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Background Bioactive lipids play an important role in insulin secretion and sensitivity, contributing to the pathophysiology of type 2 diabetes (T2D). This study aimed to identify novel lipid species associated with incident T2D in a nested case–control study within a long-term prospective Chinese community-based cohort with a median follow-up of ~ 16 years. Methods Plasma samples from 196 incident T2D cases and 196 age- and sex-matched non-T2D controls recruited from the Hong Kong Cardiovascular Risk Factor Prevalence Study (CRISPS) were first analyzed using untargeted lipidomics. Potential predictive lipid species selected by the Boruta analysis were then verified by targeted lipidomics. The associations between these lipid species and incident T2D were assessed. Effects of novel lipid species on insulin secretion in mouse islets were investigated. Results Boruta analysis identified 16 potential lipid species. After adjustment for body mass index (BMI), triacylglycerol/high-density lipoprotein (TG/HDL) ratio and the presence of prediabetes, triacylglycerol (TG) 12:0_18:2_22:6, TG 16:0_11:1_18:2, TG 49:0, TG 51:1 and diacylglycerol (DG) 18:2_22:6 were independently associated with increased T2D risk, whereas lyso-phosphatidylcholine (LPC) O-16:0, LPC P-16:0, LPC O-18:0 and LPC 18:1 were independently associated with decreased T2D risk. Addition of the identified lipid species to the clinical prediction model, comprised of BMI, TG/HDL ratio and the presence of prediabetes, achieved a 3.8% improvement in the area under the receiver operating characteristics curve (AUROC) (p = 0.0026). Further functional study revealed that, LPC O-16:0 and LPC O-18:0 significantly potentiated glucose induced insulin secretion (GSIS) in a dose-dependent manner, whereas neither DG 18:2_22:6 nor TG 12:0_18:2_22:6 had any effect on GSIS. Conclusions Addition of the lipid species substantially improved the prediction of T2D beyond the model based on clinical risk factors. Decreased levels of LPC O-16:0 and LPC O-18:0 may contribute to the development of T2D via reduced insulin secretion.

Background/Aims The relationship between animal exposure and irritable bowel syndrome (IBS) is debated. Epidemiological studies have shown that atopy is more prevalent in IBS patients and vice versa. We set out to examine the association between animal danders sensitization and IBS-like symptoms in atopic patients. Methods We recruited 69 consecutive atopic patients from the allergy clinic of a tertiary hospital. Subjects completed validated bowel questionnaires, underwent skin prick test, blood was collected for serum total immunoglobulin E, and ImmunoCAP immune solid-phase allergen chip (ISAC) IgE multiplex assay. Results Twenty-eight (41.0%) atopic patients fulfilled the Rome III IBS criteria (atopy-IBS). There were no differences in gender, age, pet ownership, total serum IgE, or food allergen sensitization between atopy-IBS group and atopy-non-IBS group. We found that atopy- IBS group had significantly higher number of positive skin prick test for cat dander (64.3% vs 24.4%, P < 0.001), dog dander (64.3% vs 41.5%, P = 0.015) and weed pollens (32.1% vs 14.6%, P = 0.050) compared to atopy-non-IBS group. Out of 112 components from 51 allergen sources (both aeroallergen and food allergens), only Fel d1 (a major cat dander antigen) IgE is significantly higher in atopy-IBS group than atopy-non-IBS group (21.4% vs 2.4%, P = 0.029). Majority of atopy-IBS patients had mixed-type IBS. Conclusions We demonstrated an association between animal danders sensitization, in particular cat dander sensitization, and IBS-like symptoms in atopic patients. Future studies are needed to explore the relationship between aeroallergen and functional gastrointestinal disorders. Sensitization may be related to the pathophysiology of IBS or it could be that we are missing aeroallergen-induced gut allergy. (J Neurogastroenterol Motil 2020;26:267-273)

Background and aim: Gastrointestinal manifestations of the coronavirus disease 2019 (COVID-19) pandemic may mimic irritable bowel syndrome (IBS), and social distancing measures may affect IBS patients negatively. We aimed to study the impact of COVID-19 on respondents with self-reported IBS. Methods: We conducted an anonymized survey from May to June 2020 in 33 countries. Knowledge, attitudes, and practices on personal hygiene and social distancing as well as psychological impact of COVID-19 were assessed. Statistical analysis was performed to determine differences in well-being and compliance to social distancing measures between respondents with and without self-reported IBS. Factors associated with improvement or worsening of IBS symptoms were evaluated. Results: Out of 2704 respondents, 2024 (74.9%) did not have IBS, 305 (11.3%) had self-reported IBS, and 374 (13.8%) did not know what IBS was. Self-reported IBS respondents reported significantly worse emotional, social, and psychological well-being compared with non-IBS respondents and were less compliant to social distancing measures (28.2% vs 35.3%, P = 0.029); 61.6% reported no change, 26.6% reported improvement, and 11.8% reported worsening IBS symptoms. Higher proportion of respondents with no change in IBS symptoms were willing to practice social distancing indefinitely versus those who deteriorated (74.9% vs 51.4%, P = 0.016). In multivariate analysis, willingness to continue social distancing for another 2-3 weeks (vs longer period) was significantly associated with higher odds of worsening IBS. Conclusion: Our study showed that self-reported IBS respondents had worse well-being and compliance to social distancing measures than non-IBS respondents. Future research will focus on occupational stress and dietary changes during COVID-19 that may influence IBS.

Exercise is an effective strategy for diabetes management but is limited by the phenomenon of exercise resistance (i.e., the lack of or the adverse response to exercise on metabolic health). Here, in 39 medication-naive men with prediabetes, we found that exercise-induced alterations in the gut microbiota correlated closely with improvements in glucose homeostasis and insulin sensitivity (clinicaltrials.gov entry NCT03240978). The microbiome of responders exhibited an enhanced capacity for biosynthesis of short-chain fatty acids and catabolism of branched-chain amino acids, whereas those of non-responders were characterized by increased production of metabolically detrimental compounds. Fecal microbial transplantation from responders, but not non-responders, mimicked the effects of exercise on alleviation of insulin resistance in obese mice. Furthermore, a machine-learning algorithm integrating baseline microbial signatures accurately predicted personalized glycemic response to exercise in an additional 30 subjects. These findings raise the possibility of maximizing the benefits of exercise by targeting the gut microbiota.