs used for eating disorders. One year after surgery the results were substantially the same as those reported in the literature, with an overall weight loss of approximately 50%. The lack of correlation between weight loss and the degree of gastric banding underlines, even after a short interval, the efficacy and importance of postoperative re-educational training. The utility of this integrated approach will only be more fully evaluated after a longer period.

[Eating behavior and energy expenditure]. / Comportamento alimentare e spese energetiche.

The relationships between the resting energy expenditure (REE), measured by indirect calorimetry, and eating behavior, assessed by the "Three Factor Eating Questionnaire" were evaluated. The study was carried out in a group of healthy never-obese subjects and in two groups of formerly obese people, who have maintained a normal weight for more than two years. The subjects of the first formerly obese group had brought their body weight to normal by dieting. The second one comprised subjects following biliopancreatic diversion for obesity (BPD) in the long term, who maintain a normal weight because of the intestinal malabsorption due to the operation regardless of food consumption. In comparison with the other subjects, significantly higher cognitive restraint score values were observed in the post-diet subjects. Furthermore, a negative significant correlation between cognitive restraint and REE was found in the non operated subjects, while such correlation was not present in the BPD subjects. Therefore, in normal people cognitive restraint has to be considered to be related to behavioral-cognitive factors rather than biologically driven by energy requirements.

[Preoperative eating behavior and weight loss after gastric banding for obesity]. / Comportamento alimentare preoperatorio e calo ponderale dopo "gastric banding" per l'obesità.

The relationships between the cognitive restraint and the tendency to disinhibition prior to gastric banding for obesity, as assessed by the Three Factor Eating Questionnaire, and the weight loss at one year following the operation were investigated. The amount of overall weight loss was correlated positively to the disinhibition and negatively to the cognitive restraint score. When the food consumption overtakes the proximal gastric pouch capacity, the patient feels a strong aversive stimulus, thus stopping eating. Therefore, more is the patient's tendency to lose the control on food intake more is the postoperative weight loss. On the contrary, the high restraint patient only seldom feels such an aversive stimulus, and only seldom stops eating, thus the weight loss is smaller. Except for the overeating due to the disinhibition, the aversive stimulus arising from the gastric restriction cannot influence by itself any other aspect of eating behavior.

Chemotherapy-induced long-term alteration of executive functions and hippocampal cell proliferation: role of glucose as adjuvant.

In patients, cancer and treatments provoke cognitive impairments referred to "chemofog". Here a validated neurobehavioral animal model, the unique way to explore causal direct links between chemotherapy used in clinical practices and brain disorders, allowed investigation of the direct long-term impact of colo-rectal cancer chemotherapy on cognition and cerebral plasticity. Young and aged mice received three injections every 7 days during 2 weeks of 5-fluorouracil either alone (5-FU, 37.5 mg/kg) or in combination with oxaliplatin (3 mg/kg) or with glucose (5%). The long-term effects (from day 24 to day 60) of chemotherapy were tested on emotional reactivity, learning and memory, behavioral flexibility and hippocampal cell plasticity. 5-FU (in saline)-treated aged and also young mice exhibited specific altered cognitive flexibility and behavioral hyper-reactivity to novelty, whereas the combination 5-FU (in saline)/oxaliplatin (in glucose) did not provoke any cognitive dysfunction. We thus observed that glucose counteracted 5-FU-induced altered executive functions and hippocampal cell proliferation in vivo, and protected neural stem cells in vitro from toxicity of 5-FU or oxaliplatin. In conclusion, these data suggest that the lasting chemotherapy-induced selective impairment of executive functions, whatever the age, and associated with a reduced number of hippocampal proliferating cells, can be counteracted by co-administration with glucose.

[Interaction between hypnotic agents and the hypothalamic-pituitary-adrenocorticotropic axis during surgery]. / Modulation de l'axe hypothalamo-hypophyso-surrénalien par l'utilisation des agents hypnotiques dans le contexte chirurgical.

During stress, the relationship between the central nervous system and the immune system is essential to maintain homeostasis. The main neuroendocrine system involved in this interaction is the hypothalamic-pituitary-adrenal axis (HPA), which via the synthesis of glucocorticoids will modulate the intensity of the inflammatory response. Anaesthetic agents could be interacting with the HPA axis during surgery. Although etomidate currently remains in the center of the discussions, it seems, at least experimentally, that most hypnotics have the capacity to modulate the synthesis of adrenal steroids. Nevertheless, with the large literature on this subject, etomidate seems to be the most deleterious hypnotic agent on the HPA axis function. Its use should be limited when HPA axis is already altered.

Binge eating in obesity.

OBJECTIVE: To investigate the influence of dieting and of body shape dissatisfaction on binge eating. DESIGN: Longitudinal study following billiopancreatic diversion (BPD), when the body shape has become normal or nearly normal, and any worries over weight, dieting and food have probably been abandoned completely. SUBJECTS: 65 severely obese patients, evaluated by clinical semistructured interview for occurrence of binge eating episodes prior to, and at one and at two years following BPD. RESULTS: Whereas preoperative binge eating had been reported by 65% of the obese individuals, at two years following BPD binge eating occurred only in 9.2% of them. CONCLUSIONS: Weight stabilisation following BPD is associated with a sharp improvement in control over food intake, and this suggests the central role of dieting and/or of body dissatisfaction in causing binge eating episodes.

Body image in early-onset obese patients.

In a group of early-onset-obesity obese patients eating behaviour, body image and psychological condition were assessed by the Eating Disorder Inventory, the Three Factor Eating Questionnaire, the Body Shape Questionnaire and the Body Attitude Questionnaire. These evaluations were carried out prior to and at long-term follow-up after biliopancreatic diversion when body weight had steadily fallen towards normal values. The aim was to establish the influence of actual body weight and shape over body image. A notable improvement in eating behaviour and overall psychological conditions was observed, while the parameters assessing body image remained substantially unchanged, indicating that early-onset-obesity postobese subjects, despite having obtained normal or nearly normal weight conditions, are still much more dissatisfied with their body weight and somatic morphology than never-obese subjects with very similar actual body weights.

Binge eating in obesity: a longitudinal study following biliopancreatic diversion.

OBJECTIVE: Evaluating the influence of dieting and of being overweight on binge-eating episodes and on psychological traits in severely obese patients. METHODS: Clinical interviews and self-report questionnaires prior to and 2 years following biliopancreatic diversion (BPD) when subjects adopt a completely free eating style and achieve in maintaining a normal or nearly normal body weight. RESULTS: At two years following the operation, the prevalence of binge-eating episodes sharply fell and the subjects' overall psychological conditions improved; only a few patients started binging. DISCUSSION: These results point out the importance of dieting and of overweight itself in determining eating behavior disturbances or psychopathology. The fact that only a very small number of patients continue or start binging following BDP suggests that a minority of obese bingers should be considered as true eating-disordered patients.

Binge eating in massively obese patients undergoing bariatric surgery.

Data on the prevalence of binge eating in a series of 92 massively obese patients undergoing bariatric surgery are presented. A semistructured clinical interview demonstrated that 63 individuals had problems with binge eating, 43 of these reporting episodes of binge eating more than twice a week and then meeting the diagnostic criteria for binge eating disorder. By comparison with their nonbinge eating counterparts, binge eaters demonstrated higher body weight, greater weight fluctuation due to reducing diets in their past lifetime, higher Three-Factor Eating Questionnaire Disinhibition and Hunger score, and an overall higher psychopathology as assessed by the Eating Disorder Inventory. The great prevalence of binge eating in these patients could be accounted for by the high body weight, by the characteristics of the patients, or by the context in which the eating behavior assessment was carried out.

Eating behavior following biliopancreatic diversion for obesity: study with a three-factor eating questionnaire.

The eating behavior of obese patients and of subjects who had normalized their body weight following biliopancreatic diversion (BPD) was assessed by a three-factor eating questionnaire (TFEQ), constructed to measure cognitive dietary restraint, the tendency to disinhibition, and susceptibility to hunger. In the obese patients higher values of both disinhibition and hunger score were found than in normoweight persons. In BPD subjects a negative association between the time elapsed from the operation and both the disinhibition and hunger score values was observed. In patients operated more than 2 years before, the eating behavior, as assessed by the TFEQ, was similar to that of normoweight persons. After BPD the operated subjects do not have to respect any dietary advice, the loss of weight and the maintenance of a normal body weight occurring in spite of an absolutely free food consumption. Similarity to the control values of disinhibition and hunger score following BPD suggests that in the long term, when the preoccupation with food and diet is abandoned, a normal eating pattern can be achieved.

Enteral nutrition following total laryngectomy.

Body composition was measured in patients who underwent total laryngectomy for carcinoma and who were enterally fed throughout the postoperative period with full liquid artificial mixtures. The intestinal complications were very mild and required no changes in the nutritional program. Body sector sizes remained essentially unchanged until the end of the support, malnutrition did not occur and the postoperative local infection rate was very low. On the contrary, in patients fed with blenderized food, the amount of enteral infusion had to be reduced because of poor tolerance or abdominal discomfort; in this case caloric intake was largely inadequate. Fall in BW and BCM size and increase of TBNa/TBK ratio demonstrated a postoperative impairment of the nutritional status. Furthermore, the postoperative infection rate, the number of days with fever and the length of antibioticotherapy were higher than those observed in patients fed with full liquid mixtures.