Vagal Nerve Stimulation-Modulation of the Anti-Inflammatory Response and Clinical Outcome in Psoriatic Arthritis or Ankylosing Spondylitis.

OBJECTIVES: The vagal nerve exerts an essential pathway in controlling the cholinergic anti-inflammatory reflex. Thus, the study is aimed at investigating the acute effect of a noninvasive transcutaneous vagus nerve stimulation on clinical disease activity and systemic levels of inflammation in patients with psoriatic arthritis or ankylosing spondylitis. METHODS: Twenty patients with psoriatic arthritis (PsA) and 20 patients with ankylosing spondylitis (AS) were included and stimulated bilaterally with a handheld vagal nerve stimulator for 120 seconds 3 times a day for 5 consecutive days. All patients were in remission. Cardiac vagal tone, clinical scores, CRP, and cytokine levels were assessed. RESULTS: In PsA and AS, decreased heart rate was observed, confirming compliance. Furthermore, in PsA, a clear reduction of clinical disease activity associated with a 20% reduction in CRP was shown. In AS, a reduction in interferon-γ, interleukin- (IL-) 8, and 10 was shown. No side effects were described. CONCLUSION: This open-label study provides support for an anti-inflammatory effect of transcutaneous vagus nerve stimulation in patients with psoriatic arthritis and ankylosing spondylitis. The modulated immune response and reduced disease activity and CRP-levels raise the fascinating possibility of using neuromodulation as an add-on to existing pharmacological treatments.

Short-term transcutaneous non-invasive vagus nerve stimulation may reduce disease activity and pro-inflammatory cytokines in rheumatoid arthritis: results of a pilot study.

Objective: Rheumatoid arthritis (RA) is a chronic, autoimmune, inflammatory disease. Studies suggest that pro-inflammatory cytokines may be attenuated by the vagus nerve through the cholinergic anti-inflammatory pathway. We aimed to evaluate the anti-inflammatory effects of short-term transcutaneous non-invasive vagus nerve stimulation (n-VNS) applied to the cervical vagus nerve in patients with RA. Method: We conducted a single-centre, open-label, preliminary proof-of-concept study of n-VNS in two cohorts of participants with RA: one with high disease activity (n = 16) and one with low disease activity (n = 20). Disease Activity Score based on 28-joint count-C-reactive protein (DAS28-CRP), cardiac vagal tone, and pro-inflammatory cytokines were measured at baseline and after 1 and 4 days of n-VNS. Results: In the high disease activity group, n-VNS resulted in reductions in DAS28-CRP (4.1 to 3.8, p = 0.02), CRP (8.2 to 6 mg/mL, p = 0.01), and interferon-γ (29.8 to 22.5 pg/mL, p = 0.02). In the low disease activity group, there was no effect on DAS28-CRP, and n-VNS was associated with a decrease in cardiac vagal tone (p = 0.03) and a reduction in interleukin-10 (0.8 to 0.6 pg/mL, p = 0.02). Participants with high disease activity had lower baseline cardiac vagal tone than those with low disease activity (3.6 ± 2 vs 4.9 ± 3 linear vagal scale, p = 0.03). Cardiac vagal tone was negatively associated with DAS28-CRP (r = -0.37, p = 0.03). Overall, n-VNS was well tolerated. Conclusion: This study provides preliminary support for an anti-inflammatory effect of n-VNS in patients with RA. These findings warrant further investigation in larger placebo-controlled trials.

Regional gastrointestinal pH profile is altered in patients with type 1 diabetes and peripheral neuropathy.

BACKGROUND: Gastrointestinal (GI) symptoms, such as nausea and bloating, are common in people with type 1 diabetes (T1DM). Autonomic dysfunction can lead to changes in the GI secreto-motor function which can be associated with GI symptom development. We hypothesized that regional pH profiles in T1DM differs from health and would be associated with objective physiological/clinical markers. METHODS: Forty-seven T1DM with confirmed diabetic sensory peripheral neuropathy and 41 healthy age-matched subjects underwent standardized wireless motility capsule testing. T1DM completed the gastroparesis cardinal symptom index (GCSI) and the gastrointestinal symptom rating scale. Disease duration, glycemic control, insulin usage, and 24-hour heart rate variability testing were evaluated. KEY RESULTS: In comparison to healthy subjects, gastric, and large bowel median pH were lower in T1DM (1.8 ± 1.6 vs 2.9 ± 1.5, P = 0.001 and 6.7 ± 0.6 vs 7.0 ± 0.5, P = 0.003, respectively). Additionally, change in pH across the pylorus was lower while change in pH across the ileocecal junction was higher in T1DM (5.2 ± 1.5 vs 5.8 ± 0.5, P = 0.003 and 1.8 ± 0.4 vs 1.3 ± 0.4, P < 0.0001, respectively). No difference was found in small bowel median pH. Gastric median pH was associated with small bowel transit time (r = 0.30, P = 0.049). Change in pH across the pylorus was negatively associated with fasting glycose (r = -0.35, P = 0.027). Small bowel median pH was associated with nausea (r = 0.42, P = 0.005) and small bowel transit time (r = 0.48, P = 0.0007). Large bowel median pH was associated with nausea (r = 0.35, P = 0.018) and the total GCSI score (r = 0.34, P = 0.023). CONCLUSIONS AND INFERENCES: The GI pH profile in T1DM with DSPN is different from healthy subjects. Changes in pH profile may have important therapeutic implications and influence pharmacotherapeutic bioavailability.

Regional gastrointestinal contractility parameters using the wireless motility capsule: inter-observer reproducibility and influence of age, gender and study country.

BACKGROUND: The wireless motility capsule concurrently measures temperature, pH and pressure as it traverses the gastrointestinal tract. AIMS: To describe normative values for motility/contractility parameters across age, gender and testing centres. METHODS: Healthy participants underwent a standardised wireless motility capsule assessment following an overnight fast and consumption of a meal of known nutritional content. Traces were divided into regions of interest and analysed using 2 software packages (MotiliGI and GIMS Data Viewer). Inter-observer agreement was independently assessed by 2 investigators. RESULTS: Normative data for motility/contractility parameters (maximum amplitude, mean peak amplitude, contraction frequency and motility index) are presented for 107 individuals (62 male, median age 40 years, range 18-78). MotiliGI-Gastric, small bowel and colonic maximal contraction amplitude correlated with age (r = .24, P = .01; r = .22, P = .02; and r = .2, P = .04 respectively). Small bowel motility index was higher in females than males (150.4 ± 12 vs 122 ± 7.6, P = .04). Inter-observer agreement was excellent for transit times, pH and contractility/motility parameters. GIMS Data viewer-Gastric, small bowel and colonic loge motility index correlated with the respective area under the contraction curve, total contractions, sum of amplitudes and contraction frequency (all r>.35, P < .0003) but not with transit times. CONCLUSIONS: Our analysis provides normative data for motility/contractility parameters. Log motility index summarises a number of measures. In future, the measurement of contractile activity with the wireless motility capsule may potentially aid in the diagnosis of disease states such as visceral myopathic disorders.

Vagal influences in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic immune-mediated inflammatory disease with a prevalence of 0.5-1% in Western populations. Conventionally, it is treated with therapeutic interventions that include corticosteroids, disease-modifying anti-rheumatic drugs, and biological agents. RA exerts a significant socio-economic burden and despite the use of existing treatments some patients end up with disabling symptoms. The autonomic nervous system (ANS) is a brain-body interface that serves to regulate homeostasis by integrating the external environment with the internal milieu. The main neural substrate of the parasympathetic branch of the ANS is the vagus nerve (VN). The discovery of the role of the ANS and the VN in mediating and dampening the inflammatory response has led to the proposal that modulation of neural circuits may serve as a valuable therapeutic tool. Recent studies have explored the role of the VN in this inflammatory reflex and have provided evidence that stimulation may represent a novel new therapeutic intervention. Accumulating evidence suggests that modulation of the parasympathetic tone results in a broad physiological multi-level response, including decreased pro-inflammatory cytokine response in terms of tumour necrosis factor-α, interleukin-1 (IL-1), and IL-6, and may result in an enhanced macrophage switch from M1 to M2 cells and potentially an increased level of the anti-inflammatory cytokine IL-10. Therefore, therapeutic electrical modulation of the VN may serve as an alternative, non-pharmacological, neuroimmunomodulatory intervention in RA in the future. This review gives a focused introduction to the mechanistic link between the ANS and the immune system.

Cardiac vagal tone, a non-invasive measure of parasympathetic tone, is a clinically relevant tool in Type 1 diabetes mellitus.

AIMS: To compare a novel index of parasympathetic tone, cardiac vagal tone, with established autonomic variables and to test the hypotheses that (1) cardiac vagal tone would be associated with established time and frequency domain measures of heart rate and (2) cardiac vagal tone would be lower in people with Type 1 diabetes than in a matched healthy cohort and lower still in people with established neuropathy. METHODS: Cardiac vagal tone is a validated cardiometrically derived index of parasympathetic tone. It is measured using a standard three-lead electrocardiogram which connects, via Bluetooth, to a smartphone application. A 5-min resting recording of cardiac vagal tone was undertaken and observational comparisons were made between 42 people with Type 1 diabetes and peripheral neuropathy and 23 without peripheral neuropathy and 65 healthy people. In those with neuropathy, 24-h heart rate variability values were compared with cardiac vagal tone. Correlations between cardiac vagal tone and clinical variables were also made. RESULTS: Cardiac vagal tone was lower in people with established neuropathy and Type 1 diabetes in comparison with healthy participants [median (interquartile range) linear vagal scale 3.4 (1.6-5.5 vs 7.0 (5.5-9.6); P < 0.0001]. Cardiac vagal tone was positively associated with time (r = 0.8, P < 0.0001) and frequency domain markers of heart rate variability (r = 0.75, P < 0.0001), representing established measures of parasympathetic function. Cardiac vagal tone was negatively associated with age (r=-0.32, P = 0.003), disease duration (r=-0.43, P < 0.0001) and cardiovascular risk score (r=-0.32, P = 0.006). CONCLUSIONS: Cardiac vagal tone represents a convenient, clinically relevant method of assessing parasympathetic nervous system tone, potentially facilitating the earlier identification of people with Type 1 diabetes who should undergo formal autonomic function testing.

Gastrointestinal disorders in joint hypermobility syndrome/Ehlers-Danlos syndrome hypermobility type: A review for the gastroenterologist.

BACKGROUND: Joint hypermobility syndrome (JHS)/Ehlers-Danlos syndrome hypermobility type (EDS-HT) is the most common hereditary non-inflammatory disorder of connective tissue, characterized by a wide range of symptoms, mainly joint hyperextensibility and musculoskeletal symptoms. A majority of patients also experiences gastrointestinal (GI) symptoms. Furthermore, JHS/EDS-HT has specifically been shown to be highly prevalent in patients with functional GI disorders, such as functional dyspepsia and irritable bowel syndrome. PURPOSE: The aim of this review was to examine the nature of GI symptoms and their underlying pathophysiology in JHS/EDS-HT. In addition, we consider the clinical implications of the diagnosis and treatment of JHS/EDS-HT for practicing clinicians in gastroenterology. Observations summarized in this review may furthermore represent the first step toward the identification of a new pathophysiological basis for a substantial subgroup of patients with functional GI disorders.

Effects of eosinophilic oesophagitis on quality of life in an adult UK population: a case control study.

Eosinophilic oesophagitis (EoE) is a chronic immune-mediated esophageal disease, characterized by symptoms related to esophageal dysfunction and histologically by eosinophil predominant inflammation. Current evidence for an adverse impact on quality of life (QoL) is conflicting and there are no data from a UK population regarding QoL. We conducted a prospective cross-sectional observational study using the Short Form-36 Health Survey, Hospital Dysphagia/Odynophagia Questionnaire, and the EoE Adult Quality of Life Questionnaire to assess QoL and severity of dysphagia in EoE patients, compared to age and gender matched healthy control subjects. Data were also collected on comorbidity and medication use. Eighty-eight subjects were recruited (44 patients). Patients had higher rates of antihistamine and topical (swallowed) corticosteroid use. Physical QoL did not differ between patients and controls, although patients did report a statistically significant lower mental QoL, with small absolute magnitude of difference. Patients reported higher dysphagia scores and these were negatively correlated with both physical and mental QoL. Higher rates of dysphagia and medication use in patients may among other things account for lower mental QoL. However, a higher rate of dysphagia in patients is not associated with a reduced physical QoL. Our findings are of clinical value, particularly when a new diagnosis of EoE is made, as clinicians can reassure patients that their general physical health should not be greatly affected by the diagnosis. Moreover, it may also be useful for patients to be aware that EoE may have an impact on their mental health, but this effect is likely to be small. We therefore advocate education and reassurance in this respect for all patients at diagnosis.

Transcutaneous cervical vagal nerve stimulation modulates cardiac vagal tone and tumor necrosis factor-alpha.

The vagus nerve is a central component of cholinergic anti-inflammatory pathways. We sought to evaluate the effect of bilateral transcutaneous cervical vagal nerve stimulation (t-VNS) on validated parameters of autonomic tone and cytokines in 20 healthy subjects. 24 hours after t-VNS, there was an increase in cardiac vagal tone and a reduction in tumor necrosis factor-α in comparison to baseline. No change was seen in blood pressure, cardiac sympathetic index or other cytokines. These preliminary data suggest that t-VNS exerts an autonomic and a subtle antitumor necrosis factor-α effect, which warrants further evaluation in larger controlled studies.