Michel Bouvier

Effects of leptin on cat intestinal vagal mechanoreceptors

Vagal afferent nerve fibres are involved in the transmission to the central nervous system of information relating to food intake and immune reactions. Leptin is involved in the control of food intake and has specific receptors in afferent vagal neurones. To investigate the role of these receptors, we studied the effects of leptin on single vagal afferent activities from intestinal mechanoreceptors in anaesthetized cats. The activity of 35 intestinal vagal mechanoreceptors was recorded by means of glass microelectrodes implanted in the nodose ganglion. Leptin (10 μg), administered into the artery irrigating the upper part of the intestine, induced activation in 17 units (P < 0.001), inhibition in 8 units (P < 0.05), and had no effect on 10 units. The excitatory effects of leptin were blocked by the endogenous interleukine‐1β receptor antagonist, (Il‐1ra, 250 μg, i.a.). Cholecystokinin (CCK, 10 μg, i.a.) induced an activatory response only in the two types of units which were responsive to leptin alone. When leptin was administered after CCK, its excitatory effects were enhanced and its inhibitory effects were blocked, whereas it had no effect on the units which were not affected by leptin alone. The interactions between leptin and CCK are specific ones, since other substances (phenylbiguanide, a serotoninergic agonist; substance P) known to activate the mechanoreceptors did not modify the effects of leptin. These results indicate that leptin appears to play a role in the control of immune responses and food intake via intestinal vagal afferent nerve fibres and that there is a functional link between leptin and Il‐1β.

Effects of interactions between interleukin-1β and leptin on cat intestinal vagal mechanoreceptors

In a previous study, we established that leptin acts on chemosensitive intestinal vagal mechanoreceptors and that its excitatory effects are blocked by the endogenous interleukin‐1β receptor antagonist (Il‐1ra). To determine how interleukin‐1β (Il‐1β) is involved in the action of leptin, we studied the effects of this drug on the single vagal afferent activities of intestinal mechanoreceptors in anaesthetized cats. For this purpose, the activity of 34 intestinal vagal mechanoreceptors was recorded via glass microelectrodes implanted in the nodose ganglion. Il‐1β (1 μg) administered into the artery irrigating the upper part of the intestine activated both the 16 leptin‐activated units (type 1 units; P < 0.01) and the 12 leptin‐inhibited units (type 2 units; P < 0.001), but had no effect on the six leptin‐insensitive units. Cholecystokinin (CCK, 10 μg) induced an activatory response only in the two types of Il‐1β‐sensitive units. When Il‐1β was administered after CCK, its excitatory effects on type 1 units were enhanced, whereas the excitatory effects on type 2 units were abolished. Pre‐treatment with Il‐1ra (250 μg) blocked all the effects of Il‐1β and the excitatory effects of leptin on type 1 units, whereas it enhanced the inhibitory effects of leptin on type 2 units. It can therefore be concluded that (i) leptin acts on intestinal vagal mechanoreceptors via Il‐1β in the case of the type 1 units and independently of Il‐1β in the case of the type 2 units, and (ii) type 1 and type 2 units belong to two different populations of vagal afferents that transmit different information about ingestion or inflammation to the CNS, depending on the chemical environment.

Effects of leptin on cat intestinal motility

In a previous study, we established that leptin controls food intake and immune responses by acting on intestinal vagal chemosensitive mechanoreceptors via a functional link with interleukin‐1β (Il‐1β). Since the control of intestinal motility is one of the main roles of the vagal afferent fibres, we investigated the effects of leptin on intestinal electromyographic (EMG) activity which reflects intestinal motility. For this purpose, the effects of locally injected leptin on small intestine spontaneous EMG activity were studied in 23 anaesthetised cats. The EMG activity was recorded using bipolar electrodes implanted in the proximal small intestine. Leptin and Il‐1β (0.1, 1 and 10 μg), administered through the artery irrigating the upper part of the intestine 20 min after cholecystokinin (CCK, 10 μg, i.a.), had significant (P < 0.001) excitatory effects on intestinal EMG activity. The effects of both substances were blocked by the endogenous interleukin‐1β receptor antagonist (Il‐1ra, 250 μg, i.a.), by atropine (250 μg, i.a.) and by vagotomy. In the absence of CCK, leptin and Il‐1β had no effect on intestinal electrical activity. It can therefore be concluded that: (1) leptin is effective only after the previous intervention of CCK, (2) the enhancement of the electrical activity induced by leptin involves Il‐1β receptors and the cholinergic excitatory pathway, (3) the modes whereby the leptin‐induced enhancement of EMG activity occurs strongly suggest that these effects are due to a long‐loop reflex involving intestinal vagal afferent fibres and the parasympathetic nervous system.

Treatments of faecal incontinence: recommendations from the French National Society of Coloproctology

Faecal incontinence is common and significantly affects quality of life. Its treatment involves dietary manipulation, medical treatments, perineal rehabilitation or surgery. In this paper, the French National Society of Coloproctology offers recommendations based on the data in the current literature, including those on recently developed treatments. There is a lack of high quality data and most of the recommendations are therefore based either on grade of recommendation B or expert recommendation (Level 4). However, the literature supports the construction of an algorithm based on the available scientific evidence and expert recommendation which may be useful in clinical practice. The French National Society of Coloproctology proposes a decision‐making algorithm that includes recent developments of treatment. The current recommendations support sacral nerve modulation as the key treatment for faecal incontinence. They do not support the use of sphincter substitutions except in certain circumstances. Transanal irrigation is a novel often successful treatment of faecal incontinence due to neurological disorders.

Interferential therapy: a new treatment for slow transit constipation. A pilot study in adults

The study aimed to assess, for the first time, the effectiveness of interferential therapy (IFT) in the treatment of slow transit constipation in adults and its impact on the quality of life.

3D High-definition anorectal manometry: Values obtained in asymptomatic volunteers, fecal incontinence and chronic constipation. Results of a prospective multicenter study (NOMAD)

3D‐high definition anorectal manometry (3DARM) may aid the diagnosis of functional anorectal disorders, but data comparing asymptomatic and symptomatic subjects are scarce. We aimed to describe 3DARM values in asymptomatic volunteers and those with fecal incontinence (FI) or chronic constipation (CC), and identify which variables differentiate best these groups.

Three‐dimensional high‐resolution anorectal manometry: does it allow automated analysis of sphincter defects?

Anorectal manometry is the most common test used to explore anorectal disorders. The recent three‐dimensional high‐resolution anorectal manometry (3D‐HRAM) technique appears to be able to provide new topographic information. Our objective was to develop an automated analysis of 3D‐HRAM images to diagnose anal sphincter defects and compare the results with those of endoanal ultrasonography (EUS), which is considered to be the gold standard.

Rectal intussusception: can high resolution three-dimensional ano-rectal manometry compete with conventional defecography?

Three‐dimensional high‐resolution anorectal manometry (3DHRAM), used for exploring anorectal disorders, was recently developed, providing interesting topographic data for the diagnosis of pelvic floor disorders such as excessive perineal descent. The aim of our study was to define a diagnostic strategy based on selected 3DHRAM parameters to identify rectal intussusceptions (RI), considering conventional defecography (CD) as the gold standard.

High-resolution anorectal manometry may probably be worth every penny

We read with great attention “Highresolution anorectal manometry: an expensive hobby or worth every penny?” by Basilisco and Bharucha.1 This paper summarizes the advantages and limits of this recent technique that has focused interest for the past 10 years. Regarding our years of practice in this new technique, we would like to discuss specific important points that have not been addressed by the authors. Although usual parameters of anorectal manometry can be assessed with highresolution anorectal manometry (HRAM), other additional measures should be evaluated with this technique. Numerous studies have demonstrated that HRAM is an innovative tool to diagnose anal sphincter defects and pelvic floor disorders. Two studies have demonstrated that HRAM can diagnose anal sphincter defects with an interesting agreement with endoanal ultrasonography.2-4 Although the method to precisely measure anal sphincter defect should be established and validated, these data suggest a new interesting and useful aspect of HRAM. In our opinion, HRAM could assess in the same time both an anatomic and a functional defect by analyzing the anal sphincter function. The second important aspect of HRAM is its capacity to diagnose pelvic floor disorders. Studies have demonstrated that HRAM may not only diagnose perineal descent5,6 but also rectal intussusception7,8 and rectal prolapse9 taking conventional defecography or magnetic resonance defecography as a gold standard. This aspect of HRAM is probably building a new way to consider and interpret the new data that this innovative tool can offer. Of course, these new “anatomic” data have now to be precisely defined and new classifications of pelvic floor disorders observed with HRAM should be developed. Therefore, if HRAM can compete with endoanal ultrasonography and conventional or magnetic resonance defecography, it is clearly worth every penny.