Abnormal functional connectivity of the reward circuit associated with early satiety in patients with postprandial distress syndrome.

Postprandial distress syndrome (PDS) is the most common functional dyspepsia (FD) subtype. Early satiety is one of the cardinal symptoms of the PDS subtype in FD patients. The heterogeneity of symptoms in FD patients hampered therapy for patients based on specific symptoms, necessitating a symptom-based understanding of the pathophysiology of FD. To investigate the correlation between reward circuit and symptom severity of PDS patients, seed (Nucleus accumbens, NAc, a key node in the reward circuit) based resting-state functional connectivity (FC) was applied in the neuroimaging data analysis. The results demonstrated that the patients with PDS manifested strengthened FC between NAc and the caudate, putamen, pallidum, amygdala, hippocampus, thalamus, anterior cingulate cortex (ACC), and insula. Moreover, the FC between NAc and ACC, insula, thalamus, and hippocampus exhibited significant positive associations with symptom severity. More importantly, the strengthened FC between NAc and the ACC, insula, amygdala, and hippocampus were found associated with the early satiety symptom of patients with PDS. This study indicated that the altered FC of reward circuit regions may play a role in the pathophysiology of patients with PDS, and some of the aberrant NAc-based FC within the reward circuit were more related to the early satiety of patients with PDS. These findings improve our symptom-based understanding of the central pathophysiology of FD, lay the groundwork for an objective diagnosis of FD, and shed light on the precise prescription for treating FD based on symptoms.

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Neuroimaging technology provides objective and visualized research tool to study the mechanisms of acupuncture effects. Building on a systematic review of previous clinical studies on acupuncture treatment for functional dyspepsia using neuroimaging technology, this paper summarizes and synthesizes past researches from 4 aspects： acupoint-specific effects, factors influencing the effects, different physiological responses, and predictive factors for acupuncture efficacy. It suggests that acupuncture treatment for FD involves central integration with disease-targeted (acupuncture treatment can target and regulate abnormal brain functional activity patterns in patients with FD), meridian-specific (stimulation of specific acupuncture points along the stomach meridian can significantly regulate abnormal brain functional activity patterns in FD patients), and dynamic conditional features(the effects of acupuncture treatment for FD are influenced by multiple factors). Lastly, considering the current research status, this paper outlines prospects in terms of research subjects, influencing factors, and result validation, aiming to provide references for future in-depth research.

Clinical-functional brain connectivity signature predicts longitudinal symptom improvement after acupuncture treatment in patients with functional dyspepsia.

Whilst acupuncture has been shown to be an effective treatment for functional dyspepsia (FD), its efficacy varies significantly among patients. Knowing beforehand how each patient responds to acupuncture treatment will facilitate the ability to produce personalized prescriptions, therefore, improving acupuncture efficacy. The objective of this study was to construct the prediction model, based on the clinical-neuroimaging signature, to forecast the individual symptom improvement of FD patients following a 4-week acupuncture treatment and to identify the critical predictive features that could potentially serve as biomarkers for predicting the efficacy of acupuncture for FD. Clinical-functional brain connectivity signatures were extracted from samples in the training-test set (100 FD patients) and independent validation set (60 FD patients). Based on these signatures and support vector machine algorithms, prediction models were developed in the training test set, followed by model performance evaluation and predictive features extraction. Subsequently, the external robustness of the extracted predictive features in predicting acupuncture efficacy was evaluated by the independent validation set. The developed prediction models possessed an accuracy of 88% in predicting acupuncture responders, as well as an R2 of 0.453 in forecasting symptom relief. Factors that contributed significantly to stronger responsiveness of patients to acupuncture therapy included higher resting-state functional connectivity associated with the orbitofrontal gyrus, caudate, hippocampus, and anterior insula, as well as higher baseline scores of the Symptom Index of Dyspepsia and shorter durations of the condition. Furthermore, the robustness of these features in predicting the efficacy of acupuncture for FD was verified through various machine learning algorithms and independent samples and remained stable in univariate and multivariate analyses. These findings suggest that it is both feasible and reliable to predict the efficacy of acupuncture for FD based on the pre-treatment clinical-neuroimaging signature. The established prediction framework will promote the identification of suitable candidates for acupuncture treatment, thereby improving the efficacy and reducing the cost of acupuncture for FD.

Altered resting-state brain activity in functional dyspepsia patients: a coordinate-based meta-analysis.

Background: Neuroimaging studies have identified aberrant activity patterns in multiple brain regions in functional dyspepsia (FD) patients. However, due to the differences in study design, these previous findings are inconsistent, and the underlying neuropathological characteristics of FD remain unclear. Methods: Eight databases were systematically searched for literature from inception to October 2022 with the keywords "Functional dyspepsia" and "Neuroimaging." Thereafter, the anisotropic effect size signed the differential mapping (AES-SDM) approach that was applied to meta-analyze the aberrant brain activity pattern of FD patients. Results: A total of 11 articles with 260 FD patients and 202 healthy controls (HCs) were included. The AES-SDM meta-analysis demonstrated that FD patients manifested increased activity in the bilateral insula, left anterior cingulate gyrus, bilateral thalamus, right precentral gyrus, left supplementary motor area, right putamen, and left rectus gyrus and decreased functional activity in the right cerebellum compared to the HCs. Sensitivity analysis showed that all these above regions were highly reproducible, and no significant publication bias was detected. Conclusion: The current study demonstrated that FD patients had significantly abnormal activity patterns in several brain regions involved in visceral sensation perception, pain modulation, and emotion regulation, which provided an integrated insight into the neuropathological characteristics of FD.

Aberrant resting-state functional connectivity and topological properties of the subcortical network in functional dyspepsia patients.

Functional dyspepsia (FD) is a disorder of gut-brain interaction. Previous studies have demonstrated a wide range of abnormalities in functional brain activity and connectivity patterns in FD. However, the connectivity pattern of the subcortical network (SCN), which is a hub of visceral information transmission and processing, remains unclear in FD patients. The study compared the resting-state functional connectivity (rsFC) and the global and nodal topological properties of SCN between 109 FD patients and 98 healthy controls, and then explored the correlations between the connectivity metrics and clinical symptoms in FD patients. The results demonstrated that FD patients manifested the increased rsFC in seventeen edges among the SCN, decreased small-worldness and local efficiency in SCN, as well as increased nodal efficiency and nodal degree centrality in the anterior thalamus than healthy controls (p < 0.05, false discovery rate corrected). Moreover, the rsFC of the right anterior thalamus-left nucleus accumbens edge was significantly correlated with the NDSI scores (r = 0.255, p = 0.008, uncorrected) and NDLQI scores (r = -0.241, p = 0.013, uncorrected), the nodal efficiency of right anterior thalamus was significantly correlated with NDLQI scores (r = 0.204, p = 0.036, uncorrected) in FD patients. This study indicated the abnormal rsFC pattern, as well as global and nodal topological properties of the SCN, especially the bilateral anterior thalamus in FD patients, which enhanced our understanding of the central pathophysiology of FD and will lay the foundation for the objective diagnosis of FD and the development of new therapies.

Therapeutic effects and central mechanism of acupuncture and moxibustion for treating functional dyspepsia: study protocol for an fMRI-based randomized controlled trial.

BACKGROUND: Functional dyspepsia (FD) is one of the most common functional gastrointestinal disorders, with a high prevalence and significant influence on the quality of life (QoL). Either acupuncture or moxibustion is effective for dyspepsia, which is confirmed by both ancient documents and modern research. However, the therapeutic advantage and underlying mechanism between acupuncture and moxibustion for FD remain unclear. METHODS: This randomized controlled fMRI trial aims to (i) evaluate the therapeutic advantages of acupuncture and moxibustion treatment for FD, (ii) investigate the similarities and differences in cerebral activity elicited by acupuncture and moxibustion, and (iii) analyze the possible correlations between brain responses and clinical variables thus to explore the potential central mechanism of acupuncture and moxibustion for treating FD. Ninety-two FD patients will be randomly assigned to either the acupuncture group or the moxibustion group in a 1:1 ratio. Twenty sessions of acupuncture or moxibustion treatment over 4 weeks will be performed on each patient. The short form Leeds Dyspepsia Questionnaire, the Nepean Dyspepsia Index, etc., are used to evaluate the therapeutic effects. The heart rate variability will be analyzed to investigate the autonomic nerve function. Thirty-six FD patients in each group will be randomly selected for the fMRI scan to detect cerebral activity changes. DISCUSSION: We expect the results will deepen our knowledge on the clinical value and underlying mechanism of acupuncture and moxibustion and provide a reference for a better selection of interventions for treating FD. TRIAL REGISTRATION: Chinese Clinical Trial Registry ( www.chictr.org.cn ) ChiCTR2100049496. Registered on 2 August 2021.