The systemic immune network in recent onset type 1 diabetes: central role of interleukin-1 receptor antagonist (DIATOR Trial)

Metabolite-based dietary supplementation in human type 1 diabetes is associated with microbiota and immune modulation

BACKGROUND

Short-chain fatty acids (SCFAs) produced by the gut microbiota have beneficial anti-inflammatory and gut homeostasis effects and prevent type 1 diabetes (T1D) in mice. Reduced SCFA production indicates a loss of beneficial bacteria, commonly associated with chronic autoimmune and inflammatory diseases, including T1D and type 2 diabetes. Here, we addressed whether a metabolite-based dietary supplement has an impact on humans with T1D. We conducted a single-arm pilot-and-feasibility trial with high-amylose maize-resistant starch modified with acetate and butyrate (HAMSAB) to assess safety, while monitoring changes in the gut microbiota in alignment with modulation of the immune system status.

RESULTS

HAMSAB supplement was administered for 6 weeks with follow-up at 12 weeks in adults with long-standing T1D. Increased concentrations of SCFA acetate, propionate, and butyrate in stools and plasma were in concert with a shift in the composition and function of the gut microbiota. While glucose control and insulin requirements did not change, subjects with the highest SCFA concentrations exhibited the best glycemic control. Bifidobacterium longum, Bifidobacterium adolescentis, and vitamin B7 production correlated with lower HbA1c and basal insulin requirements. Circulating B and T cells developed a more regulatory phenotype post-intervention.

CONCLUSION

Changes in gut microbiota composition, function, and immune profile following 6 weeks of HAMSAB supplementation were associated with increased SCFAs in stools and plasma. The persistence of these effects suggests that targeting dietary SCFAs may be a mechanism to alter immune profiles, promote immune tolerance, and improve glycemic control for the treatment of T1D.

TRIAL REGISTRATION

ACTRN12618001391268. Registered 20 August 2018, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375792 Video Abstract.

Evaluating the effects of sedentary behaviour on plantar skin health in people with diabetes

BACKGROUND

Diabetes-Related Foot Ulcers (DRFUs) are a common and devastating consequence of Diabetes Mellitus and are associated with high morbidity, mortality, social and economic costs. Whilst peak plantar pressures during gait are implicated cited as a major contributory factor, DRFU occurrence has also been associated with increased periods of sedentary behaviour. The present study was designed aimed to assess the effects of sitting postures on plantar tissue health.

METHODS

After a period of acclimatisation, transcutaneous oxygen tensions (T_CPO₂) and inflammatory cytokines (IL-1α and IL-1RA) were measured at the dorsal and plantar aspects of the forefoot before, during and after a 20-min period of seated-weight-bearing in participants with diabetes (n = 11) and no diabetes (n = 10). Corresponding interface pressures at the plantar site were also measured.

RESULTS

During weight-bearing, participants with diabetes showed increases in tissue ischaemia which were linearly correlated proportional to plantar pressures (Pearson's r = 0.81; p < 0.05). Within the healthy group, no such correlation was evident (p > 0.05). There were also significant increases in post seated weight-bearing values for ratio for IL-1α and IL-1RA, normalised to total protein, post seated weight-bearing in participants with diabetes compared to healthy controls.

CONCLUSION

This study shows that prolonged sitting may be detrimental to plantar skin health. It highlights the need to further examine the effects of prolonged sitting in individuals, who may have a reduced tolerance to loading in the plantar skin and soft tissues.

A phase I study of anti-inflammatory therapy with rilonacept in adolescents and adults with type 1 diabetes mellitus

BACKGROUND

The innate immune system may be activated around the time of diagnosis of type 1 diabetes (T1D). Components of this system, including cytokines such as interleukin-1β (IL-1β) represent potential therapeutic targets for disease modifying therapy.

OBJECTIVE

We conducted a phase 1 trial of rilonacept, an IL-1 cytokine trap, in patients with T1D.

SUBJECTS AND METHODS

Thirteen T1D patients (10 males) with median age (interquartile range, IQR) of 17 years (16-18), a median (IQR) of 5 months (5-7) since diagnosis. Rilonacept was administered subcutaneously for 26 weeks. Incidence of infections was the primary end-point.

RESULTS

There were 85 adverse events; 13 were Grade 2, of which 9 (8 infectious) were judged "possibly related" to the drug. The mean (SD) C-peptide on 2-hour mixed meal tolerance tests decreased from 0.87 (0.42) to 0.59 (0.29) ng/mL (P = .01 by paired t test) during 6 months on treatment. Hemoglobin A1c (HbA1c) increased from 6.8 (1.1) to 7.3 (1.1) (P = .05), but there was not a significant change in daily insulin dose (0.41 ± 0.23 to 0.47 ± 0.18), or in insulin dose-adjusted HbA1c (IDAA1c, 8.4 ± 1.8 to 9.0 ± 1.5). Subjects in "remission," defined as HbA1c <6.5 and a total daily insulin dose <0.5 units/kg/24 h, decreased from 5 to 4. There were no significantly differentially expressed genes in peripheral blood leukocytes before and after rilonacept.

CONCLUSIONS

Rilonacept treatment for 6 months is well-tolerated in individuals with T1D of recent onset, but is unlikely to be efficacious as a single agent in preserving beta cell function.

MiR-30a targets IL-1α and regulates islet functions as an inflammation buffer and response factor

Diabetes is an inflammatory disease. Inflammation plays an important role in islet functions. However, the exact mechanisms by which inflammation affects islet functions remain unclear. In this study, we investigated the regulatory effects of miR-30a on inflammation and islet functions. The results indicate that miR-30a serves as an inflammation-resolving buffer factor by targeting interleukin 1a (IL-1α) in immune cells and in islet cells, which might play an important role in inflammation homeostasis. miR-30a ameliorates islet functions in an inflammatory micro-environment by targeting the IL-1α/nuclear factor kappa B (NFKB) p65 subunit (p65)/p62 (SQSTM1)/insulin axis, which can be developed into a novel antidiabetic approach. miR-30a serves as a promising inflammation-response biomarker in inflammatory diseases and is possibly activated by the toll-like receptor 4 (TLR4)/IL-1α/NFKB pathways. However, the exact molecular mechanisms by which miR-30a regulates inflammation and islet functions as well as the potential applications in transitional medicine require further elucidation.

The role of inflammation in intravenous immune globulin-mediated hemolysis

Intravenous immune globulin (IVIG) therapy has shown great success in a number of autoimmune and inflammatory conditions and its use continues to increase worldwide. There is growing awareness of significant side effects of high-dose IVIG: however, particularly severe hemolysis in patients that are non-group O. It has been proposed that IVIG-associated hemolysis may be heralded by an existing inflammatory condition. In the work presented herein, we have provided a review of the pathophysiology of inflammation, particularly as it applies in immune-mediated red blood cell hemolysis, and a summary of previous publications that suggest an association between IVIG-mediated hemolysis and a state of existing inflammation. In addition, preliminary results from a prospective study to address the mechanism of IVIG-associated hemolysis are provided. These preliminary data support the idea of an existing inflammatory condition preceding overt hemolysis after high-dose IVIG therapy that: 1) is restricted to non-group O patients, 2) is seen when using IVIG doses of more than 2 g/kg, 3) involves an activated mononuclear phagocyte system, 4) may be presaged by a significant increase in the anti-inflammatory cytokine interleukin-1 receptor agonist, and 5) is independent of secretor status.

Vascular heterogeneity between native rat pancreatic islets is responsible for differences in survival and revascularisation post transplantation

AIMS/HYPOTHESIS

Highly blood-perfused islets have been observed to be the most functional islets in the native pancreas. We hypothesised that differences in vascular support of islets in donor pancreases influence their susceptibility to cellular stress and capacity for vascular engraftment after transplantation.

METHODS

Highly blood-perfused islets in rats were identified by injection of microspheres into the ascending aorta before islet isolation. Cell death was evaluated after in vitro cytokine or hypoxia exposure, and 2 days post transplantation. One month post transplantation, islet engraftment, including vascular density, blood perfusion and oxygen tension (pO2) in the tissue, was evaluated.

RESULTS

Microsphere-containing islets had a similar frequency of cell death during standard culture conditions but increased cell death after exposure to cytokines and hypoxia in comparison with other islets. Two days after transplantation the percentage of apoptotic or necrotic cells was also higher in grafts of such islets and 1 month post transplantation these grafts were composed of substantially more connective tissue. Grafts of highly blood-perfused islets in the native pancreas regained a higher vascular density, blood perfusion and pO2 in comparison with grafts of other islets.

CONCLUSIONS/INTERPRETATION

Native islets that are highly blood-perfused regained this feature after transplantation, indicating a superior capacity for revascularisation and post-transplant function. However, the same group of islets was more vulnerable to different kinds of cellular stress, which limited their early survival post transplantation. Preferential death of these most active islets may contribute to the high number of islets needed to provide cure with islet transplantation.

Fermented soy permeate reduces cytokine level and oxidative stress in streptozotocin-induced diabetic rats

Oxidative stress and inflammation are involved in the development of type 1 diabetes and its complications. Because two compounds found in soy, that is, isoflavones and alpha-galactooligosaccharides, have been shown to exert antioxidant and anti-inflammatory effects, this study aimed to assess the effects of a dietary supplement containing these two active compounds, the fermented soy permeate (FSP). We hypothesized that FSP would be able to reduce in vivo oxidative stress and inflammation in streptozotocin (STZ)-induced type 1 diabetic rats. Thirty male Wistar rats were divided into the control placebo, diabetic placebo, and diabetic FSP-supplemented groups. They received daily, by oral gavage, water (placebo groups) or diluted FSP (0.1 g/day; FSP-supplemented group). After 3 weeks, glycemic regulation (glycemia and fructosamine level); the plasma level of carboxymethyllysine (CML), a marker of systemic oxidative stress in diabetes; and the plasma levels of inflammatory markers (CRP, IL-1β, IL-6, and uric acid) were evaluated. Markers of oxidative damage (isoprostanes and GSH/GSSG), antioxidant enzymatic activity (SOD and GPX), and Mn-SOD content were determined in skeletal muscle (gastrocnemius). Diabetic placebo rats exhibited higher CML levels, lower SOD and GPX activities, and decreased Mn-SOD contents. FSP supplementation in diabetic animals normalized the CML and antioxidant enzymatic activity levels and tended to increase Mn-SOD expression. The markers of inflammation whose levels were increased in the diabetic placebo group were markedly decreased by FSP (IL-1β: -75%, IL-6: -46%, and uric acid: -17%), except for CRP. Our results demonstrate that FSP exhibited antioxidant and anti-inflammatory properties in vivo in STZ-induced diabetic rats.

Advances in the cellular immunological pathogenesis of type 1 diabetes

Type 1 diabetes is an autoimmune disease caused by the immune-mediated destruction of insulin-producing pancreatic β cells. In recent years, the incidence of type 1 diabetes continues to increase. It is supposed that genetic, environmental and immune factors participate in the damage of pancreatic β cells. Both the immune regulation and the immune response are involved in the pathogenesis of type 1 diabetes, in which cellular immunity plays a significant role. For the infiltration of CD4(+) and CD8(+) T lymphocyte, B lymphocytes, natural killer cells, dendritic cells and other immune cells take part in the damage of pancreatic β cells, which ultimately lead to type 1 diabetes. This review outlines the cellular immunological mechanism of type 1 diabetes, with a particular emphasis to T lymphocyte and natural killer cells, and provides the effective immune therapy in T1D, which is approached at three stages. However, future studies will be directed at searching for an effective, safe and long-lasting strategy to enhance the regulation of a diabetogenic immune system with limited toxicity and without global immunosuppression.