BACKGROUND: According to the current Parkinson\'s Disease (PD) pathogenesis hypotheses, the vagus nerve (VN) is essential for disease development. It has been identified as a main entry point for misfolded α-synuclein to the central nervous system, and surgical vagotomy appears to limit disease progress both in animal models and in humans. A recent approach tried to assess VN size in PD patients via neck ultrasonography, but the clinical value of this method is yet to be established.
BACKGROUND: A systematic search of the MEDLINE, Scopus, and Web of Science databases was conducted, and 12 case- -control studies were included. Meta-analysis revealed a modest reduction in VN size in PD (effect size - 0.79 SD (95%CI [-1.34, -0.25] p = 0.004)). The atrophy was more pronounced on the right side, and the nerve was smaller in females. In PD patients, VN reduction correlated with cardiac parasympathetic function decline and with advances in motor ratings. The discrimination potential for PD diagnosis, and any association with other non-motor domains, remains unclear.
CONCLUSIONS: VN atrophy in PD could be detected by ultrasound imaging. However, the clinical significance of this phenomenon has yet to be clarified. Size reduction is not readily apparent and is individually variable. However, it may be considered a promising means to improve early PD diagnosis and the recognition of autonomic dysfunction.
CONCLUSIONS: With more extensive research, VN sonography could provide useful evidence regarding disease origins. Imaging should be performed together with a profound clinical assessment and biomarker testing to establish the role to be played by this method in future practice.

We present a case report describing an unexpected anomaly encountered during a total thyroidectomy for a patient with papillary carcinoma of the left lobe of the thyroid with retrosternal extension. Intraoperatively, we discovered that the left lobe of the thyroid gland had extended posteriorly, invading the carotid space and displacing the carotid sheath anteriorly. The vagus nerve was identified as a cord-like structure abutting the anterior surface of the tumor, in close relation to the strap muscles. This case highlights the importance of careful dissection and identification of anatomical structures during thyroidectomy procedures to avoid inadvertent nerve injury. We discuss the significance of meticulous dissection-wide exposure and advocate for greater awareness and vigilance among surgeons.

Non-recurrent laryngeal nerve (NRLN) is an anatomic variation seen in about 0.52-0.7% patients, generally on right side. It exits the vagus nerve having a direct route to the larynx, unlike usual recurrent laryngeal nerve, supplying intrinsic laryngeal muscles except cricothyroid. It is sited over left side on extremely rare occasions, that is, 0.04% of the cases. Some cases of NRLN co-exists with aberrant right subclavian artery which courses behind the esophagus, also known as \'arteria lusoria\'. Here we present a case of 60-years old patient, diagnosed as goiter presented to us in june 2023 at the department of head and neck surgery at a tertiary care setup of Karachi Pakistan. Intra-operatively, non-recurrent nerve was encountered, whose association was found with arteria lusoria, observed in pre-operative CT-scan. The nerve was saved and no post-operative complications were seen in patient. The association of arteria lusoria in this case emphasize its importance in predicting NRLN via pre-operative imaging techniques which can prevent its injury intra-operatively.

(1) Background: We examined the effect of the acute administration of olive oil (EVOO), linseed oil (GLO), soybean oil (SO), and palm oil (PO) on gastric motility and appetite in rats. (2) Methods: We assessed food intake, gastric retention (GR), and gene expression in all groups. (3) Results: Both EVOO and GLO were found to enhance the rate of stomach retention, leading to a decrease in hunger. On the other hand, the reduction in food intake caused by SO was accompanied by delayed effects on stomach retention. PO caused an alteration in the mRNA expression of NPY, POMC, and CART. Although PO increased stomach retention after 180 min, it did not affect food intake. It was subsequently verified that the absence of an autonomic reaction did not nullify the influence of EVOO in reducing food consumption. Moreover, in the absence of parasympathetic responses, animals that received PO exhibited a significant decrease in food consumption, probably mediated by lower NPY expression. (4) Conclusions: This study discovered that different oils induce various effects on parameters related to food consumption. Specifically, EVOO reduces food consumption primarily through its impact on the gastrointestinal tract, making it a recommended adjunct for weight loss. Conversely, the intake of PO limits food consumption in the absence of an autonomic reaction, but it is not advised due to its contribution to the development of cardiometabolic disorders.

Negative psychological states impact immunity by altering the gut microbiome. However, the relationship between brain states and microbiome composition remains unclear. We show that Brunner\'s glands in the duodenum couple stress-sensitive brain circuits to bacterial homeostasis. Brunner\'s glands mediated the enrichment of gut Lactobacillus species in response to vagus nerve stimulation. Cell-specific ablation of the glands markedly suppressed Lactobacilli counts and heightened vulnerability to infection. In the forebrain, we mapped a vagally mediated, polysynaptic circuit connecting the central nucleus of the amygdala to Brunner\'s glands. Chronic stress suppressed central amygdala activity and phenocopied the effects of gland lesions. Conversely, excitation of either the central amygdala or parasympathetic vagal neurons activated Brunner\'s glands and reversed the effects of stress on the gut microbiome and immunity. The findings revealed a tractable brain-body mechanism linking psychological states to host defense.

BACKGROUND: A recent meta-analysis revealed that vagally mediated heart rate variability (vmHRV; a biomarker of emotion regulation capacity) significantly decreases in the luteal phase of the menstrual cycle. As two follow-up studies suggest, these vmHRV decreases are driven primarily by increased luteal progesterone (P4). However, analyses also revealed significant interindividual differences in vmHRV reactivity to the cycle, which is in line with longstanding evidence for interindividual differences in mood sensitivity to the cycle. The present study begins to investigate whether these interindividual differences in vmHRV cyclicity can explain who is at higher risk of showing premenstrual emotional changes. We expected a greater degree of midluteal vmHRV decrease to be predictive of a greater premenstrual increase in negative affect.
METHODS: We conducted an observational study with a naturally cycling community sample (N = 31, M = 26.03 years). Over a span of six weeks, participants completed (a) daily ratings of negative affect and (b) counterbalanced lab visits in their ovulatory, midluteal, and perimenstrual phases. Lab visits were scheduled based on positive ovulation tests and included assessments of baseline vmHRV and salivary ovarian steroid levels.
RESULTS: In line with previous research, multilevel models suggest that most of the sample shows ovulatory-to-midluteal vmHRV decreases which, however, were not associated with premenstrual emotional changes. Interestingly, it was only the subgroup with luteal increases in vmHRV whose negative affect markedly worsened premenstrually and improved postmenstrually.
CONCLUSIONS: The present study begins to investigate cyclical changes in vmHRV as a potential biomarker of mood sensitivity to the menstrual cycle. The results demonstrate a higher level of complexity in these associations than initially expected, given that only atypical midluteal increases in vmHRV are associated with greater premenstrual negative affect. Potential underlying mechanisms are discussed, among those the possibility that luteal vmHRV increases index compensatory efforts to regulate emotion in those with greater premenstrual negative affect. However, future studies with larger and clinical samples and more granular vmHRV assessments should build on these findings and further explore associations between vmHRV cyclicity and menstrually related mood changes.

Increased sympathetic and reduced parasympathetic nerve activity is associated with disease progression and poor outcomes in patients with chronic heart failure. The demonstration that markers of autonomic imbalance and vagal dysfunction, such as reduced heart rate variability and baroreflex sensitivity, hold prognostic value in patients with chronic heart failure despite modern therapies encourages the research for neuromodulation strategies targeting the vagus nerve. However, the approaches tested so far have yielded inconclusive results. This review aims to summarize the current knowledge about the role of the parasympathetic nervous system in chronic heart failure, describing the pathophysiological background, the methods of assessment, and the rationale, limits, and future perspectives of parasympathetic stimulation either by drugs or bioelectronic devices.

The past decade has seen an explosion in our knowledge about the interactions between gut microbiota, the central nervous system, and the immune system. The gut-brain axis has recently gained much attention due to its role in regulating host physiology. This review explores recent findings concerning potential pathways linking the gut-brain axis to the initiation, pathophysiology, and development of neurological disorders. Our objective of this work is to uncover causative factors and pinpoint particular pathways and therapeutic targets that may facilitate the translation of experimental animal research into practical applications for human patients. We highlight three distinct yet interrelated mechanisms: (1) disruptions of both the intestinal and blood-brain barriers, (2) persistent neuroinflammation, and (3) the role of the vagus nerve.

BACKGROUND: Several single-center studies proposed utility of vagus nerve (VN) ultrasound for detecting disease severity, autonomic dysfunction, and bulbar phenotype in amyotrophic lateral sclerosis (ALS). However, the resulting body of literature shows opposing results, leaving considerable uncertainty on the clinical benefits of VN ultrasound in ALS.
METHODS: Relevant studies were identified up to 04/2024 and individual patient data (IPD) obtained from the respective authors were pooled with a so far unpublished cohort (from Munich). An IPD meta-analysis of 109 patients with probable or definite ALS (El Escorial criteria) and available VN cross-sectional area (CSA) was performed, with age, sex, ALS Functional Rating Scale-revised (ALSFRS-R), disease duration, and bulbar phenotype as independent variables.
RESULTS: Mean age was 65 years (± 12) and 47% of patients (± 12) had bulbar ALS. Mean ALSFRS-R was 38 (± 7), and mean duration was 18 months (± 18). VN atrophy was highly prevalent [left: 67% (± 5), mean CSA 1.6mm2 (± 0.6); right: 78% (± 21), mean CSA 1.8 mm2 (± 0.7)]. VN CSA correlated with disease duration (mean slope: left - 0.01; right - 0.01), but not with ALSFRS-R (mean slope: left 0.004; mean slope: right - 0.002). Test accuracy for phenotyping bulbar vs. non-bulbar ALS was poor (summary receiver operating characteristic area under the curve: left 0.496; right 0.572).
CONCLUSIONS: VN atrophy in ALS is highly prevalent and correlates with disease duration, but not with ALSFRS-R. VN CSA is insufficient to differentiate bulbar from non-bulbar ALS phenotypes. Further studies are warranted to analyze the link between VN atrophy, autonomic impairment, and survival in ALS.

After esophagectomy, an imbalanced inflammatory response increases the risk of postoperative morbidity. The vagus nerve modulates local and systemic inflammatory responses, but its pulmonary branches are transected during esophagectomy as part of the oncological resection, which may account for the high incidence of postoperative (pulmonary) complications. This study investigated the effect of electrical vagus nerve stimulation (VNS) on lipopolysaccharide (LPS)-induced lung injury in rats. Rats (n = 60) were randomly assigned to a non-vagotomy or cervical vagotomy group, with VNS or without (NOSTIM). There were four non-vagotomy groups: NOSTIM and bilateral VNS with 100, 50, or 10 µA. The four vagotomy groups were NOSTIM and VNS with fixed amplitude (50 µA) bilaterally before (VNS-50-before) or after bilateral vagotomy (VNS-50-after), or unilaterally (left) before ipsilateral vagotomy (VNS-50-unilaterally). LPS was administered intratracheally after surgery. Pulmonary function, pro-inflammatory cytokines in serum, broncho-alveolar lavage fluid (BALF), and histopathological lung injury (LIS) were assessed 180 min post-procedure. In non-vagotomized rats, neutrophil influx in BALF following intra-tracheal LPS (mean 30 [± 23]; P = 0.075) and LIS (mean 0.342 [± 0.067]; P = 0.142) were similar after VNS-100, compared with NOSTIM. VNS-50 reduced neutrophil influx (23 [± 19]; P = 0.024) and LIS (0.316 [± 0.093]; P = 0.043). VNS-10 reduced neutrophil influx (15 [± 6]; P = 0.009), while LIS (0.331 [± 0.053]; P = 0.088) was similar. In vagotomized rats, neutrophil influx (52 [± 37]; P = 0.818) and LIS (0.407 [SD ± 0.037]; P = 0.895) in VNS-50-before were similar compared with NOSTIM, as well as in VNS-50-after (neutrophils 30 [± 26]; P = 0.090 and LIS 0.344 [± 0.053]; P = 0.073). In contrast, VNS-50-unilaterally reduced neutrophil influx (26 [± 10]; P = 0.050) and LIS (0.296 [± 0.065]; P = 0.005). Systemic levels of cytokines TNF-α and IL-6 were undetectable in all groups. Pulmonary function was not statistically significantly affected. In conclusion, VNS limited influx of neutrophils in lungs in non-vagotomized rats and may attenuate LIS. Unilateral VNS attenuated lung injury even after ipsilateral vagotomy. This effect was absent for bilateral VNS before and after bilateral vagotomy. It is suggested that the effect of VNS is dependent on (partially) intact vagus nerves and that the level of the vagotomy during esophagectomy may influence postoperative pulmonary outcomes.