Duodenal Anaerobutyricum soehngenii infusion stimulates GLP-1 production, ameliorates glycaemic control and beneficially shapes the duodenal transcriptome in metabolic syndrome subjects: a randomised double-blind placebo-controlled cross-over study

OBJECTIVE

Although gut dysbiosis is increasingly recognised as a pathophysiological component of metabolic syndrome (MetS), the role and mode of action of specific gut microbes in metabolic health remain elusive. Previously, we identified the commensal butyrogenic Anaerobutyricum soehngenii to be associated with improved insulin sensitivity in subjects with MetS. In this proof-of-concept study, we investigated the potential therapeutic effects of A. soehngenii L2-7 on systemic metabolic responses and duodenal transcriptome profiles in individuals with MetS.

DESIGN

In this randomised double-blind placebo-controlled cross-over study, 12 male subjects with MetS received duodenal infusions of A. soehngenii/ placebo and underwent duodenal biopsies, mixed meal tests (6 hours postinfusion) and 24-hour continuous glucose monitoring.

RESULTS

A. soehngenii treatment provoked a markedly increased postprandial excursion of the insulinotropic hormone glucagon-like peptide 1 (GLP-1) and an elevation of plasma secondary bile acids, which were positively associated with GLP-1 levels. Moreover, A. soehngenii treatment robustly shaped the duodenal expression of 73 genes, with the highest fold induction in the expression of regenerating islet-protein 1B (REG1B)-encoding gene. Strikingly, duodenal REG1B expression positively correlated with GLP-1 levels and negatively correlated with peripheral glucose variability, which was significantly diminished in the 24 hours following A. soehngenii intake. Mechanistically, Reg1B expression is induced upon sensing butyrate or bacterial peptidoglycan. Importantly, A. soehngenii duodenal administration was safe and well tolerated.

CONCLUSIONS

A single dose of A. soehngenii improves peripheral glycaemic control within 24 hours; it specifically stimulates intestinal GLP-1 production and REG1B expression. Further studies are needed to delineate the specific pathways involved in REG1B induction and function in insulin sensitivity.

TRIAL REGISTRATION NUMBER

NTR-NL6630.

Faecal microbiota transplantation halts progression of human new-onset type 1 diabetes in a randomised controlled trial

OBJECTIVE

Type 1 diabetes (T1D) is characterised by islet autoimmunity and beta cell destruction. A gut microbiota-immunological interplay is involved in the pathophysiology of T1D. We studied microbiota-mediated effects on disease progression in patients with type 1 diabetes using faecal microbiota transplantation (FMT).

DESIGN

Patients with recent-onset (<6 weeks) T1D (18-30 years of age) were randomised into two groups to receive three autologous or allogenic (healthy donor) FMTs over a period of 4 months. Our primary endpoint was preservation of stimulated C peptide release assessed by mixed-meal tests during 12 months. Secondary outcome parameters were changes in glycaemic control, fasting plasma metabolites, T cell autoimmunity, small intestinal gene expression profile and intestinal microbiota composition.

RESULTS

Stimulated C peptide levels were significantly preserved in the autologous FMT group (n=10 subjects) compared with healthy donor FMT group (n=10 subjects) at 12 months. Small intestinal Prevotella was inversely related to residual beta cell function (r=-0.55, p=0.02), whereas plasma metabolites 1-arachidonoyl-GPC and 1-myristoyl-2-arachidonoyl-GPC levels linearly correlated with residual beta cell preservation (rho=0.56, p=0.01 and rho=0.46, p=0.042, respectively). Finally, baseline CD4 +CXCR3+T cell counts, levels of small intestinal Desulfovibrio piger and CCL22 and CCL5 gene expression in duodenal biopsies predicted preserved beta cell function following FMT irrespective of donor characteristics.

CONCLUSION

FMT halts decline in endogenous insulin production in recently diagnosed patients with T1D in 12 months after disease onset. Several microbiota-derived plasma metabolites and bacterial strains were linked to preserved residual beta cell function. This study provides insight into the role of the intestinal gut microbiome in T1D.

TRIAL REGISTRATION NUMBER

NTR3697.

Treatment with Anaerobutyricum soehngenii: a pilot study of safety and dose-response effects on glucose metabolism in human subjects with metabolic syndrome

Dysbiosis of the intestinal microbiota has been implicated in insulin resistance, although evidence regarding causality in humans is scarce. We performed a phase I/II dose-finding and safety study on the effect of oral intake of the anaerobic butyrogenic strain Anaerobutyricum soehngenii on glucose metabolism in 24 subjects with metabolic syndrome. We found that treatment with A. soehngenii was safe and observed a significant correlation between the measured fecal abundance of administered A. soehngenii and improvement in peripheral insulin sensitivity after 4 weeks of treatment. This was accompanied by an altered microbiota composition and a change in bile acid metabolism. Finally, we show that metabolic response upon administration of A. soehngenii (defined as improved insulin sensitivity 4 weeks after A. soehngenii intake) is dependent on microbiota composition at baseline. These data in humans are promising, but additional studies are needed to reproduce our findings and to investigate long-term effects, as well as other modes of delivery.

Abstract 32: Hypercholesterolemia-induced Priming of Hematopoietic Stem and Progenitor Cells Aggravates Atherosclerosis

During homeostasis hematopoietic stem and progenitor stem cells (HSPCs) give rise to lymphoid and myeloid cells as well as platelets and erythrocytes. However, during chronic inflammatory conditions hematopoiesis is often skewed towards the myeloid lineage, thereby potentially aggravating the ongoing inflammation. Here we investigated the effects of hypercholesterolemia on HSPCs during atherogenesis.

Hypercholesterolemia increased HSPCs, defined as Lin - Sca1 + cKit - , in the bone marrow (BM) of LDLr -/- mice by 253.1%. The number of granulocyte-monocyte progenitors, BM granulocytes and BM monocytes was increased by 18.1%, 34.8% and 13.2%, respectively. In accordance, the myeloid colony forming potential of hypercholesterolemic BM was increased by 25.8%. Peripheral blood monocytes and granulocytes were increased by 203.0% and 161.1%, respectively.

Competitive bone marrow transplantations (cBMT) in which we compared the effects of normo- vs. hypercholesterolemia primed HSPCs confirmed that the hypercholesterolemic microenvironment activates HSPCs, as reflected by a 26.5% increased reconstitution of peripheral blood leukocytes 10 weeks after the cBMT. Moreover, hypercholesterolemia-primed, and not normocholesterolemia-primed HSPCs acquired an enhanced propensity to generate myeloid cells, especially granulocytes and Ly6C high monocytes, even under long-term normocholesterolemic conditions in the recipient animals. cBMT demonstrated that hypercholesterolemia-induced activation of HSPCs increased atherosclerosis in LDLr -/- mice by 122.1% and increased CD45.1 + plaque leukocytes by 76.1%. Macrophages differentiated from hypercholesterolemia-primed BM produced increased levels of TNFα (+21.3%), IL6 (+17.4%) and MCP1 (+10.5%) compared to their normocholesterolemic counterparts, demonstrating that hypercholesterolemia-induced priming of HSPCs increased the inflammatory phenotype of their mature offspring.

These results demonstrate that hypercholesterolemia-induced priming of HSPCs aggravates atherosclerosis by skewing hematopoiesis towards the pro-inflammatory myeloid lineages. Inhibition of this pro-inflammatory differentiation pathway on HSPC level has the potential to reduce atherosclerosis.

HDL protein composition alters from proatherogenic into less atherogenic and proinflammatory in rheumatoid arthritis patients responding to rituximab

OBJECTIVE

An atherogenic lipid profile is an established risk factor for cardiovascular (CV) diseases. Interestingly, high inflammatory states as present in rheumatoid arthritis (RA) are associated with unfavourable lipid profile. Data about effects of novel immunomodulating agents as rituximab (RTX) on lipid profile are limited. Therefore, changes in lipids in RTX treated RA patients were evaluated.

METHODS

In 49 consecutive RTX treated RA patients, serum and EDTA plasma samples were collected at baseline, 1, 3 and 6 months. In these samples, lipid and levels were assessed to determine changes in time. Surface-enhanced laser desorption/ionisation time-of-flight (SELDI-TOF) MS analysis was performed in six good and six non-responding RA patients to study functional high density lipoprotein (HDL) protein composition changes in time.

RESULTS

In the total group (n=49), the atherogenic index decreased from 4.3 to 3.9 (∼9%) after 6 months. Testing for effect modification revealed a difference in the effect on lipid levels between responders and non-responders upon RTX (p<0.001). ApoB to ApoA-I ratios decreased significantly (∼9%) in good responding (n=32) patients. SELDI-TOF MS analysis revealed a significant decrease in density of mass charge (m/z) marker 11743, representing a decrease in serum amyloid A, in good responding patients.

CONCLUSION

This study indicates beneficial effects on cholesterol profile upon RTX treatment along with improvement of disease activity. Proteomic analysis of the HDL particle reveals composition changes from proatherogenic to a less proatherogenic composition during 6 months RTX treatment. Whether these HDL particle alterations during immunotherapies result in a lower CV event rate remains to be established.