i(3)so3-galactosylceramide and Diabetes-Mellitus--Type-2

Mammalian tissues express beta-isoforms of glycosphingolipids and, among these, sulfatide (sulphated galactosylceramide) is present in the beta cells, and it is here that the short fatty acid chain (C16) isoform is predominately found. In vitro studies have shown that sulfatide preserves insulin crystals and facilitates insulin monomerisation under certain biochemical conditions. It also activates beta cell potassium channels and moderates insulin secretion. Anti-sulfatide antibodies are seen in type 1 diabetes, and immunological presentation of glycosphingolipids by the non-classical CD1 molecules has recently been reported. It is via this mechanism that alpha-galactosylceramide and sulfatide are able to influence the innate immune system and inhibit autoimmunity, possibly through regulatory natural killer T cells. Administration of sulfatide substantially reduces the incidence of diabetes in non-obese diabetic mice and prevents antigen-induced experimental autoimmune encephalomyelitis in wild-type mice. Sulfatide has specific anti-inflammatory properties, increasing the number of CD3+CD25+ regulatory T cells and reducing production of several cytokines, including TNF-alpha. Patients with type 2 diabetes have low serum concentrations of sulfatide, and some animal models of type 2 diabetes have low pancreatic expression of C16:0 sulfatide; administration of this increases insulin secretion and improves first-phase insulin response in Zucker fatty rats. Glycosphingolipids in general, and sulfatide in particular, appear relevant to both type 1 and type 2 diabetes.

Topics: Animals; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Humans; Insulin-Secreting Cells; Sulfoglycosphingolipids

Cytokine-induced apoptosis is recognised as a major cause of the decline in β-cell mass that ultimately leads to type 1 diabetes mellitus. Interleukin-1β, interferon-γ and tumour necrosis factor-α in conjunction initiate a series of events that lead to β-cell apoptosis; important among these is NO production. The glycosphingolipid sulfatide is present in β-cells in the secretory granules in varying amounts and is secreted together with insulin. We now investigate whether sulfatide is able to protect insulin-producing cells against the pro-apoptotic effect of interleukin-1β, interferon-γ and tumour necrosis factor-α.. INS-1E cells and genuine rat islets were incubated for 24 h exposed to interleukin-1β, interferon-γ and tumour necrosis factor-α with or without sulfatide. The production of NO was monitored and the number of apoptotic cells was determined using terminal deoxynucleotidyl transferase-mediated dUTP Nick-End labelling and caspase-3/7 activity assays. In addition, the amount of iNOS mRNA was determined using real-time quantitative polymerase chain reaction.. Cytokine-induced apoptosis was reduced to 27% of cytokine-treated controls with 30 µmol/L sulfatide treatment (p < 0.01). Likewise, sulfatide in concentrations of 3-30 µmol/L decreased NO production in a dose-dependent manner to 19-40% of cytokine-treated controls (overall p = 0.0007). The level of iNOS mRNA after cytokine exposure was reduced to 55% of cytokine-treated controls with 30 µmol/L of sulfatide.. In the present study, we report the ability of sulfatide to significantly reduce apoptosis, cellular leakage and NO production in insulin-producing cells. Data suggest this is not due to induction of β-cell rest. Our findings indicate a possible implication for sulfatide in the pathogenesis of diabetes.

Topics: Animals; Apoptosis; Cells, Cultured; Chemokine CCL2; Cytokines; Diabetes Mellitus, Type 2; Glucose; Insulin-Secreting Cells; Interferon-gamma; Interleukin-1beta; Male; Nitric Oxide; Nitric Oxide Synthase Type II; Rats; Rats, Inbred Lew; RNA, Messenger; Sulfoglycosphingolipids; Tumor Necrosis Factor-alpha

The glycosphingolipid beta-galactosylceramide-3-O-sulfate (sulfatide) is present in the secretory granules of the insulin producing beta-cells and may act as a molecular chaperone of insulin. The final step in sulfatide synthesis is performed by cerebroside sulfotransferase (CST) (EC 2.8.2.11). The aim of this study was to investigate whether two single nucleotide polymorphisms (SNP), rs2267161 located in an exon or rs42929 located in an intron, in the gene encoding CST are linked to type 2 diabetes (T2D).. As a population survey, 265 male and female patients suffering from T2D and 291 gender matched controls were examined.. A higher proportion of T2D patients were heterozygous at SNP rs2267161 with both T (methionine) and C (valine) alleles present (49.8% versus 41.3%, P = .04). The calculated odd risk for T2D was 1.47 (1.01-2.15, P = .047). Among female controls, the homozygous CC individuals displayed lower insulin resistance measured by HOMA-IR (P = .05) than the C/T or TT persons; this was particularly prevalent in individuals who exercise (P = .03).. Heterozygosity at SNP rs2267161 in the gene encoding the CST enzyme confers increased risk of T2D. Females with the CC allele showed lower insulin resistance.

Topics: Adult; Aged; Blood Glucose; Body Mass Index; Diabetes Mellitus, Type 2; Exercise; Female; Gene Frequency; Genetic Predisposition to Disease; Glucose Tolerance Test; Homeostasis; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Polymorphism, Single Nucleotide; Sulfoglycosphingolipids; Sulfotransferases; Surveys and Questionnaires; Sweden

The glycosphingolipid sulfatide (sulfated galactosyl-ceramide) increases exocytosis of beta-cell secretory granules, activates K(ATP)-channels and is thereby able to influence insulin secretion through its presence in the islets. A closely related compound, sulfated lactosylceramide (sulf-lac-cer), is present in the islets during fetal and neonatal life when, as in Type 2 diabetes, insulin is secreted autonomically without the usual first phase response to glucose. The aim was to examine whether serum concentrations of these glycolipids are associated with Type 2 diabetes.. A case-control study, comprising 286 women and 283 men, was designed using a population-based sample of patients with Type 2 diabetes and a population survey.. Low serum concentrations of sulfatide were associated with Type 2 diabetes, independent of traditional risk factors for diabetes in a sex-specific analysis: odds ratio (OR) 2.1 (95% confidence interval 1.1, 3.9) in men, and 2.3 (1.2, 4.3) in women, comparing the lowest and the highest tertiles. Type 2 diabetes was also associated with detectable amounts of sulf-lac-cer in serum: OR 1.7 (0.9, 3.4) in men, and 7.6 (3.8, 15.2) in women. After adjustment for confounding from other diabetes risk factors, these associations remained basically unchanged. The connections between sulfatide and Type 2 diabetes, and sulf-lac-cer and Type 2 diabetes were independent of each other. Insulin resistance (HOMA-IR) was negatively correlated with sulfatide concentration and positively correlated with sulf-lac-cer (both P < 0.0001, independently).. We report a new, robust and highly significant independent association between Type 2 diabetes and serum concentrations of sulfatide in both sexes, and sulf-lac-cer in females. The associations were also independent of other known diabetes risk factors.

Topics: Antigens, CD; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Galactosylceramides; Humans; Insulin Resistance; Lactosylceramides; Male; Middle Aged; Population Surveillance; Risk Factors; Sex Distribution; Sulfoglycosphingolipids; Sweden

Sulfatide (3'-sulfogalactosyl-ceramide) is a glycosphingolipid mainly located in the nervous system, but has also been found in the islets of Langerhans. Previous studies have suggested that sulfatide is involved in insulin processing and secretion. In this study, sulfatide expression and metabolism in pancreas and isolated islets of the type II diabetes models, ob/ob- and db/db mouse, was investigated using TLC-ELISA, metabolic labelling and electron microscopy. As in non-diabetic Lewis rat and human pancreas, sulfatide was located in secretory granules of the beta cells. However, the type II diabetic animal models and their background strains had an altered sulfatide expression, involving the lack of the C16:0 sulfatide fatty acid isoform, compared to non-diabetic Lewis rat, BALB/c mouse and human pancreatic tissue, in which the two dominating pancreatic sulfatide isoforms C16:0 and C24:0 are expressed. Correspondingly, in isolated ob/ob islets, sulfatide synthesis excluded the production of C16:0 sulfatide. Insulin administration to ob/ob mouse, which lowers beta cell activity, resulted in significantly increased sulfatide expression in pancreas (p=0.0003), but still no expression of the C16:0 sulfatide isoform. In vitro, the C16:0 sulfatide was shown to be the isomer involved in the preservation of insulin crystals. Thus, it is hypothesized that the selection of sulfatide isomers in pancreas might be a genetic factor contributing to disease development in type II diabetic animal models.

Topics: Animals; Brefeldin A; Chloroquine; Chromatography, Thin Layer; Diabetes Mellitus, Type 2; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Fatty Acids; Fumonisins; Galactosylceramides; Humans; Islets of Langerhans; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Obese; Microscopy, Electron; Protein Isoforms; Protein Synthesis Inhibitors; Rats; Rats, Inbred Lew; Spectrometry, Mass, Electrospray Ionization; Sulfoglycosphingolipids

In sera from newly diagnosed insulin-dependent diabetes mellitus patients (IDDM type 1) autoantibodies occur against different antigen determinants often shared with neural tissues. The role of these autoantibodies in the disease process is not yet clarified but they can be used as a diagnostic tool in the detection of IDDM patients.. We have analysed the occurrence of sulfatide autoantibodies in serum from patients with type 1 diabetes (n = 20), individuals with pre-type 1 diabetes (n = 6), patients with type 2 diabetes (n = 32) and controls (n = 43). The method used for the determination of the autoantibodies was a newly developed microtitre-ELISA assay utilizing a complex of sulfatide-albumin as the ligand.. The new assay procedure for serum sulfatide autoantibodies showed good reproducibility. The total (day-to-day) imprecision based on analyses of three different serum samples with positive titres varied between 11 and 14% during an assay period of 6 months. None of the controls (0/43) had positive titres of sulfatide antibodies. Of the patients with type 1 diabetes, 85% displayed positive titres of anti-sulfatide antibodies while none of the type 2 patients did so. All individuals with pre-type 1 diabetes had positive titres of sulfatide antibodies.. We conclude that sulfatide autoantibodies in serum can be reproducibly assayed by the newly developed microtitre-ELISA procedure. Elevated titres of sulfatide autoantibodies are a constant finding in newly diagnosed type 1 patients.

Topics: Adolescent; Adult; Autoantibodies; Child; Child, Preschool; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Prediabetic State; Sulfoglycosphingolipids

We investigated the presence of antisulfatide and antiphospholipid antibodies and the relationship between these antibodies and the results of quantitative tests of nerve function in NIDDM patients with diabetic neuropathy.. Antisulfatide and antiphospholipid antibodies were measured in serum samples obtained from 68 NIDDM patients with diabetic neuropathy by an enzyme-linked immunosorbent assay (ELISA). Each patient was classified into one of three groups based on the combined neuropathy score (determined by the symptom score, the results of autonomic nerve function tests, and the vibration perception test), as follows: mild (n = 26), moderate (n = 22), and severe (n = 20). Nerve conduction studies were performed in a subgroup of 37 patients.. The antisulfatide antibody was detected in 1 (4%) of 26 patients in the mild group, 4 (18%) of 22 patients in the moderate group, and 8 (40%) of 20 patients in the severe group (P < 0.01 vs. mild group). The antiphospholipid antibody was detected in none of the patients in the mild group, 8 (36%) of 22 patients in the moderate group (P < 0.001 vs. mild group), and 6 (30%) of 20 patients in the severe group (P < 0.01 vs. mild group). The threshold amplitude, determined by the vibration perception test, was significantly higher in antibody-positive patients than in antibody-negative patients: antisulfatide antibody, 55.9 +/- 46.8 microns (n = 13) vs. 22.9 +/- 13.7 microns (n = 55), P < 0.001; antiphospholipid antibody, 47.2 +/- 32.5 microns (n = 14) vs. 24.5 +/- 23.2 microns (n = 54), P < 0.01. The conduction velocity of the sural nerve was slower in the antisulfatide antibody-positive group (37.9 +/- 11.1 m/s, n = 12) than in the antisulfatide antibody-negative group (45.2 +/- 6.0 m/s, n = 19) (P < 0.05).. These results suggest that autoimmune nerve destruction may be involved in diabetic neuropathy in NIDDM patients.

Topics: Aged; Antibodies, Antiphospholipid; Autoantibodies; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Neural Conduction; Phospholipids; Sulfoglycosphingolipids