Diet with a low n-6/n-3 essential fatty acid ratio when started immediately after the onset of overt diabetes prolongs survival of type 1 diabetes model NOD mice

Metabolic and Metabolomic Insights Regarding the Omega-3 PUFAs Intake in Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is currently considered an autoimmune disease characterized by the destruction of pancreatic β-cells, insulin deficiency, and dysglycemia. Dietary factors, including omega-3 polyunsaturated fatty acids (ω-3 PUFAs), were reported to influence T1DM. Therefore, a better understanding of the potential role of ω-3 PUFAs in the development and progression of T1DM will help to improve the clinical management of the disease. In this review, we explored the current understanding of molecular mechanisms and signaling pathways induced by ω-3 PUFAs and the beneficial effects of ω-3 PUFAs intake in the prevention and treatment of T1DM, as well as the underlying possible metabolomic (lipidomics) changes.

Prolonged Honeymoon Period in a Thai Patient with Adult-Onset Type 1 Diabetes Mellitus

Objective

To describe a usual case of adult-onset T1DM with prolonged honeymoon period for more than 5 years.

Methods

Repeated mixed meal stimulation tests for a period of 6–12 months together with monitoring pancreatic autoantibodies and laboratory data were followed following the onset of diagnosis.

Results

We report a 24-year-old Thai patient with T1DM with sustained remission without antidiabetic medication for more than 5 years while maintaining low-carbohydrate intake and regular exercise. Repeated mixed meal stimulation tests for a period of 6–12 months revealed preserved beta-cell functions. Interestingly, repeated pancreatic autoantibodies at 5 years after diagnosis still showed positive anti-GAD, anti-IA2, and anti-ZnT8.

Conclusion

Restored beta-cell function with complete insulin withdrawal in new-onset T1DM has been reported in very few cases with some common factors as in our patient (low-carbohydrate intake with regular exercise). Delaying autoimmune activity by reducing metabolic load in newly diagnosed T1DM might play a role in maintaining the honeymoon period and could lead to an innovative therapeutic option in new-onset T1DM.

Macrophage inflammatory state in Type 1 diabetes: triggered by NLRP3/iNOS pathway and attenuated by docosahexaenoic acid

Type 1 diabetes mellitus (T1D) is a chronic autoimmune disease characterized by insulin-producing pancreatic β-cell destruction and hyperglycemia. While monocytes and NOD-like receptor family-pyrin domain containing 3 (NLRP3) are associated with T1D onset and development, the specific receptors and factors involved in NLRP3 inflammasome activation remain unknown. Herein, we evaluated the inflammatory state of resident peritoneal macrophages (PMs) from genetically modified non-obese diabetic (NOD), NLRP3-KO, wild-type (WT) mice and in peripheral blood mononuclear cells (PBMCs) from human T1D patients. We also assessed the effect of docosahexaenoic acid (DHA) on the inflammatory status. Macrophages from STZ-induced T1D mice exhibited increased inflammatory cytokine/chemokine levels, nitric oxide (NO) secretion, NLRP3 and iNOS protein levels, and augmented glycolytic activity compared to control animals. In PMs from NOD and STZ-induced T1D mice, DHA reduced NO production and attenuated the inflammatory state. Furthermore, iNOS and IL-1β protein expression levels and NO production were lower in the PMs from diabetic NLRP3-KO mice than from WT mice. We also observed increased IL-1β secretion in PBMCs from T1D patients and immortalized murine macrophages treated with advanced glycation end products and palmitic acid. The present study demonstrated that the resident PMs are in a proinflammatory state characterized by increased NLRP3/iNOS pathway-mediated NO production, up-regulated proinflammatory cytokine/chemokine receptor expression and altered glycolytic activity. Notably, ex vivo treatment with DHA reverted the diabetes-induced changes and attenuated the macrophage inflammatory state. It is plausible that DHA supplementation could be employed as adjuvant therapy for treating individuals with T1D.

Development and optimization of spray-dried functional oil microcapsules: Oxidation stability and release kinetics

This study aimed to optimize the microencapsulation method for a functional oil using high amylose corn starch (HACS) and assessed its structure and antioxidant capacity. The results showed that the optimal microencapsulation condition is achieved by using 28.5% of functional oil, 15.75% of HACS, and 57.86% of proportion of monoglyceride in emulsifier with 94.86% microencapsulation efficiency. Scanning electron microscopy and particle size measurement showed that the functional oil microcapsules were uniform size, smooth surface, spherical shape, and without cracks in the wall of the capsules. In vitro oil release of microencapsulates results showed that microencapsulated functional oil containing HACS has a better sustained release effect. The microcapsules containing HACS exhibited a lower lipid oxidation rate during storage. In conclusion, microencapsulation of HACS as wall material improved the stability of functional oil and this formulation of microcapsules was satisfactorily applied in powdered food for diabetic patients.

PUFAs supplementation affects the renal expression of pannexin 1 and connexins in diabetic kidney of rats

In diabetic nephropathy (DN), intercellular communication is disrupted. Connexins (Cx) have a crucial role in that process. Dietary ratios and supplementation with polyunsaturated fatty acids (PUFAs) can alleviate diabetic complications and cause alterations in Cx levels. Although pannexins (Panx) share similarities with members of the Cx family, their function in diabetic nephropathy has still not been fully determined. We studied the influence of PUFA supplementation on the immunoexpression of Px1 and Cx family members in diabetic kidneys of rats. Four groups of rats in experimental DM1 model were supplemented with different dietary n-6/n-3 ratios; ≈7 in control (C) and diabetic groups (STZ), ≈ 60 in the STZ + N6 group and ≈ 1 (containing 16% EPA and 19% DHA) in the STZ + N3 group. Immunoexpression of Cx40, Cx43, Cx45 and Panx1 was evaluated in the renal tissue of diabetic rats using immunohistochemistry. Diabetes significantly decreased the protein expression of Cx40 and Cx43 and increased Panx1 protein expression in the renal cortex (p < 0.05-p < 0.01). There was a significant impact of diet on Cx and Panx1 immunoexpression. Dietary supplementation with a high n-6/n-3 ratio downregulated the protein expression of Cx45 and Panx1 in diabetic rats (p < 0.05-p < 0.01), while Cx43 immunoexpression was increased in diabetic rats fed with high and low n-6/n-3 ratios (p < 0.01-p < 0.001). Hyperglycaemic conditions in DN interfere with cell-to-cell communication and disturb the connection between cells and their immediate environment due to variations in connexin and pannexin immunoexpression. These variations can be regulated by PUFA dietary intake, suggesting their beneficial effect and possible therapeutic option.

The Role of Vitamin D and Omega-3 PUFAs in Islet Transplantation

Recurrence of autoimmunity and allograft rejection represent major challenges that impact the success of islet transplantation. Despite the remarkable improvements achieved in immunosuppression strategies after the publication of the Edmonton protocol, long-term data of intra-hepatic islet transplantation show a gradual decline in beta-cell function. Therefore, there is a growing interest in the investigation of novel, safe and effective anti-inflammatory and immunomodulatory strategies able to promote long-term islet graft survival and notable improvements in clinical outcomes of islet transplant recipients. Vitamin D has been shown to exert anti-inflammatory and immunomodulatory effects. Pre-clinical studies investigating the use of vitamin D and its analogs (alone or in combination with immunosuppressive agents and/or other anti-inflammatory agents, such as omega-3 polyunsaturated fatty acids) showed beneficial results in terms of islet graft survival and prevention of recurrence of autoimmunity/allograft rejection in animal models of syngeneic and allogeneic islet transplantation. Moreover, epidemiologic studies demonstrated that vitamin D deficiency is highly prevalent after solid organ transplantation (e.g., heart, liver or kidney transplantation). However, studies that critically assess the prevalence of vitamin D deficiency among islet transplant recipients have yet to be conducted. In addition, prospective studies aimed to address the safety and efficacy of vitamin D supplementation as an adjuvant immunomodulatory strategy in islet transplant recipients are lacking and are therefore awaited in the future.

Therapeutic Potential of ω-3 Polyunsaturated Fatty Acids in Human Autoimmune Diseases

The recognition of ω-3 polyunsaturated acids (PUFAs) as essential fatty acids to normal growth and health was realized more than 80 years ago. However, the awareness of the long-term nutritional intake of ω-3 PUFAs in lowering the risk of a variety of chronic human diseases has grown exponentially only since the 1980s (1, 2). Despite the overwhelming epidemiological evidence, many attempts of using fish-oil supplementation to intervene human diseases have generated conflicting and often ambiguous outcomes; null or weak supporting conclusions were sometimes derived in the subsequent META analysis. Different dosages, as well as the sources of fish-oil, may have contributed to the conflicting outcomes of intervention carried out at different clinics. However, over the past decade, mounting evidence generated from genetic mouse models and clinical studies has shed new light on the functions and the underlying mechanisms of ω-3 PUFAs and their metabolites in the prevention and treatment of rheumatoid arthritis, systemic lupus erythematosus (SLE), multiple sclerosis, and type 1 diabetes. In this review, we have summarized the current understanding of the effects as well as the underlying mechanisms of ω-3 PUFAs on autoimmune diseases.

Influence of Vitamin D on Islet Autoimmunity and Beta-Cell Function in Type 1 Diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease leading to immune-mediated destruction of pancreatic beta cells, resulting in the need for insulin therapy. The incidence of T1D is increasing worldwide, thus prompting researchers to investigate novel immunomodulatory strategies to halt autoimmunity and modify disease progression. T1D is considered as a multifactorial disease, in which genetic predisposition and environmental factors interact to promote the triggering of autoimmune responses against beta cells. Over the last decades, it has become clear that vitamin D exerts anti-inflammatory and immunomodulatory effects, apart from its well-established role in the regulation of calcium homeostasis and bone metabolism. Importantly, the global incidence of vitamin D deficiency is also dramatically increasing and epidemiologic evidence suggests an involvement of vitamin D deficiency in T1D pathogenesis. Polymorphisms in genes critical for vitamin D metabolism have also been shown to modulate the risk of T1D. Moreover, several studies have investigated the role of vitamin D (in different doses and formulations) as a potential adjuvant immunomodulatory therapy in patients with new-onset and established T1D. This review aims to present the current knowledge on the immunomodulatory effects of vitamin D and summarize the clinical interventional studies investigating its use for prevention or treatment of T1D.

Remission Phase in Paediatric Type 1 Diabetes: New Understanding and Emerging Biomarkers

Type 1 diabetes (T1D) is a metabolic disease of unknown aetiology that results from the autoimmune destruction of the β-cells. Clinical onset with classic hyperglycaemic symptoms occurs much more frequently in children and young adults, when less than 30% of β-cells remain. Exogenous insulin administration is the only treatment for patients. However, due to glucose dysregulation, severe complications develop gradually. Recently, an increase in T1D incidence has been reported worldwide, especially in children. Shortly after diagnosis, T1D patients often experience partial remission called "honeymoon phase," which lasts a few months, with minor requirements of exogenous insulin. In this stage, the remaining β-cells are still able to produce enough insulin to reduce the administration of exogenous insulin. A recovery of immunological tolerance to β-cell autoantigens could explain the regeneration attempt in this remission phase. This mini-review focuses on the remission phase in childhood T1D. Understanding this period and finding those peripheral biomarkers that are signs of immunoregulation or islet regeneration could contribute to the identification of patients with a better glycaemic prognosis and a lower risk of secondary complications. This remission phase could be a good checkpoint for the administration of future immunotherapies.

Targeting dysfunctional beta-cell signaling for the potential treatment of type 1 diabetes mellitus

Since its discovery and purification by Frederick Banting in 1921, exogenous insulin has remained almost the sole therapy for type 1 diabetes mellitus. While insulin alleviates the primary dysfunction of the disease, many other aspects of the pathophysiology of type 1 diabetes mellitus are unaffected. Research aimed towards the discovery of novel type 1 diabetes mellitus therapeutics targeting different cell signaling pathways is gaining momentum. The focus of these efforts has been almost entirely on the impact of immunomodulatory drugs, particularly those that have already received FDA-approval for other autoimmune diseases. However, these drugs can often have severe side effects, while also putting already immunocompromised individuals at an increased risk for other infections. Potential therapeutic targets in the insulin-producing beta-cell have been largely ignored by the type 1 diabetes mellitus field, save the glucagon-like peptide 1 receptor. While there is preliminary evidence to support the clinical exploration of glucagon-like peptide 1 receptor-based drugs as type 1 diabetes mellitus adjuvant therapeutics, there is a vast space for other putative therapeutic targets to be explored. The alpha subunit of the heterotrimeric G_z protein (Gα_z) has been shown to promote beta-cell inflammation, dysfunction, death, and failure to replicate in the context of diabetes in a number of mouse models. Genetic loss of Gα_z or inhibition of the Gα_z signaling pathway through dietary interventions is protective against the development of insulitis and hyperglycemia. The multifaceted effects of Gα_z in regards to beta-cell health in the context of diabetes make it an ideal therapeutic target for further study. It is our belief that a low-risk, effective therapy for type 1 diabetes mellitus will involve a multidimensional approach targeting a number of regulatory systems, not the least of which is the insulin-producing beta-cell. Impact statement The expanding investigation of beta-cell therapeutic targets for the treatment and prevention of type 1 diabetes mellitus is fundamentally relevant and timely. This review summarizes the overall scope of research into novel type 1 diabetes mellitus therapeutics, highlighting weaknesses or caveats in current clinical trials as well as describing potential new targets to pursue. More specifically, signaling proteins that act as modulators of beta-cell function, survival, and replication, as well as immune infiltration may need to be targeted to develop the most efficient pharmaceutical interventions for type 1 diabetes mellitus. One such beta-cell signaling pathway, mediated by the alpha subunit of the heterotrimeric G_z protein (Gα_z), is discussed in more detail. The work described here will be critical in moving the field forward as it emphasizes the central role of the beta-cell in type 1 diabetes mellitus disease pathology.

Small molecules exert anti-apoptotic effect and reduce oxidative stress augmenting insulin secretion in stem cells engineered islets against hypoxia

Transplantation of pancreatic islets is the most reliable treatment for Type 1 diabetes. However cell death mediated by hypoxia is considered as one of the main difficulties hindering success in islet transplantation. The aim of our experiment was to investigate the role of small molecules in survival of Islet like cell aggregates (ICAs) engineered from umbilical cord matrix under oxygen deprived condition (<5% O₂). ICAs were analyzed for cell death via fluoroscein diacetate/propidium iodide (FDA/PI) staining, estimation of Caspase 3 and free radical release in presence and absence of small molecules. The samples were also analyzed for the presence of hypoxia inducible factor 1α (HIF1α) at both transcriptional and translational level. The addition of small molecules showed profound defensive effect on ICAs under hypoxic environment as evidenced by their viability and insulin secretion compared to untreated ICAs. The combinations of Eicosapentaenoic acid (EPA), Docosahexaenoic acid(DHA) and metformin and EPA, DHAandγ amino butyric acid (GABA) acted as anti-apoptotic agents for human ICAs when exposed to 1% O₂ for 48h. The combinations of the small molecules reduced the total reactive oxygen species and malonaldehyde (MDA) levels and enhanced the production of glutathione peroxidise (GPx) enzyme under hypoxic conditions. Finally the increase in HIF1α at both protein and gene level confirmed the defensive effect of the additives in hypoxia. These results suggest that the combination of small molecules maintained the viability and functionality of the ICAs in hypoxia by up-regulating HIF1α expression and down regulating the Caspase 3 activity.

Diet-induced dysbiosis of the intestinal microbiota and the effects on immunity and disease

The gastrointestinal (GI) microbiota is the collection of microbes which reside in the GI tract and represents the largest source of non-self antigens in the human body. The GI tract functions as a major immunological organ as it must maintain tolerance to commensal and dietary antigens while remaining responsive to pathogenic stimuli. If this balance is disrupted, inappropriate inflammatory processes can result, leading to host cell damage and/or autoimmunity. Evidence suggests that the composition of the intestinal microbiota can influence susceptibility to chronic disease of the intestinal tract including ulcerative colitis, Crohn’s disease, celiac disease and irritable bowel syndrome, as well as more systemic diseases such as obesity, type 1 diabetes and type 2 diabetes. Interestingly, a considerable shift in diet has coincided with increased incidence of many of these inflammatory diseases. It was originally believed that the composition of the intestinal microbiota was relatively stable from early childhood; however, recent evidence suggests that diet can cause dysbiosis, an alteration in the composition of the microbiota, which could lead to aberrant immune responses. The role of the microbiota and the potential for diet-induced dysbiosis in inflammatory conditions of the GI tract and systemic diseases will be discussed.

Individual variation in organ histogenesis as a causative factor in the developmental origins of health and disease: unnoticed congenital anomalies?

Morphological studies of congenital anomalies have mainly focused on abnormal shape (i.e. malformation) and thus on disturbed organogenesis. However, in regard to postnatal functions of organs that develop through branching mechanisms, organ size is another important morphological feature. These organs consist of a large number of structural and functional units, such as nephrons in the kidney, and the total number of these units, that is approximately proportional to the organ size, has been shown to vary widely among individuals. Organ-specific cells are differentiated and organized to form structural units and realize organ-specific functions during the histogenetic period (i.e. from mid-gestation to the early postnatal period). The total number of units is attained at the end of histogenesis and determines the total functional capacity, including the functional reserve of the organ, and thus may be related to predispositions to postnatal organ-based diseases, because the functional reserve decreases during the course of life and eventually become short of the minimum requirement of each organ. Therefore, it may be hypothesized that a smaller number of units of organs at the end of histogenesis is one of the predisposing factors for postnatal diseases (i.e. a form of unnoticed but late-manifested congenital anomalies), in this era of extended longevity. However, the mechanisms that control the total number of units in each organ during histogenesis and the possible relationship among the numbers of units in different organs remain unknown. Here, we review our trials based on the above hypothesis in order to (1) mathematically analyze the morphometric data of the different organs in fetuses to elucidate relationship among developing organs, (2) analyze the developing neuro-immuno-endocrine network as a series of mechanisms to systemically correlate the histogenesis of multiple organs, and (3) examine the maternal environment, including dietary fat, as a factor to influence histogenesis and thus the predisposition to type 1 diabetes.

Maternal dietary n-6/n-3 fatty acid ratio affects type 1 diabetes development in the offspring of non-obese diabetic mice

Environment factors, including maternal or infant dietary nutrition have been reported to have an influence on the pathogenesis of type 1 diabetes. In the present study, to investigate the effect of maternal or post-weaning offspring's nutrition, in particular the essential fatty acid ratio (n-6/n-3) on the development of type 1 diabetes, we prepared two kinds of chows with n-6/n-3 ratios of 3.0 (L) and 14.5 (H), and provided them to mothers of non-obese diabetic (NOD) mice during gestation and lactation and to the offspring after weaning. The n-6/n-3 ratios in breast milk and erythrocyte membrane of NOD offspring became nearly the same with that of the maternal diet at 2 weeks after birth. In the L chow-fed offspring from L chow-fed mother (LLL), levels of insulitis were higher than those in the H chow-fed offspring from H chow-fed mother (HHH) at 4 weeks of age, while the levels in the LLL offspring became lower than those in the HHH after 6 weeks. Early insulin autoantibody expressions were found from 2 to 6 weeks in the HHH offspring, but not in the LLL. The LLL offspring exhibited strong suppression of overt diabetes development in regard to the onset and accumulated incidence of diabetes compared to the HHH. The study with combined L and H chows during gestation, lactation in mother and in post-weaning offspring revealed that only the LLH chow significantly suppressed the development of diabetes with similar kinetics to LLL chow, although the other combinations may delay the onset of diabetes. The present findings suggest that n-6/n-3 ratio of the maternal diet during gestation and lactation rather than that of offspring after weaning strongly affects the development of overt diabetes in NOD mice.