Parasympathetic, but not sympathetic denervation, suppressed colorectal cancer progression.

Disruption in the nerve-tumor interaction is now considered as a possible anticancer strategy for treating various cancer types, particularly colorectal cancer. However, the underlying mechanisms are not still fully understood. Therefore, the present study aimed to evaluate the effects of sympathetic and parasympathetic denervation on the inhibition of colorectal cancer progression in early and late phases and assess the involvement of nerve growth factor in denervation mediated anticancer effects. One-hundred and fifty male Wistar rats were assigned into 15 groups. Seven groups comprising the control group, 1,2-dimethylhydrazine (DMH) group, sympathetic denervation group (celiac-mesenteric ganglionectomy and guanethidine sulphate administration), parasympathetic denervation group (vagotomy and atropine administration), and combination group were used in the early-stage protocol. For the late-stage protocol, eight groups comprising the control, DMH, surgical and pharmacological sympathetic and parasympathetic denervation groups, combination group, and 5-flourouracil group were considered. After 8 weeks, sympathetic and parasympathetic denervation significantly reduced ACF numbers in rats receiving DMH. On the other hand, in the late stages, parasympathetic but not sympathetic denervation resulted in significant reductions in tumor incidence, tumor volume and weight, cell proliferation (indicated by reduced immunostaining of PCNA and ki-67), and angiogenesis (indicated by reduced immunostaining of CD31 and VEGF expression levels), and downregulated NGF, ß2 adrenergic, and M3 receptors. It can be concluded that parasympathetic denervation may be of high importance in colon carcinogenesis and suggested as a possible therapeutic modality in late stages of colorectal cancer.

Mapping of Extrinsic Innervation of the Gastrointestinal Tract in the Mouse Embryo.

Precise extrinsic afferent (visceral sensory) and efferent (sympathetic and parasympathetic) innervation of the gut is fundamental for gut-brain cross talk. Owing to the limitation of intrinsic markers to distinctively visualize the three classes of extrinsic axons, which intimately associate within the gut mesentery, detailed information on the development of extrinsic gut-innervating axons remains relatively sparse. Here, we mapped extrinsic innervation of the gut and explored the relationships among various types of extrinsic axons during embryonic development in mice. Visualization with characterized intrinsic markers revealed that visceral sensory, sympathetic, and parasympathetic axons arise from different anatomic locations, project in close association via the gut mesentery, and form distinctive innervation patterns within the gut from embryonic day (E)10.5 to E16.5. Genetic ablation of visceral sensory trajectories results in the erratic extension of both sympathetic and parasympathetic axons, implicating that afferent axons provide an axonal scaffold to route efferent axons. Coculture assay further confirmed the attractive effect of sensory axons on sympathetic axons. Taken together, our study provides key information regarding the development of extrinsic gut-innervating axons occurring through heterotypic axonal interactions and provides an anatomic basis to uncover neural circuit assembly in the gut-brain axis (GBA).SIGNIFICANCE STATEMENT Understanding the development of extrinsic innervation of the gut is essential to unravel the bidirectional neural communication between the brain and the gut. Here, with characterized intrinsic markers targeting vagal sensory, spinal sensory, sympathetic, and parasympathetic axons, respectively, we comprehensively traced the spatiotemporal development of extrinsic axons to the gut during embryonic development in mice. Moreover, in line with the somatic nervous system, pretarget sorting via heterotypic axonal interactions is revealed to play critical roles in patterning extrinsic efferent trajectories to the gut. These findings provide basic anatomic information to explore the mechanisms underlying the process of assembling neural circuitry in the gut-brain axis (GBA).

Pressure overload changes mesenteric afferent nerve responses in a stress-dependent way in a fasting rat model.

It is well known that overload changes the mechanical properties of biological tissues and fasting changes the responsiveness of intestinal afferents. This study aimed to characterize the effect of overload on mechanosensitivity in mesenteric afferent nerves in normal and fasted Sprague-Dawley rats. Food was restricted for 7 days in the Fasting group. Jejunal whole afferent nerve firing was recorded during three distensions, i.e., ramp distension to 80 cmH2O luminal pressure (D1), sustained distension to 120 cmH2O for 2 min (D2), and again to 80 cmH2O (D3). Multiunit afferent recordings were separated into low-threshold (LT) and wide-dynamic-range (WDR) single-unit activity for D1 and D3. Intestinal deformation (strain), distension load (stress), and firing frequency of mesenteric afferent nerve bundles [spike rate increase ratio (SRIR)] were compared at 20 cmH2O and 40 cmH2O and maximum pressure levels among distensions and groups. SRIR and stress changes showed the same pattern in all distensions. The SRIR and stress were larger in the Fasting group compared to the Control group (P < 0.01). SRIR was lower in D3 compared to D1 in controls (P < 0.05) and fasting rats (P < 0.01). Total single units and LT were significantly lower in Fasting group than in Controls at D3. LT was significantly higher in D3 than in D1 in Controls. Furthermore, correlation was found between SRIR with stress (R = 0.653, P < 0.001). In conclusion, overload decreased afferent mechanosensitivity in a stress-dependent way and was most pronounced in fasting rats. Fasting shifts LT to WDR and high pressure shifts WDR to LT in response to mechanical stimulation.

Precise anatomical resection based on structures of nerve and fibrous tissue around the superior mesenteric artery for mesopancreas dissection in pancreaticoduodenectomy for pancreatic cancer.

BACKGROUND: The aim of the present study was to investigate the feasibility of resection based on the nerve and fibrous tissue (NFT) structures around the superior mesenteric artery (SMA) for resectable pancreatic adenocarcinoma (R-PDAC) patients. METHODS: NFTs around the SMA were classified into four "intensive NTFs area" with spreading the NFTs around the SMA and three SMA nerve plexus regions without branching nerves according to autopsy findings. Complete dissection of four "intensive NTFs areas" was performed by pre-exposing three SMA nerve plexus regions without branching nerves as "dissection-guiding points" with SMA nerve plexus preservation (NFT-based resection). Among 157 R-PDAC patients undergoing pancreaticoduodenectomy, surgical outcomes of 78 patients with NFT-based resection were compared with 59 patients with half-SMA nerve plexus dissection and 20 patients without NFTs dissection. RESULTS: In the NFT-based resection group, 76.5% had tumor involvement and metastasis in each intensive NTFs area. Operative time, blood loss, and postoperative diarrhea rate were significantly lower in NFT-based resection than in half-SMA nerve plexus group (321 vs 390 min; P < .01, 228 vs 550 mL; P < .01, 5.1% vs 15.3%; P = .04, respectively). R0 rate and median overall survival significantly improved in NFT-based resection than in non-NFT dissection group (93.6% vs 65.0%; P < .01, 49.6 vs 23.6 months, P = .01). CONCLUSION: NFT-based resection may become a novel method for R-PDAC patients.

Electrical stimulation of the vagus nerve improves intestinal blood flow after trauma and hemorrhagic shock.

BACKGROUND: Gut damage after trauma/hemorrhagic shock contributes to multiple organ dysfunction syndrome. Electrical vagal nerve stimulation is known to prevent gut damage in animal models of trauma/hemorrhagic shock by altering the gut inflammatory response; however, the effect of vagal nerve stimulation on intestinal blood flow, which is an essential function of the vagus nerve, is unknown. This study aimed to determine whether vagal nerve stimulation influences the abdominal vagus nerve activity, intestinal blood flow, gut injury, and the levels of autonomic neuropeptides. METHODS: Male Sprague Dawley rats were anesthetized, and the cervical and abdominal vagus nerves were exposed. One pair of bipolar electrodes was attached to the cervical vagus nerve to stimulate it; another pair of bipolar electrodes were attached to the abdominal vagus nerve to measure action potentials. The rats underwent trauma/hemorrhagic shock (with maintenance of mean arterial pressure of 25 mmHg for 30 min) without fluid resuscitation and received cervical vagal nerve stimulation post-injury. A separate cohort of animals were subjected to transection of the abdominal vagus nerve (vagotomy) just before the start of cervical vagal nerve stimulation. Intestinal blood flow was measured by laser Doppler flowmetry. Gut injury and noradrenaline level in the portal venous plasma were also assessed. RESULTS: Vagal nerve stimulation evoked action potentials in the abdominal vagus nerve and caused a 2-fold increase in intestinal blood flow compared to the shock phase (P < .05). Abdominal vagotomy eliminated the effect of vagal nerve stimulation on intestinal blood flow (P < .05). Vagal nerve stimulation protected against trauma/hemorrhagic shock -induced gut injury (P < .05), and circulating noradrenaline levels were decreased after vagal nerve stimulation (P < .05). CONCLUSION: Cervical vagal nerve stimulation evoked abdominal vagal nerve activity and relieved the trauma/hemorrhagic shock-induced impairment in intestinal blood flow by modulating the vasoconstriction effect of noradrenaline, which provides new insight into the protective effect of vagal nerve stimulation.

Clinical Outcomes in Early Cervical Cancer Patients Treated with Nerve Plane-sparing Laparoscopic Radical Hysterectomy.

STUDY OBJECTIVE: To explore the feasibility of nerve plane-sparing laparoscopic radical hysterectomy (NPS-LRH) as a simplified C1-type surgery for cervical cancer patients and to compare this technique with laparoscopic radical hysterectomy (LRH). DESIGN: A retrospective comparative study. SETTING: An academic tertiary hospital affiliated with the Chinese National Cancer Center. PATIENTS: Six hundred fifteen patients with Fédération Internationale de Gynécologie et d'Obstétrique stage Ib and IIa cervical cancer who underwent laparoscopic radical hysterectomy between January 2010 and December 2017 were enrolled. Among them, 263 patients underwent the NPS-LRH surgery, and 352 patients underwent the LRH surgery. Intraoperative data and postoperative outcomes were compared between the 2 groups. INTERVENTIONS: NPS-LRH is a simplified type C1 procedure that preserves the ureteral mesentery and its nerve plane, whereas LRH is a type C2 procedure in the Querleu-Morrow surgical classification system. MEASUREMENTS AND MAIN RESULTS: There were no statistically significant differences in age, body mass index, Fédération Internationale de Gynécologie et d'Obstétrique stage, tumor differentiation, pathological type, depth of invasion, lymphovascular space invasion, parametrial tissue invasion, lymphatic metastasis, neoadjuvant chemotherapy, or postoperative adjuvant radiotherapy and chemotherapy between the 2 groups. Compared with the LRH group, the NPS-LRH group had a shorter length of operation (238.7 ± 53.9 minutes vs 259.8 ± 56.6 minutes, p < .01), less intraoperative bleeding (p < .01), more resected lymph nodes (p = .028), shorter duration of urinary catheterization (p < .01), lower incidences of postoperative hydronephrosis (p = .044), less long-term frequent urination (p < .01), less acute urinary incontinence (p < .01), poor bladder sensation (p = .028), and constipation (p = .029). There were no statistically significant differences in the disease-free survival and overall survival between the 2 groups (p = .769 and .973, respectively). CONCLUSION: NPS-LRH is a simplified, safe, and feasible type C1 operation that had a shorter length of operation, less intraoperative bleeding, more resected lymph nodes, and better postoperative bladder function compared with the LRH group. Further studies are required to assess its benefits on rectal function and long-term prognosis.

[Mechanism and anatomy recognition of neurovascular bundle injury from different perspectives of transabdominal and transanal approach].

The neurovascular bundle (NVB) starts at the lateral angle of the seminal vesicle (the initial part), passes posterolateral of the prostate gland (the main part), and ends at the cavernous body of the penis (the cavernous part). In low rectal surgery, different transabdominal and transanal perspectives result in different NVB injury risks. In the perspective of transabdominal operation, the separation between the initial part of NVB and Denonvilliers fascia and the anatomical variation of the two lateral sides of Denonvilliers fascia increases the risk of NVB injury, and conformation separation may take into account the convenience of separationand the protection of NVB. In the perspective of transanal operation, when separating the main part with NVB and mesorectum, the perspective of the transanal, unidirection traction and excessive dissection increase the risk of NVB main exposure. Clear anatomical identification helps the protection of NVB in the transanal operation. At present, the medical evidence on the difference of NVB injury in different perspectives of transabdominal and transanal approach is still in need of relevant clinical researches.

The expression of androgen receptor in neurons of the anterior pelvic ganglion and celiac-superior mesenteric ganglion in the male pig.

The present study investigated the expression of androgen receptor (AR) in neurons of the anterior pelvic ganglion (APG) and celiac-superior mesenteric ganglion (CSMG; ganglion not involved in the innervation of reproductive organs) in the male pig with quantitative real-time PCR (qPCR) and immunohistochemistry. qPCR investigations revealed that the level of AR gene expression in the APG tissue was approximately 2.5 times higher in the adult (180-day-old) than in the juvenile (7-day-old) boars. Furthermore, in both the adult and juvenile animals it was sig- nificantly higher in the APG than in CSMG tissue (42 and 85 times higher, respectively). Immu- nofluorescence results fully confirmed those obtained with qPCR. In the adult boars, nearly all adrenergic (DßH-positive) and the majority of non-adrenergic neurons in APG stained for AR. In the juvenile animals, about half of the adrenergic and non-adrenergic neurons were AR-posi- tive. In both the adult and juvenile animals, only solitary CSMG neurons stained for AR. The present results suggest that in the male pig, pelvic neurons should be considered as an element of highly testosterone-dependent autonomic circuits involved in the regulation of urogenital func- tion, and that their sensitization to androgens is a dynamic process, increasing during the prepu- bertal period.

Bowel Motility After Injury to the Superior Mesenteric Plexus During D3 Extended Mesenterectomy.

BACKGROUND: Improvement of lymphadenectomy in right colectomy requires removal of all tissue surrounding the superior mesenteric vessels beneath the pancreatic notch. Short- and long-term bowel motility disorders after D3 extended mesenterectomy with consecutive superior mesenteric plexus transection are studied. METHODS: Patients without pre-existing motility disorders undergoing D3 extended mesenterectomy were examined 3 times using the wireless motility capsule: before, at 3 wk, and 6 mo after surgery. Segmental transit times and contractility were analyzed using mixed effect modeling. Correlation between contractility and transit time was assessed by the Pearson correlation coefficient. RESULTS: Fifteen patients (4 men), with median age 62 y, were included. Mean values for the three consecutive examinations are as follows. Gastric transit time increased from 237 to 402 and 403 min, respectively. Small bowel transit time decreased from 246 to 158 (P < 0.01) and 199 (P = 0.03) min, respectively. Colonic transit time decreased from 1742 to 1450 and 1110 (P = 0.02) min, respectively. Gastric contractions per minute (CPM) varied from 1.73 to 1.05 (P = 0.01) and 2.47 (P < 0.01), respectively. Small bowel CPM decreased from 3.43 to 2.68 and 3.34, respectively. Colonic CPM ranged from 1.59 to 1.45 and 1.91 (P = 0.08), respectively. Correlation between small bowel (SB) transit time and CPM was -0.45 (P = 0.09) preoperatively, and -0.03 (P = 0.91) 6 mo postoperatively. CONCLUSIONS: Extrinsic SB denervation leads to significantly accelerated SB transit, reduced contractility, and disturbed correlation between transit time and contractility early after denervation. Both number of contractions and transit time in the denervated SB show a clear tendency toward normalization at 6 mo.

Imanaga's First Method for Reconstruction with Preservation of Mesojejunal Autonomic Nerves During Pylorus-Preserving Pancreatoduodenectomy.

BACKGROUND Pancreatic surgeries have undergone substantial development. Pancreaticoduodenectomy and pylorus-preserving pancreatoduodenectomy inherently require reconstruction. In 1960, Professor Imanaga introduced a reconstructive technique performed in the order of the gastric remnant, pancreatic duct, and biliary tree from the viewpoint of physiologic function after pancreaticoduodenectomy. We herein report our experience with Imanaga's first method during pylorus-preserving pancreatoduodenectomy and retrospectively evaluate the short- and long-term outcomes. Technicalities and pitfalls are also discussed. CASE REPORT Eight patients were evaluated (mean follow-up period, 16.7 ± 1.0 years). Mesojejunal autonomic nerves were preserved without tension to the greatest extent possible for reconstruction. Intentional dissection of regional lymph nodes and nerves was performed in five and two patients, respectively. During the short-term postoperative period, one patient developed pancreatic leakage resulting in an intraperitoneal abscess, and endoscopic transgastric drainage was required. Two patients developed delayed gastric emptying. In three patients, passage from the duodenojejunostomy to pancreaticojejunostomy was mechanically disturbed, and endoscopic dilations with a balloon bougie were repeated. Repeated cholangitis was observed in three patients. During the long-term postoperative period, neither cachexia nor sarcopenia was observed, although two patients had diabetes. Two patients were free from all medications. Three patients who did not undergo intentional dissection of lymph nodes and nerves showed acceptable short- and long-term outcomes, although one each developed repeated cholangitis and adhesive ileus during the short-term period. CONCLUSIONS Imanaga's first reconstruction may have potential benefits, especially for diseases that do not require intentional dissection. Adequate mobilization of the pancreatic remnant is important for successful reconstruction.

The Role of the Mesentery in Crohn's Disease: The Contributions of Nerves, Vessels, Lymphatics, and Fat to the Pathogenesis and Disease Course.

Crohn's disease (CD) is a complex gastrointestinal disorder involving multiple levels of cross talk between the immunological, neural, vascular, and endocrine systems. The current dominant theory in CD is based on the unidirectional axis of dysbiosis-innate immunity-adaptive immunity-mesentery-body system. Emerging clinical evidence strongly suggests that the axis be bidirectional. The morphologic and/or functional abnormalities in the mesenteric structures likely contribute to the disease progression of CD, to a less extent the disease initiation. In addition to adipocytes, mesentery contains nerves, blood vessels, lymphatics, stromal cells, and fibroblasts. By the secretion of adipokines that have endocrine functions, the mesenteric fat tissue exerts its activity in immunomodulation mainly through response to afferent signals, neuropeptides, and functional cytokines. Mesenteric nerves are involved in the pathogenesis and prognosis of CD mainly through neuropeptides. In addition to angiogenesis observed in CD, lymphatic obstruction, remodeling, and impaired contraction maybe a cause and consequence of CD. Lymphangiogenesis and angiogenesis play a concomitant role in the progress of chronic intestinal inflammation. Finally, the interaction between neuropeptides, adipokines, and vascular and lymphatic endothelia leads to adipose tissue remodeling, which makes the mesentery an active participator, not a bystander, in the disease initiation and precipitation CD. The identification of the role of mesentery, including the structure and function of mesenteric nerves, vessels, lymphatics, and fat, in the intestinal inflammation in CD has important implications in understanding its pathogenesis and clinical management.

Alterations of neurochemical expression of the coeliac-superior mesenteric ganglion complex (CSMG) neurons supplying the prepyloric region of the porcine stomach following partial stomach resection.

The purpose of the present study was to determine the response of the porcine coeliac-superior mesenteric ganglion complex (CSMG) neurons projecting to the prepyloric area of the porcine stomach to peripheral neuronal damage following partial stomach resection. To identify the sympathetic neurons innervating the studied area of stomach, the neuronal retrograde tracer Fast Blue (FB) was applied to control and partial stomach resection (RES) groups. On the 22nd day after FB injection, following laparotomy, the partial resection of the previously FB-injected stomach prepyloric area was performed in animals of RES group. On the 28th day, all animals were re-anaesthetized and euthanized. The CSMG complex was then collected and processed for double-labeling immunofluorescence. In control animals, retrograde-labelled perikarya were immunoreactive to tyrosine hydroxylase (TH), dopamine ß-hydroxylase (DßH), neuropeptide Y (NPY) and galanin (GAL). Partial stomach resection decreased the numbers of FB-positive neurons immunopositive for TH and DßH. However, the strong increase of NPY and GAL expression, as well as de novo-synthesis of neuronal nitric oxide synthase (nNOS) and leu5-Enkephalin (LENK) was noted in studied neurons. Furthermore, FB-positive neurons in all pigs were surrounded by a network of cocaine- and amphetamine-regulated transcript peptide (CART)-, calcitonin gene-related peptide (CGRP)-, and substance P (SP)-, vasoactive intestinal peptide (VIP)-, LENK- and nNOS- immunoreactive nerve fibers. This may suggest neuroprotective contribution of these neurotransmitters in traumatic responses of sympathetic neurons to peripheral axonal damage.

Interdependency between mechanical parameters and afferent nerve discharge in hypertrophic intestine of rats.

Partial intestinal obstruction causes smooth muscle hypertrophy, enteric neuronal plasticity, motility disorders, and biomechanical remodeling. In this study we characterized the stimulus-response function of afferent fibers innervating the partially obstructed jejunum. A key question is whether changes in afferent firing arise from remodeled mechanical tissue properties or from adaptive afferent processes. Partial obstruction was created by placing a polyethylene ring for 2 wk in jejunum of seven rats. Sham obstruction was made in six rats and seven rats served as normal controls. Firing from mesenteric afferent nerve bundles was recorded during mechanical ramp, relaxation, and creep tests. Stress-strain, spike rate increase ratio (SRIR), and firing rate in single units were assessed for evaluation of interdependency of the mechanical stimulations, histomorphometry data, and afferent nerve discharge. Partial intestinal obstruction resulted in hypertrophy and jejunal stiffening proximal to the obstruction site. Low SRIR at low strains during fast distension and at high stresses during slow distension was found in the obstructed rats. Single unit analysis showed increased proportion of mechanosensitive units but absent high-threshold (HT) units during slow stimulation, decreased number of HT units during fast stimulation, and shift from HT sensitivity towards low threshold sensitivity in the obstructed jejunum. Biomechanical remodeling and altered afferent response to mechanical stimulations were found in the obstructed jejunum. Afferents from obstructed jejunum preserved their function in encoding ongoing mechanical stimulation but showed changes in their responsiveness. The findings support that mechanical factors rather than adaption are important for afferent remodeling.

Characterization of Perivascular Nerve Distribution in Rat Mesenteric Small Arteries.

The distribution pattern of perivascular nerves in some branches of rat mesenteric arteries was studied. Mesenteric arteries isolated from 8-week-old Wistar rats were divided into the 1st-, 2nd-, and 3rd-order branches. The distribution of perivascular nerves in each branch was immunohistochemically evaluated using antibodies against neuropeptide Y (NPY), tyrosine hydroxylase (TH), calcitonin gene-related peptide (CGRP), substance P (SP), and neuronal nitric oxide synthase (nNOS). The density of NPY-, TH-, CGRP-, and SP-like immunoreactive (LI) nerves in the 2nd and 3rd branches was significantly greater than that in the 1st branch, and a negative relationship was found between nerve density and arterial diameter, except for TH-LI nerves. The density of NPY- and TH-LI nerves in all branches, which was similar, was greater than that of CGRP- (except for NPY-LI nerves in the 1st branch), SP-, or nNOS-LI nerves. Double immunostaining revealed that TH-LI nerves made contact with nNOS-LI, CGRP-LI, and SP-LI nerves and that CGRP-LI nerves made contact with TH-, NPY-, or nNOS-LI nerves, while TH-LI and CGRP-LI nerves nearly merged with NPY-LI and SP-LI nerves, respectively. These results suggest that the each branch of mesenteric arteries is densely innervated by vasoconstrictor nerves containing NPY, TH, and vasodilator CGRP nerves. They also suggest that the intense density of perivascular nerves in the 2nd and 3rd branches may contribute to maintaining vascular tone.

Caudal mesenteric ganglion in the sheep - macroanatomical and immunohistochemical study.

The caudal mesenteric ganglion (CaMG) is a prevetrebral ganglion which provides innervation to a number of organs in the abdominal and pelvic cavity. The morphology of CaMG and the chemical coding of neurones in this ganglion have been described in humans and many animal species, but data on this topic in the sheep are entirely lacking. This prompted us to undertake a study to determine the localization and morphology of sheep CaMG as well as immunohistochemical properties of its neurons. The study was carried out on 8 adult sheep, weighing from 40 to 60 kg each. The sheep were deeply anaesthetised and transcardially perfused with 4% paraformaldehyde. CaMG-s were exposed and their location was determined. Macroanatomical observations have revealed that the ovine CaMG is located at the level of last two lumbar (L5 or L6) and the first sacral (S1) vertebrae. The ganglion represents an unpaired structure composed of several, sequentially arranged aggregates of neurons. Immunohistochemical investigations revealed that nearly all (99.5%) the neurons were DßH-IR and were richly supplied by VACHT-IR nerve terminals forming "basket-like" structures around the perikarya. VACHT-IR neurones were not determined. Many neurons (55%) contained immunoreactivity to NPY, some of them (10%) stained for Met-ENK and solitary nerve cells were GAL-positive. CGRP-IR nerve fibres were numerous and a large number of them simultaneously expressed immunoreactivity to SP. Single, weakly stained neurones were SP-IR and only very few nerve cells weakly stained for VIP.

The TRPV1 channel in rodents is a major target for antinociceptive effect of the probiotic Lactobacillus reuteri DSM 17938.

Certain probiotic bacteria have been shown to reduce distension-dependent gut pain, but the mechanisms involved remain obscure. Live luminal Lactobacillus reuteri (DSM 17938) and its conditioned medium dose dependently reduced jejunal spinal nerve firing evoked by distension or capsaicin, and 80% of this response was blocked by a specific TRPV1 channel antagonist or in TRPV1 knockout mice. The specificity of DSM action on TRPV1 was further confirmed by its inhibition of capsaicin-induced intracellular calcium increases in dorsal root ganglion neurons. Another lactobacillus with ability to reduce gut pain did not modify this response. Prior feeding of rats with DSM inhibited the bradycardia induced by painful gastric distension. These results offer a system for the screening of new and improved candidate bacteria that may be useful as novel therapeutic adjuncts in gut pain. Certain bacteria exert visceral antinociceptive activity, but the mechanisms involved are not determined. Lactobacillus reuteri DSM 17938 was examined since it may be antinociceptive in children. Since transient receptor potential vanilloid 1 (TRPV1) channel activity may mediate nociceptive signals, we hypothesized that TRPV1 current is inhibited by DSM. We tested this by examining the effect of DSM on the firing frequency of spinal nerve fibres in murine jejunal mesenteric nerve bundles following serosal application of capsaicin. We also measured the effects of DSM on capsaicin-evoked increase in intracellular Ca(2+) or ionic current in dorsal root ganglion (DRG) neurons. Furthermore, we tested the in vivo antinociceptive effects of oral DSM on gastric distension in rats. Live DSM reduced the response of capsaicin- and distension-evoked firing of spinal nerve action potentials (238 ± 27.5% vs. 129 ± 17%). DSM also reduced the capsaicin-evoked TRPV1 ionic current in DRG neuronal primary culture from 83 ± 11% to 41 ± 8% of the initial response to capsaicin only. Another lactobacillus (Lactobacillus rhamnosus JB-1) with known visceral anti-nociceptive activity did not have these effects. DSM also inhibited capsaicin-evoked Ca(2+) increase in DRG neurons; an increase in Ca(2+) fluorescence intensity ratio of 2.36 ± 0.31 evoked by capsaicin was reduced to 1.25 ± 0.04. DSM releasable products (conditioned medium) mimicked DSM inhibition of capsaicin-evoked excitability. The TRPV1 antagonist 6-iodonordihydrocapsaicin or the use of TRPV1 knock-out mice revealed that TRPV1 channels mediate about 80% of the inhibitory effect of DSM on mesenteric nerve response to high intensity gut distension. Finally, feeding with DSM inhibited perception in rats of painful gastric distension. Our results identify a specific target channel for a probiotic with potential therapeutic properties.

Modulation of voltage-gated Ca2+ channels by G protein-coupled receptors in celiac-mesenteric ganglion neurons of septic rats.

Septic shock, the most severe complication associated with sepsis, is manifested by tissue hypoperfusion due, in part, to cardiovascular and autonomic dysfunction. In many cases, the splanchnic circulation becomes vasoplegic. The celiac-superior mesenteric ganglion (CSMG) sympathetic neurons provide the main autonomic input to these vessels. We used the cecal ligation puncture (CLP) model, which closely mimics the hemodynamic and metabolic disturbances observed in septic patients, to examine the properties and modulation of Ca2+ channels by G protein-coupled receptors in acutely dissociated rat CSMG neurons. Voltage-clamp studies 48 hr post-sepsis revealed that the Ca2+ current density in CMSG neurons from septic rats was significantly lower than those isolated from sham control rats. This reduction coincided with a significant increase in membrane surface area and a negligible increase in Ca2+ current amplitude. Possible explanations for these findings include either cell swelling or neurite outgrowth enhancement of CSMG neurons from septic rats. Additionally, a significant rightward shift of the concentration-response relationship for the norepinephrine (NE)-mediated Ca2+ current inhibition was observed in CSMG neurons from septic rats. Testing for the presence of opioid receptor subtypes in CSMG neurons, showed that mu opioid receptors were present in ~70% of CSMG, while NOP opioid receptors were found in all CSMG neurons tested. The pharmacological profile for both opioid receptor subtypes was not significantly affected by sepsis. Further, the Ca2+ current modulation by propionate, an agonist for the free fatty acid receptors GPR41 and GPR43, was not altered by sepsis. Overall, our findings suggest that CSMG function is affected by sepsis via changes in cell size and α2-adrenergic receptor-mediated Ca2+ channel modulation.

Morphology and distribution of lamellar corpuscles in the mesentery of the cat.

Mesentery samples obtained from 13 mixed breed cats were stereoscopically and microscopically examined and yielded the following results. In the mesentery, lamellar corpuscles were densely distributed around blood vessels, with a mean number of 182.2 ± 20.9 and mean maximum and minimum diameters of 0.98 ± 0.18 mm and 0.54 ± 0.08 mm, respectively. While most lamellar corpuscles were isolated, some complex lamellar corpuscles were found in the mesentery. Lamellar corpuscles in the mesentery appear to serve more as internal receptors that detect changes in the internal environment than as external receptors. In addition, those found around blood vessels in the mesentery are likely to be involved in blood pressure regulation.

[Participation of peripheral sensory structures of autonomic nervous system in the mechanisms of neuroimmune interactions].

On the basis of the electrophysiological research carried out with immunohystochemical methods on rats, it is found, that introduction of products of mast cell degranulation into blood as well as endogenous release of mast cell mediators with either the compound 48/80 or introduction of egg albumin to presensitized rats, enhances activity of mesenteric afferent nerve fibers. The obtained data provide evidence that intestinal afferents contribute an early signal to the brain regarding potential pathogens. The question of whether or not the intrinsic enteric neurons are involved in these processes, however, has not been carefully studied. So we investigated this problem and found that the enteric neurons express receptor of innate immunity TLR4 and nociceptive vanilloid receptor TRPV1, by means ofimmunohistochemical method. The analysis of neurons distribution revealed that vanilloid receptors are expressed by neurons localized mainly in myenteric plexus whereas TLR4-immunoreactive neurons generally are present in submucous plexus. It is also established coexpression of both receptors in the single intrinsic enteric neuron. In conclusion, our findings indicate that sensory terminals of external afferent fibers as well as intrinsic neurons of intestine can modulate reactions of the organism to endotoxins and thus may be involved in reception of inflammatory and immune responses.