Parasympathetic Markers Research Articles

The clinicopathological and prognostic significance of autonomic nerves in salivary duct carcinoma.

Many researchers have focused on the role of the autonomic nervous system in the tumor microenvironment. Autonomic nerves include the sympathetic and parasympathetic nerves, which are known to induce cancer growth and metastasis. However, in salivary duct carcinoma (SDC), a rare and highly malignant tumor, the issue should be investigated from both biological and therapeutic perspectives. We explored the clinicopathological and prognostic implications of the autonomic nerves in 129 SDCs. Immunohistochemistry was performed to determine the nature of each nerve using antibodies against S100, tyrosine hydroxylase (TH) as a sympathetic marker, and vesicular acetylcholine transporter (VAChT) as a parasympathetic marker. The area of each marker-positive nerve was digitized and evaluated quantitatively. Double immunofluorescence for TH and VAChT was performed in selected cases. The expression of the secreted neurotrophins was also examined. S100-positive nerves were present in the cancer tissue in 94 of 129 cases (72.9%). Among them, TH-positive sympathetic nerves and/or VAChT-positive parasympathetic nerves were identified in 92 cases (97.9%), and 59 cases (62.8%) had TH/VAChT-co-expressing nerves. Double immunofluorescence revealed a mosaic pattern of sympathetic and parasympathetic fibers in co-expressing nerve bundles. The presence of autonomic nerves, regardless of their area, was significantly associated with aggressive histological features, advanced T/N classification, and a poor prognosis, with shorter disease-free and overall survival. There was an association between some tumor immune microenvironment-related markers and the autonomic nerve status, but not the latter and the secreted neurotrophin expression. This study suggests that autonomic nerves might play a role in the progression of SDC.

Stress-induced impairment of parasympathetic NO-mediated inhibition of sympathetic vasoconstriction in submucosal arteriole of rat rectum.

In the gastrointestinal tract, nitrergic inhibition of the arteriolar contractility has not been demonstrated. Here, we explored whether neurally-released nitric oxide (NO) inhibits sympathetic vasoconstrictions in the rat rectal arterioles. Changes in sympathetic vasoconstrictions and their nitrergic modulation in rats exposed to water avoidance stress (WAS, 10days, 1h per day) were also examined. In rectal submucosal preparations, changes in arteriolar diameter were monitored using video microscopy. In control or sham-treated rats, electrical field stimulation (EFS)-induced sympathetic vasoconstrictions were increased by the neuronal nitric oxide synthase (nNOS) inhibitor L-NPA (1μM) and diminished by the cyclic guanosine monophosphate-specific phosphodiesterase 5 (PDE5) inhibitor tadalafil (10nM). In phenylephrine-constricted, guanethidine-treated arterioles, EFS-induced vasodilatations were inhibited by the calcitonin gene-related peptide (CGRP) receptor antagonist BIBN-4096 (1μM) but not L-NPA. Perivascular nNOS-immunoreactive nitrergic fibres co-expressing the parasympathetic marker vesicular acetylcholine transporter (VAChT) were intermingled with tyrosine hydroxylase (TH)-immunoreactive sympathetic fibres expressing soluble guanylate cyclase (sGC), a receptor for NO. In WAS rats in which augmented sympathetic vasoconstrictions were developed, L-NPA failed to further increase the vasoconstrictions, while tadalafil-induced inhibition of the vasoconstrictions was attenuated. Phenylephrine- or α,β-methylene ATP-induced vasoconstrictions and acetylcholine-induced vasodilatations were unaltered by WAS. Thus, in arterioles of the rat rectal submucosa, NO released from parasympathetic nerves appears to inhibit sympathetic vasoconstrictions presumably by reducing sympathetic transmitter release. In WAS rats, sympathetic vasoconstrictions are augmented at least partly due to the diminished pre-junctional nitrergic inhibition of transmitter release without changing α-adrenoceptor or P2X-purinoctor mediated vasoconstriction and endothelium-dependent vasodilatation.

Activation of PACAP+ vagal motoneurons following remote ischemic pre-conditioning

The Dorsal Motor Nucleus of the Vagus nerve (DMV) provides parasympathetic innervation of the intrinsic cardiac nervous system (ICN), and it has been shown that DMV activity is required for the cardioprotection induced by remote ischemic pre-conditioning (RIPC) against the pathological effects of myocardial infarction. However, the mechanism behind the DMV’s cardioprotective effects is not well understood. Previous literature has shown that the DMV and the other vagal motor nuclei, the nucleus ambiguus (NA), innervate distinct cells within the ICN. DMV neurons project to many other organs in addition to the heart. The cardioprotective neuropeptide Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) has been found to be expressed in the fibers innervating the ICN, where it is co-localized with the parasympathetic marker, ChAT. While we have found PACAP to be expressed in cardiac-projecting DMV neurons, it is unknown whether these neurons are preferentially activated in response to RIPC. To assess the activity of these neurons following RIPC, we performed immunofluorescence staining of brainstem tissue containing DMV neurons for both PACAP, and c-FOS, a neuronal activity-dependent marker. We hypothesized that PACAP+ DMV neurons would have increased activity following RIPC, and therefore increased c-FOS intensity and increased co-localization with PACAP compared to sham control. Our results suggest that PACAP+ neurons in the DMV show increased activity following RIPC compared to sham, as defined by increased c-FOS fluorescence intensity and co-localization with PACAP. These results suggest that PACAP+ neurons are activated during the cardioprotective response to remote ischemic pre-conditioning. Funding was provided by the R01 HL161696 grant through National Heart, Lung, and Blood institute and the National Institutes of Health Common Fund SPARC Program Grant OT2OD030534. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Variation in coupling across neural and cardiac systems of regulation is linked to markers of anxiety risk in preschool.

Both cortical and parasympathetic systems are believed to regulate emotional arousal in the service of healthy development. Systemic coordination, or coupling, between putative regulatory functions begins in early childhood. Yet the degree of coupling between cortical and parasympathetic systems in young children remains unclear, particularly in relation to the development of typical or atypical emotion function. We tested whether cortical (ERN) and parasympathetic (respiratory sinus arrhythmia [RSA]) markers of regulation were coupled during cognitive challenge in preschoolers (N = 121). We found no main effect of RSA predicting ERN. We then tested children's typical and atypical emotion behavior (context-appropriate/context-inappropriate fear, anxiety symptoms, neuroendocrine reactivity) as moderators of early coupling in an effort to link patterns of coupling to adaptive emotional development. Negative coupling (i.e., smaller ERN, more RSA suppression or larger ERN, less RSA suppression) at age 3 was associated with greater atypical and less typical emotion behaviors, indicative of greater risk. Negative age 3 coupling was also visible for children who had greater Generalized Anxiety Disorder symptoms and blunted cortisol reactivity at age 5. Results suggest that negative coupling may reflect a maladaptive pattern across regulatory systems that is identifiable during the preschool years.

Human liver afferent and efferent nerves revealed by 3-D/Airyscan super-resolution imaging.

Neural regulation of hepatic metabolism has long been recognized. However, the detailed afferent and efferent innervation of the human liver has not been systematically characterized. This is largely due to the liver's high lipid and pigment contents, causing false-negative (light scattering and absorption) and false-positive (autofluorescence) results in in-depth fluorescence imaging. Here, to avoid the artifacts in three-dimensional (3-D) liver neurohistology, we embed the bleached human liver in the high-refractive-index polymer for tissue clearing and antifade 3-D/Airyscan super-resolution imaging. Importantly, using the paired substance P (SP, sensory marker) and PGP9.5 (pan-neuronal marker) labeling, we detect the sensory nerves in the portal space, featuring the SP+ varicosities in the PGP9.5+ nerve bundles/fibers, confirming the afferent liver innervation. Also, using the tyrosine hydroxylase (TH, sympathetic marker) labeling, we identify 1) condensed TH+ sympathetic nerves in the portal space, 2) extension of sympathetic nerves from the portal to the intralobular space, in which the TH+ nerve density is 2.6 ± 0.7-fold higher than that of the intralobular space in the human pancreas, and 3) the TH+ nerve fibers and varicosities contacting the ballooning cells, implicating potential sympathetic influence on hepatocytes with macrovesicular fatty change. Finally, using the vesicular acetylcholine transporter (VAChT, parasympathetic marker), PGP9.5, and CK19 (epithelial marker) labeling with panoramic-to-Airyscan super-resolution imaging, we detect and confirm the parasympathetic innervation of the septal bile duct. Overall, our labeling and 3-D/Airyscan imaging approach reveal the hepatic sensory (afferent) and sympathetic and parasympathetic (efferent) innervation, establishing a clinically related setting for high-resolution 3-D liver neurohistology.NEW & NOTEWORTHY We embed the human liver (vs. pancreas, positive control) in the high-refractive-index polymer for tissue clearing and antifade 3-D/Airyscan super-resolution neurohistology. The pancreas-liver comparison reveals: 1) sensory nerves in the hepatoportal space; 2) intralobular sympathetic innervation, including the nerve fibers and varicosities contacting the ballooning hepatocytes; and 3) parasympathetic innervation of the septal bile duct. Our results highlight the sensitivity and resolving power of 3-D/Airyscan super-resolution imaging in human liver neurohistology.

Abstract 17825: Heart Rate Fragmentation Analysis May Suggest Non-Autonomic Markers of Sudden Cardiac Death Risk in Adults With Williams-Beuren Syndrome

Background: Williams-Beuren syndrome (WBS) is a rare genetic disorder caused by a chromosomal microdeletion (7q11.23). It confers increased arrhythmia and sudden cardiac death (SCD) risk. Mechanisms underlying this risk remain obscure. We recently found HRV abnormalities in individuals with WBS that are known to correlate with sudden death risk in diabetes and following MI and stroke. Heart rate fragmentation (HRF) correlated with adverse CV events in some studies where HRV failed to identify high-risk subjects. Some argue that HRF quantifies non-autonomic CV modulators. We, therefore, sought to further explore non-autonomic modulators of cardiovascular disease by performing HRF analysis in a cohort of adults with WBS. Hypothesis: We hypothesize that those with WBS may exhibit increased sudden death risk from mechanisms not detected by conventional HRV measures. Aims: We aim to 1) Identify biomarkers that are predictive of SCD risk in WBS, and 2) Determine if HRF quantifies non-autonomic CV modulators. Methods: We performed HRF analyses on 24hr ECGs in subjects with WBS (n=18) and age- and sex-matched controls (n=18) enrolled in a prospective NIH study. HRF analyses include the percentage of inflection points (PIP), percentages of hard (PIP H ) and soft (PIP S ) inflection points, and the distribution of “words”, where W 0 ,W 1 ,W 2 , W 3 represent sequences of 4 beats with 0, 1, 2, or 3 inflection points. Inflection points were defined as a change in NN by more than 1/s, where ‘s’ is the sampling frequency. Mann-Whitney tests were used to compare HRF in subjects vs. controls. Spearman’s correlation was used to compare HRF to traditional HRV. Results: HRF markers (PIP, PIP S , and W 3 ) were significantly elevated in WBS subjects (P<0.003)(Fig 1A-C). PIP S and W 3 were negatively correlated with parasympathetic markers HF power and SD1 among WBS subjects (Fig 1D). Conclusion: HRF may quantify some non-autonomic modulators of sudden death risk in those with WBS.

Mastication stimuli regulate the heartbeat rate through rhythmic regulation by the hypothalamic-autonomic system; molecular and telemetric studies in weaning-stage rats.

Mastication stimuli have been demonstrated to affect memory function and autonomic nerve activity; however, this process has not been well studied during weaning compared to old age. Previously, we conducted molecular analyses of the thalamus and hippocampus to elucidate the mechanisms underlying this memory-enhancing effect in weaning-stage rats. In this study, we aimed to evaluate the effect of masticatory stimuli on the regulation of heartbeat rate (HR) through the hypothalamic-autonomic system. Three-week-old male rats were administered a powdered diet (P group) or chow-diet (C group) for 10 days. Thereafter, transcriptome analysis was performed. Vasopressin, cocaine-amphetamine-regulated transcript prepropeptide, corticotropin-releasing hormone, and thyrotropin-releasing hormone, which are involved in sympathetic activation of heart rate, were downregulated in the C group. Electrocardiograms were recorded continuously for 12 days under the same condition. Interestingly, rats in the C group had a significantly lower HR than those in the P group on day 11. We checked several parameters representing the autonomic regulation of HR. The C group had higher values for the high-frequency band integration of the HR power spectrum (parasympathetic marker) and root mean square successive difference of R-wave intervals (parasympathetic marker) relative to the P group. Such findings provide a molecular and physiological basis for understanding the regulation of cardiovascular function in response to masticatory stimuli in the autonomic nervous system.

Stellate Ganglion Sympathetic postganglionic efferent innervation in the flat-mount of the whole heart of rats: Anterograde Tracing

The autonomic nervous system (sympathetic and parasympathetic) plays an essential role in controlling cardiac functions. Previously, we used anterograde tracing to examine the vagal afferent and efferent (preganglionic) innervations of the normal heart, their anatomical remodeling and their functional changes in disease models of rats and mice. In addition, we used vesicular acetylcholine transporter (VAChT, a parasympathetic marker;) and tyrosine hydroxylase (TH, a sympathetic marker,) to determine the parasympathetic and sympathetic postganglionic innervation of the whole heart (atria and ventricles). Immunohistochemical labeling with TH is useful for determining the broad distribution of sympathetic efferent axons in the heart. However, it is difficult to distinguish its extrinsic and intrinsic origins using TH labeling. Furthermore, the topographical organization and morphological terminal structures of cardiac sympathetic postganglionic efferent axons from the stellate ganglia (SG) remains unknown. To address this we anterogradely labeled individual sympathetic postganglionic axons projecting to the heart, using tracer Dextran-Biotin microinjections into the right SG of Sprague-Dawley rats (male, n=6, 3-6 months). Fourteen days after the injection, animals were euthanized, and their hearts were dissected into the left/right atria (LA and RA) and ventricles and prepared as flat-mounts. The tracer-labeled axons were digitized and analyzed using The Neurolucida 3D tracing system and imaged using a Zeiss M2 Imager. We found that stellate sympathetic neurons had projections to the LA and RA and left and right ventricles. Individual sympathetic axons formed complex arbors of varicose neurites in the areas of the sinoatrial node (SAN) and atrioventricular node (AVN) as well as the other areas of the atria and throughout the ventricles. Sympathetic axons also innervated blood vessels. Using the Neurolucida Digitization and Tracer system, we determined the regional density and characterized different types of axons. Some axons formed relatively simple terminal structures with only a few branches, whereas other axons produced very complex terminals with extensive branching. For the first time, we anterogradely labeled the sympathetic postganglionic axons and characterized their terminal architecture in the whole heart. These results will provide an anatomical foundation for future study This study was supported by NIH HEAL/SPARC U01 NS113867-01 and NIH R15HL137143-01A1. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Pan-Cancer Characterization of Intratumoral Autonomic Innervation in 32 Cancer Types in the Cancer Genome Atlas.

Simple SummaryThere have been growing interests in the roles of intratumoral innervation of the autonomic nervous system (ANS) as a mechanism linking psychosocial stress, β-adrenergic signaling pathways, and poor cancer outcomes, and a potential target for therapeutic purpose. Our current knowledge is being limited by the few cancer types where intratumoral ANS have been studied; it remains to be determined the extent of this mechanism existing in different cancer types. Our study provided the first pan-cancer characterization of intratumoral innervation across 32 cancer types, and further, their relationships with tumor histopathological and molecular characteristics and survival outcomes. We found wide variations in intratumoral ANS expression both within and across cancer types. The association of ANS signatures with tumor histopathological characteristics and survival outcomes also varied by cancer type. Our findings suggest that the potential benefits of cancer therapies targeting β-adrenergic receptor-mediated stress signaling pathways are likely dependent on cancer type.Over the past two decades, multiple studies have demonstrated the important role that the autonomic nervous system (ANS) plays in tumorigenesis and cancer progression. However, the mechanisms by which this process occurs have only recently begun to be elucidated. Further, the extent of autonomic innervation in various cancer types and its effects on tumor molecular, immunological, and histopathological features, as well as on patient outcomes, are not yet fully characterized. In this study, we analyzed intratumoral ANS gene expression signatures, including overall intratumoral neuron growth and sympathetic and parasympathetic markers, across 32 cancer types using tumor transcriptomic and clinical annotation data available from The Cancer Genome Atlas (TCGA). Our analysis revealed wide variations in intratumoral ANS expression both within and across cancer types. The association of ANS signatures with tumor histopathological characteristics and survival outcomes also varied by cancer type. We found intratumoral ANS expression to be commonly correlated with angiogenesis, TGF-β signaling, and immunosuppression in the tumor microenvironment of many cancer types, which provide mechanistic insights into the involvement of intratumoral innervation in cancer development and progression. Our findings suggest that the potential benefits of cancer therapies targeting β-adrenergic receptor-mediated stress signaling pathways are likely dependent on cancer type.

High vagal tone predicts pulmonary vein reconnection after cryoballoon ablation for paroxysmal atrial fibrillation.

Pulmonary vein (PV) isolation is an established treatment for paroxysmal drug-refractory atrial fibrillation (AF). High parasympathetic tone and reconnection of PVs have demonstrated to be possible culprits of AF recurrence after ablation. Our aim was to investigate the association between parasympathetic tone and reconnected PVs in patients with paroxysmal AF. Consecutive patients who underwent a redo catheter ablation procedure for atrial tachyarrhythmia recurrence by means of 3D electroanatomic mapping with documentation of presence or absence of PVs reconnection following an initial procedure of cryoballoon (CB) ablation for symptomatic drug-refractory paroxysmal AF were screened for the study. A total of 92 patients were included, of whom 50 (54.35%) were males. Reconnected PVs were found in 64 (69%) patients. PVs reconnection could be predicted by DC (C-statistic = .770), by SDNNI (C-statistic = .714) and by absolute VLF power (C-statistic = .722), while right-sided PVs reconnection could be better predicted by DC (C-statistic = .848) and by SDNNI (C-statistic = .761). In multivariate binary logistic regression analysis, a DC value ≥6.45 ms and an absolute VLF power value ≥160 ms2 were associated with three times and five times higher odds of PVs reconnection, respectively. On a vein-per-vein analysis, absolute VLF power ≥160 ms2 was associated with three times higher odds, while reaching of -40°C within 60 s was associated with three times lower odds of PVs reconnection. High parasympathetic tonus accurately predicts PVs reconnection. On a vein-per-vein analysis, parasympathetic markers along with biophysical parameters predicted PVs reconnection. On a case-by-case analysis, parasympathetic markers were the only predictors of PVs reconnection, thus being a robust PVs reconnection prediction tool.

Stress and recovery in sports: Effects on heart rate variability, cortisol, and subjective experience

This study aimed to investigate (1) the time-variations and (2) the repeated measures relationship between training load (TL) and psychological and physiological parameters and performance. Data were collected around 12-weeks of training in fifteen national swimmers. Psychological states were assessed using the RESTQ-36-R-Sport Questionnaire and the Sport Emotion Questionnaire. Subjects collected four saliva samples throughout the day at 1) 7 a.m. immediately after waking, 2) 30 min after waking, 3) 60 min after waking, and 4) 8 p.m., allowing us to calculate the area under the curve with respect to ground (AUCg) and the sAA over cortisol ratio (AOC). Finally, heart rate variability was computed using a submaximal 5′-5′ running test. Time variations were analyzed throughout repeated measures ANOVA and repeated measures correlations were run using the “rmcorr” R package. Recovery-stress states and emotional markers showed quadratic curves, while parasympathetic markers showed linear trajectories over time. Significant associations over time were found between TL and recovery, stress, emotional states, lnRMSSD and the AOC. Taken together, these results provided evidence that psychological and physiological states do not follow the same dynamics (i.e., linear vs. quadratic vs. no variation) in the functional training periodization condition. Our study also provided evidence that recovery-stress states, emotional states, lnRMSSD, and the AOC were of interest due to their intra-individual associations around the time with TL.

Validity of Commonly Used Heart Rate Variability Markers of Autonomic Nervous System Function

Background: Despite strong reservations regarding the validity of a number of heart rate variability (HRV) measures, these are still being used in recent studies. Aims: We aimed to compare the reactivity of ostensible sympathetic HRV markers (low and very low frequency [LF and VLF]) to that of electrodermal activity (EDA), an exclusively sympathetic marker, in response to cognitive and orthostatic stress, investigate the possibility of LF as a vagal-mediated marker of baroreflex modulation, and compare the ability of HRV markers of parasympathetic function (root mean square of successive differences [RMSSD] and high frequency [HF]) to quantify vagal reactivity to cognitive and orthostatic stress. Results: None of the purported sympathetic HRV markers displayed a reactivity that correlated with electrodermal reactivity. LF (ms²) reactivity correlated with the reactivity of both RMSSD and HF during baroreflex modulation. RMSSD and HF indexed the reactivity of the parasympathetic nervous system under conditions of normal breathing; however, RMSSD performed better as a marker of vagal activity when the task required breathing changes. Conclusions: Neither LF (in ms² or normalized units [nu]) nor VLF represent cardiac sympathetic modulation of the heart. LF (ms²) may reflect vagally mediated baroreflex cardiac effects. HRV linear analysis therefore appears to be restricted to the determination of vagal influences on heart rate. With regard to HRV parasympathetic markers, this study supports the suggestion that HRV frequency domain analyses, such as HF, should not be used as an index of vagal activity in study tasks where verbal responses are required, as these responses may induce respiratory changes great enough to distort HF power.

Innervation of the entire internal anal sphincter in a mouse model of Hirschsprung's disease: a first report.

Impaired function of the internal anal sphincter (IAS) may be implicated in postoperative obstructed defecation (POD) that may complicate Hirschsprung's disease (HD) patients. While innervation of part of the IAS in HD has been reported, accurate details based on anatomic landmarks that can explain the clinical morbidity seen in POD are lacking, and there appear to be no studies that specifically document the innervation of the "entire" IAS in HD. We used endothelin receptor-B knockout mice to represent HD (HD-mice) and C57B6 wild mice as controls (C-mice) to investigate the innervation of the entire IAS to assess the pathophysiology of POD experimentally. The end-point of the longitudinal muscle layer was used to define the border between the IAS and the circular muscle layer (CML). Specimens of anorectum from HD- and C-mice were immunostained with PGP 9.5 and S100 as general nerve markers, nNOS and VIP as parasympathetic nerve markers, TH as a sympathetic nerve marker, and calretinin as a reliable diagnostic marker for HD. Immunostained cells/fibers were quantified using ImageJ. On fluorescence microscopy, PGP 9.5, nNOS, and calretinin were significantly lower in the IAS of HD-mice than in C-mice (p < 0.05, respectively), while there were no significant differences between HD-mice and C-mice for S100, VIP, or TH. We are the first to confirm that the expression of histochemical markers of innervation is abnormal throughout the "entire" IAS in HD-mice. Application of this finding may be beneficial for preventing POD and requires further research.

A12830 The Effect Of A Very Low Calorie Diet On The Heart Rate Variability In Patients Newly Diagnosed With Type 2 Diabetes Mellitus

Objectives: To study the effect of an 8-week very low calorie diet on the heart rate variability in patients newly diagnosed with type 2 diabetes mellitus. Methods: We conducted a non-randomized single-arm clinical trial over a period of 8 months in patients newly diagnosed with type 2 diabetes mellitus, naïve to anti- diabetic medication, having a body mass index of at least 25 kg/m2 and HbA1c between 47.5- 80.3 mmol/mol (6.5–9.5%). Intervention consisted of daily consumption of 600 + /- 50 kcal meals over a period of 8 weeks. Before and after intervention we measured body fat composition by bioimpedance, blood pressure, fasting blood sugar, glycated haemoglobin, lipid profile, liver function tests, serum creatininaemia and full blood count. We also performed a resting ECG and a 24- hour ECG recording, from where parameters of the heart rate variability (HRV) were obtained: SDNN, SDANN, LF, PNN50%, RMSSD, HF, LF/HF. Results: We included 18 patients (10 females) aged 53 (45–57) years, newly diagnosed with diabetes and with 51.0 mmol/mol baseline HbA1c. The intervention induced the following decrements: 3.4% BMI, 10.7 % fat mass, 46.2% fasting blood glucose, 14.7% HbA1c and 14.3% triglycerides. We also found significant increments in HRV parameters as follows: Sympathetic markers: SDNN 27.3%, SDANN 35.3%, LF 458%; Parasympathetic markers: PNN50% 95.1%, RMSSD 231%, HF 867%. There was also significant improvement in sympatho-vagal balance, indicated by a 32.6% decrease in LF/HF ratio. Conclusion: A very low calorie diet is feasible, well tolerated, and accepted, and results in tremendous metabolic and cardiovascular improvements after 8 weeks, in a Cameroonian population with newly diagnosed type 2 diabetes mellitus.

Site-dependent differences in the composite fibers of male pelvic plexus branches: an immunohistochemical analysis of donated elderly cadavers

BackgroundAlthough the pelvic autonomic plexus branches are considered to be a mixture of sympathetic and parasympathetic nerves, little is known regarding the composite fibers of the pelvic plexus branches. This study aimed to investigate the immunohistochemical features of sympathetic and parasympathetic nerves in the pelvic autonomic plexus branches.MethodsUsing 10 donated elderly male cadavers, the detailed topohistology of nerve fibers at and around the bladder, seminal vesicle, prostate, and rectum was examined. Neuronal nitric oxide synthase (nNOS) and vasoactive intestinal polypeptide (VIP) were used as parasympathetic nerve markers; tyrosine hydroxylase (TH) was used as a sympathetic nerve marker. The myenteric plexus of the colon was utilized as a positive control.ResultsMost nerve fibers in the bladder, seminal vesicle, prostate, and rectum were both nNOS- and TH-positive. Thus, pelvic plexus branches were classified into two types: 1) triple-positive mixed nerves (nNOS+, VIP+, TH+, thick myelinated fibers + or -) and 2) double-positive mixed nerves (nNOS+, VIP-, TH+, thick myelinated fibers + or -). Notably, triple-positive nerves were localized within the posterosuperior part of the plexus (near the rectum) and travelled anteroinferiorly toward the posterolateral corner of the prostate. The posteriorly and inferiorly located nerves were predominantly composed of parasympathetic, rather than sympathetic, fibers. In contrast, nerve fibers within and along the bladder and seminal vesicle contained either no or few VIP-positive nerves. These superiorly located nerves were characterized by clear sympathetic nerve dominance.ConclusionsThe nerves of the pelvic plexus branches were clearly classified into nerves around the bladder and seminal vesicle (VIP-negative) and nerves around the prostate (VIP-positive). Although nNOS- and VIP-positive nerve fibers are candidate cavernous nerves, cavernous nerve identity cannot be definitively concluded for these nerves in the periprostatic region.

Elite swimmers' internal markers trajectories in ecological training conditions.

This study examined the trajectories of elite swimmers' recovery-stress states and cardiac vagal-related markers during a 3-month training period preceding the national championship and their within-person relationships with perceived control. A Multilevel Growth Curve Analysis (MGCA) approach was used with 21 male elite swimmers. Four waves of assessments of psychological (stress, recovery, perceived control) and physiological (heart rate recovery, heart rate variability) markers were completed during a 3month training preparation leading to a major competition. Results of MGCA revealed (a) a significant positive linear effect of time (ie, linear increase over time) and a significant negative quadratic effect of time (ie, inverted U shape over time) on perceived stress whereas the opposite pattern of results was observed for perceived recovery; and (b) a significant positive linear effect of time for nHRR60. Both at level 1 (within-person level of analysis) and 2 (between-person level of analysis), perceived control was (a) positively associated with athletes' perceived recovery and parasympathetic markers (ie, MeanRR; pNN50); and (b) negatively related to swimmers' perceived stress. Results also indicated that within-person interactions of perceived control with time reached significance for general recovery and HRV. Finally, within-person interaction of perceived control with squared time reached significance for subjective sport-specific and total stress. Overall, this study provided insights into the key role played by perceived control on both psychological and physiological markers related to recovery-stress states' levels during the 3-month training period preceding the national championship.

Co-expression of vasoactive intestinal peptide and protein gene product 9.5 surrounding the lumen of human Schlemm's canal

Previous studies of aqueous humor outflow have focused primarily on resistance at the trabecular meshwork (TM), and little is known about the function of Schlemm's canal (SC). Here, we aimed to investigate whether SC is innervated by the peripheral nervous system. Ten eye specimens from eight donors were processed for histological analysis. CD31 was used to identify SC, after which we used protein gene product (PGP) 9.5 as a marker to detect nerve fibers around SC. We then characterized the nerves by double staining for PGP9.5 and sympathetic nerve markers, such as tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DβH), or the parasympathetic marker vasoactive intestinal peptide (VIP), as well as sensory nerve marker calcitonin gene-related peptide (CGRP) and vesicular glutamate transporter 2 (VGLUT2). Immunohistochemistry and immunofluorescence were also performed to detect the expression of γ-epithelial Na+ channel (γ-ENaC) in SC. We found that different markers were expressed in the anterior chamber angle, with the luminal surface of SC were only positive stained for PGP9.5, VIP, and γ-ENaC. CGRP and VGLUT2 were expressed in TM and scleral spur (SS), whereas TH and DβH were absent in both TM and SC. Furthermore, PGP9.5 was co-expressed with VIP and γ-ENaC in the region surrounding the SC as well as in SS. Our findings indicate that the peripheral nerves anatomically spread in the tissues around the SC and the local nerve fibers may be parasympathetic or sensory rather than sympathetic.

The influence of citrus aurantium and caffeine complex versus placebo on the cardiac autonomic response: a double blind crossover design

BackgroundThe purpose of this study was to examine the resting cardiac autonomic nervous system’s response to the ingestion of a complex containing Citrus aurantium + Caffeine (CA + C) and its influence on recovery following a high-intensity anaerobic exercise bout in habitual caffeine users.MethodsTen physically active males (25.1 ± 3.9 years; weight 78.71 ± 9.53 kg; height 177.2 ± 4.6 cm; body fat 15.5 ± 3.13%) participated in this study, which consisted of two exhaustive exercise protocols in a randomized crossover design. On each visit the participants consumed either a CA + C (100 mg of CA and 100 mg of C) or placebo (dextrose) capsule. After consumption, participants were monitored throughout a 45-min ingestion period, then completed a repeated Wingate protocol, and were then monitored throughout a 45-min recovery period. Cardiac autonomic function (Heart Rate (HR) and Heart Rate Variability (HRV)) and plasma epinephrine (E) and norepinephrine (NE) were taken at four different time points; Ingestion period: baseline (I1), post-ingestion period (I2); Recovery period: immediately post-exercise (R1), post-recovery period (R2). Heart rate variability was assessed in 5-min increments.ResultsA repeated measures ANOVA revealed significant time-dependent increases in HR, sympathetic related markers of HRV, and plasma E and NE at I2 only in the CA + C trial (p < 0.05); however, no meaningful changes in parasympathetic markers of HRV were observed. Participants recovered in a similar time-dependent manner in all markers of HRV and catecholamines following the PLA and CA + C trials.ConclusionThe consumption of CA + C results in an increase of sympathetic activity during resting conditions without influencing parasympathetic activity. CA + C provides no influence over cardiac autonomic recovery.

Cranial parasympathetic activation induces autonomic symptoms but no cluster headache attacks.

Background Low frequency (LF) stimulation of the sphenopalatine ganglion (SPG) may increase parasympathetic outflow and provoke cluster headache (CH) attacks in CH patients implanted with an SPG neurostimulator. Methods In a double-blind randomized sham-controlled crossover study, 20 CH patients received LF or sham stimulation for 30 min on two separate days. We recorded headache characteristics, cephalic autonomic symptoms (CAS), plasma levels of parasympathetic markers such as pituitary adenylate cyclase-activating polypeptide-38 (PACAP38) and vasoactive intestinal peptide (VIP), and mechanical detection and pain thresholds as a marker of sensory modulation. Results In the immediate phase (0-60 min), 16 (80%) patients experienced CAS after LF stimulation, while nine patients (45%) reported CAS after sham ( p = 0.046). We found no difference in induction of cluster-like attacks between LF stimulation (n = 7) and sham stimulation (n = 5) ( p = 0.724). There was no difference in mechanical detection and pain thresholds, and in PACAP and VIP plasma concentrations between LF and sham stimulation ( p ≥ 0.162). Conclusion LF stimulation of the SPG induced autonomic symptoms, but no CH attacks. These data suggest that increased parasympathetic outflow is not sufficient to induce CH attacks in patients. Study protocol ClinicalTrials.gov registration number NCT02510729.

Respiratory Sinus Arrhythmia in Cognitive Behavioral Therapy for Posttraumatic Stress Symptoms in Children: Preliminary Treatment and Gender Effects.

Cognitive behavioral therapy (CBT) is an efficacious treatment for posttraumatic stress disorder (PTSD) symptoms, but the effect of CBT on physiological indicators is largely unknown. Respiratory sinus arrhythmia (RSA) is an established parasympathetic marker of self-regulatory capacity and stress responsivity. The present study tested if and how resting RSA and RSA reactivity changed following treatment among a sample of children (n = 48) who experienced at least one traumatic event and presented with PTSD symptoms. RSA reactivity was measured in response to personalized trauma-related scripts. Results indicated that changes in RSA after treatment were dependent on pretreatment resting levels of RSA, with individuals with high and low pretreatment resting RSA levels appearing to converge over time in both resting RSA and RSA reactivity by the 3-month follow up. Specific to RSA reactivity, a sex difference was evident, as following treatment, females showed less RSA withdrawal whereas males showed more RSA withdrawal. PTSD symptoms were significantly reduced after CBT but symptom change was not associated with pretreatment resting RSA levels. Overall, these results suggest that there may be multiple physiological patterns within children with PTSD and the direction of the physiological changes after CBT may depend on initial differences in resting RSA levels.