Clearance of amyloid-ß protein deposits in transgenic mice following focal cerebral ischemia.

BACKGROUND/AIMS: There is increased amyloid-ß protein precursor (AßPP) expression and amyloid-ß protein (Aß) production in the brain shortly following cerebral ischemic stroke in rodent models. It has been postulated that this may seed amyloid deposition in the brain. On the other hand, it remains unclear how cerebral ischemia affects preexisting Aß deposits in the brain. Here we determine the consequences of focal ischemic stroke on existing Aß pathology in Tg-SwDI transgenic mice. METHODS: At 12 months of age, Tg-SwDI mice were subjected to photo-induced focal cerebral ischemia in one hemisphere. One, 7, or 21 days after lesioning, the amount of deposited Aß in the ischemic and control hemispheres was measured using ELISA. Image analysis was used to visualize deposited Aß and the presence of microglia/macrophages. RESULTS: After 7 days, and further after 21 days, there was a dramatic reduction in the amount of deposited Aß and increased presence of microglia/macrophages in the ischemic hemisphere of the mice. CONCLUSIONS: Focal cerebral ischemia leads to clearance of deposited Aß in Tg-SwDI mice starting at 7 days with almost complete removal in the ischemic area by 21 days. The delayed clearance of Aß following focal cerebral ischemia may involve the infiltration of activated neuroinflammatory cells.

Early-onset subicular microvascular amyloid and neuroinflammation correlate with behavioral deficits in vasculotropic mutant amyloid beta-protein precursor transgenic mice.

Cerebral microvascular amyloid beta protein (Abeta) deposition and associated neuroinflammation are increasingly recognized as an important component leading to cognitive impairment in Alzheimer's disease and related cerebral amyloid angiopathy (CAA) disorders. Transgenic mice expressing the vasculotropic Dutch/Iowa (E693Q/D694N) mutant human Abeta precursor protein in brain (Tg-SwDI) accumulate abundant cerebral microvascular fibrillar amyloid deposits exhibiting robust neuroinflammation. In the present study, we sought to determine if the unique amyloid pathology of Tg-SwDI mice was associated with deficits in behavioral performance. Behavioral performance tests that assessed a variety of psychological functions, including overall activity, motor ability, balance and strength, anxiety, impulsivity, and learning were conducted on homozygous Tg-SwDI mice and similarly aged wild-type C57Bl/6 mice. Our results indicate that Tg-SwDI mice were impaired in the performance of the Barnes maze learning and memory task at 3, 9, and 12 months of age. While more widespread cerebral microvascular Abeta pathology was evident in older animals, the evaluation of the Abeta pathology in the 3 months old transgenic animals revealed specific accumulation of microvascular amyloid and markedly elevated numbers of reactive astrocytes and activated microglia restricted to the subiculum. These findings indicate that early-onset accumulation of subicular microvascular amyloid and accompanying neuroinflammation correlates with impaired performance in the learning and memory task in Tg-SwDI mice.

NO synthase 2 (NOS2) deletion promotes multiple pathologies in a mouse model of Alzheimer's disease.

Alzheimer's disease is characterized by two primary pathological features: amyloid plaques and neurofibrillary tangles. The interconnection between amyloid and tau aggregates is of intense interest, but mouse models have yet to reveal a direct interrelationship. We now show that NO may be a key factor that connects amyloid and tau pathologies. Genetic removal of NO synthase 2 in mice expressing mutated amyloid precursor protein results in pathological hyperphosphorylation of mouse tau, its redistribution to the somatodendritic compartment in cortical and hippocampal neurons, and aggregate formation. Lack of NO synthase 2 in the amyloid precursor protein Swedish mutant mouse increased insoluble beta-amyloid peptide levels, neuronal degeneration, caspase-3 activation, and tau cleavage, suggesting that NO acts at a junction point between beta-amyloid peptides, caspase activation, and tau aggregation.

Insulin aspart improves meal time glycaemic control in patients with Type 2 diabetes: a randomized, stratified, double-blind and cross-over trial.

AIMS: This randomized, multi-centre, double-blind, stratified, two period, cross-over trial was undertaken to assess the pharmacokinetics and pharmacodynamics of insulin aspart injected immediately before compared with regular human insulin injected 30 min before a Mediterranean-style meal in 37 (23 M, 14 F) patients with Type 2 diabetes. METHODS: Insulin aspart or regular human insulin was given subcutaneously (0.15 U/kg) in random sequence, using a double-dummy technique (at one visit: human regular insulin at t=-30 min and placebo at t=0; at the other visit: placebo at t=-30 min and aspart insulin at t=0). Serum glucose and insulin concentrations (15 points) were measured after each meal for 240 min. RESULTS: Post-prandial glycaemic excursions were 20% lower with insulin aspart (IAsp) compared with regular human insulin (HI) treatment [ratio (Iasp/HI)=0.80, CI=(0.66-0.98), P=0.034]. The maximum serum glucose (SG) concentration was similar for the two treatments (P=NS). The (median) time to maximum SG was 25 min shorter for IAsp compared with HI (P=0.048). Maximum serum insulin concentration was higher after IAsp compared with HI (P=0.023) as well as the area under the 4-h serum insulin curve (P=0.006). Furthermore, the time to maximum serum insulin concentration was 27 min shorter after IAsp (P=0.039), even though IAsp was injected 30 min after HI. No adverse events occurred during the trial. CONCLUSIONS: In patients with Type 2 diabetes a more favourable insulin profile and a better glycaemic control were found with IAsp injected immediately before compared with HI injected 30 min before a Mediterranean-style meal.

Effects of a long-term treatment with raloxifene on insulin sensitivity in postmenopausal women.

AIMS/HYPOTHESIS: Our aim was to investigate the effect of long-term administration of raloxifene, a selective estrogen receptor modulator, on insulin sensitivity, glucose tolerance and plasma lipid concentrations in a group of postmenopausal women. METHODS: A total of 24 women with postmenopausal osteoporosis were consecutively enrolled and randomly assigned to take raloxifene, 60 mg/day for 12 months or placebo. At baseline and after 6 and 12 months, in each subject insulin sensitivity (M-index) was assessed by means of an euglycaemic hyperinsulinaemic clamp. Plasma concentrations of total cholesterol, triglycerides and HDL-cholesterol were also measured and glucose tolerance was evaluated. RESULTS: In the raloxifene-treated group, the M index decreased after 6 and 12 months with respect to the placebo group (-21%, p=0.042 and -23%, p=0.018, respectively). Neither fasting plasma glucose nor glucose tolerance changed in the raloxifene-treated group, compared to the placebo group. Low density lipoprotein cholesterol concentrations decreased at 12 months (-13%, p=0.047). CONCLUSION/INTERPRETATION: A long-term treatment with raloxifene in osteoporotic, otherwise healthy post-menopausal women can reduce insulin sensitivity without affecting glucose tolerance.

Serum anti-p53 autoantibodies in patients with type 1 diabetes.

The presence of antibodies reacting with the p53 tumor suppressor protein has been described in patients with some autoimmune disorders. In this study we looked for serum anti-p53 antibodies in 64 patients with autoimmune type 1 diabetes mellitus within 4 mo of diagnosis. The presence of anti-p53 antibodies was observed in 6/64 (9.4%) subjects with type 1 diabetes, and in 1/44 (2.3%) subjects with other organ-specific autoimmune diseases (18 primary biliary cirrhosis, 10 autoimmune hepatitis, 16 thyroid diseases), but in none of 45 control subjects. No relationship was found between antibodies directed against islet- and non-islet-specific antigens and anti-p53 antibodies. These findings support a possible role for p53 in some autoimmune disorders.

Regulation of the sodium iodide symporter by iodide in FRTL-5 cells.

OBJECTIVE: The acute decrease in iodide organification in the thyroid in response to excess iodide is termed the acute Wolff-Chaikoff effect and normal organification resumes in spite of continued high plasma iodide concentrations (escape from the acute Wolff-Chaikoff effect). We have recently reported that large doses of iodide given to rats chronically decrease the sodium/iodide symporter (NIS) mRNA and protein, suggesting that escape is due to a decrease in NIS and subsequent iodide transport. We have now studied the effect of excess iodide on NIS in FRTL-5 cells to further explore the mechanisms whereby excess iodide decreases NIS. DESIGN: FRTL-5 cells were employed and were incubated in the presence or absence of various concentrations of iodide. NIS mRNA and protein and the turnover of NIS were assessed. METHODS: NIS mRNA was measured by Northern analysis, NIS protein by Western analysis and NIS turnover by pulse-chase labeling experiments. RESULTS: Iodide (10(-) mol/l) had no effect on NIS mRNA in FRTL-5 cells at 24 and 48 h compared with cells cultured in the absence of iodide. However, excess iodide decreased NIS protein by 50% of control values at 24 h and by 70% at 48 h. This effect of iodide was dose dependent. Pulse-chase experiments demonstrated that there was no effect of iodide on new NIS protein synthesis and that the turnover of NIS protein in the presence of iodide was 27% faster than in the absence of added iodide. CONCLUSIONS: Excess iodide does not decrease NIS mRNA in FRTL-5 cells but does decrease NIS protein, suggesting that in this in vitro thyroid cell model iodide modulates NIS, at least in part, at a post-transcriptional level. This iodide-induced decrease in NIS protein appears to be due, at least partially, to an increase in NIS protein turnover.

Escape from the acute Wolff-Chaikoff effect is associated with a decrease in thyroid sodium/iodide symporter messenger ribonucleic acid and protein.

In 1948, Wolff and Chaikoff reported that organic binding of iodide in the thyroid was decreased when plasma iodide levels were elevated (acute Wolff-Chaikoff effect), and that adaptation or escape from the acute effect occurred in approximately 2 days, in the presence of continued high plasma iodide concentrations. We later demonstrated that the escape is attributable to a decrease in iodide transport into the thyroid, lowering the intrathyroidal iodine content below a critical inhibitory threshold and allowing organification of iodide to resume. We have now measured the rat thyroid sodium/iodide symporter (NIS) messenger RNA (mRNA) and protein levels, in response to both chronic and acute iodide excess, in an attempt to determine the mechanism responsible for the decreased iodide transport. Rats were given 0.05% NaI in their drinking water for 1 and 6 days in the chronic experiments, and a single 2000-microg dose of NaI i.p. in the acute experiments. Serum was collected for iodine and hormone measurements, and thyroids were frozen for subsequent measurement of NIS, TSH receptor, thyroid peroxidase (TPO), thyroglobulin, and cyclophilin mRNAs (by Northern blotting) as well as NIS protein (by Western blotting). Serum T4 and T3 concentrations were significantly decreased at 1 day in the chronic experiments and returned to normal at 6 days, and were unchanged in the acute experiments. Serum TSH levels were unchanged in both paradigms. Both NIS mRNA and protein were decreased at 1 and 6 days after chronic iodide ingestion. NIS mRNA was decreased at 6 and 24 h after acute iodide administration, whereas NIS protein was decreased only at 24 h. TPO mRNA was decreased at 6 days of chronic iodide ingestion and 24 h after acute iodide administration. There were no iodide-induced changes in TSH receptor and thyroglobulin mRNAs. These data suggest that iodide administration decreases both NIS mRNA and protein expression, by a mechanism that is likely to be, at least in part, transcriptional. Our findings support the hypothesis that the escape from the acute Wolff-Chaikoff effect is caused by a decrease in NIS, with a resultant decreased iodide transport into the thyroid. The observed decrease in TPO mRNA may contribute to the iodine-induced hypothyroidism that is common in patients with Hashimoto's thyroiditis.

The GM2-1 ganglioside islet autoantigen in insulin-dependent diabetes mellitus is expressed in secretory granules and is not beta-cell specific.

The pancreatic islet monosialo-ganglioside (GM2-1), an autoantigen in insulin-dependent diabetes mellitus (IDDM) recently shown to be the target of autoantibodies associated with diabetes development in relatives of IDDM patients, is islet specific within the pancreas, and its expression is metabolically regulatable. In the present study we sought to establish 1) whether GM2-1 is beta-cell specific, and 2) its intracellular localization. To this end, we analyzed the pattern of ganglioside expression in highly purified beta- and non-beta-cells isolated from rat islets. In addition, ganglioside levels were determined in subcellular fractions of a rat beta-cell line (INS). No qualitative or quantitative difference was found in the pattern of ganglioside expression between beta and non-beta rat islet cells, with GM3, GM2-1, and GD3 gangliosides expressed in both cell populations. Within INS cells, GM2-1 ganglioside was expressed in the fraction containing secretory granules and, to a lesser extent, in plasma membranes; GM3 was expressed in secretory granules, whereas GD3 was found only in plasma membranes. These data indicate that the GM2-1 autoantigen is not beta-cell specific within the islets, in accordance with the observation that this molecule is a target of islet cell autoantibodies that bind to the whole pancreatic islet. Interestingly, this autoantigen is present in secretory granules similarly to other autoantigens in IDDM (insulin, carboxypeptidase H, 38-kDa protein, etc.), suggesting that the autoimmunity to the components of this organelle may be central to the pathogenesis of the disease.

Autoimmunity to the GM2-1 islet ganglioside before and at the onset of type I diabetes.

Recently, the GM2-1 pancreatic islet ganglioside, proposed as a potential autoantigen in type I diabetes autoimmunity, has been biochemically characterized and found to be a novel ganglioside structure. In the present study, we aimed to determine whether an autoimmune response toward this novel islet molecule is 1) present in type I diabetes and is specifically directed against this molecule and not to gangliosides in general and 2) predictive of disease in high-risk subjects. To this end, the following patients have been studied: 1) 24 newly diagnosed type I diabetic subjects, 20 islet cell autoantibody (ICA)-negative first-degree relatives of type I diabetic subjects, and 25 age-matched normal control individuals; and 2) 31 prospectively evaluated ICA+ first-degree relatives of type I diabetic subjects who were followed for up to 10 years, during which 14 of them developed type I diabetes. A direct assay for autoantibodies to GM2-1 and to other pancreatic gangliosides (GM3, GD3, GD1a) was developed using an indirect immunoperoxidase technique performed directly on thin layer chromatography plates. Anti-GM2-1 autoantibodies (all belonging to the IgG class) were expressed in a high percentage of newly diagnosed type I diabetic subjects (71%), while no significant difference was found in the expression of antibodies directed against other pancreatic gangliosides (GM3, GD3, GD1a) among the different groups studied. Anti-GM2-1 autoantibodies were also present in ICA+ relatives (64%) (P < 0.001 vs. control subjects and ICA-relatives): in this group, life table analysis of progression to diabetes showed that anti-GM2-1 autoantibodies were significantly (P < 0.001) associated with disease, occurring in all relatives developing type I diabetes within 5 years and thus identifying a cohort of ICA+ subjects with markedly increased diabetes risk.

Interferon-alpha therapy may induce insulin autoantibody development in patients with chronic viral hepatitis.

Development of type 1 insulin-dependent diabetes mellitus has been recently reported in patients who underwent interferon-alpha (IFN-alpha) therapy because of chronic viral hepatitis. Furthermore IFN-alpha seems to be involved in the immunological events that lead to beta-cell destruction and development of type 1 diabetes. To evaluate whether IFN-alpha treatment could elicit an autoimmune response against beta-cell antigens, we determined the occurrence of islet cell antibodies and insulin autoantibodies in the sera of 60 patients with HCV- or HBV-related chronic hepatitis who had been treated with IFN-alpha for 6 or 12 months. The presence of antibodies against thyroglobulin, thyroid microsomal antigen, gastric parietal cells, and non-organ-specific antigens was also investigated. Insulin autoantibody positivity was observed in 2/60 (3.3%), 8/60 (13.3%), and 4/30 (13.3%) patients, before IFN-alpha treatment, and after 6 months and 12 months of therapy, respectively. None of the studied patients developed islet cell antibodies or type 1 diabetes. Before IFN-alpha therapy four patients showed thyroid autoantibodies and four others developed antibodies against thyroglobulin and/or thyroid microsomal antigen during the treatment. Coexistence of insulin autoantibodies and thyroid autoantibodies was observed in only two patients. Our results showed that IFN-alpha therapy in patients with chronic viral hepatitis is capable of inducing development of autoantibodies against insulin. This event seems to be not related to other autoimmune disorders.

Beta-cell markers and autoantigen expression by a human insulinoma cell line: similarities to native beta cells.

In the present study we have evaluated the expression of different beta-cell markers, islet molecules and auto-antigens relevant in diabetes autoimmunity by a human insulinoma cell line (CM) in order to define its similarities with native beta cells and to discover whether it could be considered as a model for studies on immunological aspects of Type 1 diabetes. First, the positivity of the CM cell line for known markers of neuroendocrine derivation was determined by means of immunocytochemical analysis using different anti-islet monoclonal antibodies including A2B5 and 3G5 reacting with islet gangliosides, and HISL19 binding to an islet glycoprotein. Secondly, the expression and characteristics of glutamic acid decarboxylase (GAD) and of GM2-1 ganglioside, both known to be islet autoantigens in diabetes autoimmunity and expressed by human native beta cells, were investigated in the CM cell line. The pattern of ganglioside expression in comparison to that of native beta cells was also evaluated. Thirdly, the binding of diabetic sera to CM cells reacting with islet cytoplasmic antigens (ICA) was studied by immunohistochemistry. The results of this study showed that beta cell markers identified by anti-islet monoclonal antibodies A2B5, 3G5 and HISL-19 are expressed by CM cells; similarly, islet molecules such as GAD and GM2-1 ganglioside are present and possess similar characteristics to those found in native beta cells; the pattern of expression of other gangliosides by CM cells is also identical to human pancreatic islets; beta cell autoantigen(s) reacting with antibodies present in islet cell antibodies (ICA) positive diabetic sera identified by ICA binding are also detectable in this insulinoma cell line. We conclude that CM cells show close similarities to native beta cells with respect to the expression of neuro-endocrine markers, relevant beta cell autoantigens in Type 1 diabetes (GAD, GM2-1, ICA antigen), and other gangliosides. Therefore, this insulinoma cell line may be considered as an ideal model for studies aimed at investigating autoimmune phenomena occurring in Type 1 diabetes.

GM2-1 pancreatic islet ganglioside: identification and characterization of a novel islet-specific molecule.

Recent studies have indicated that GM2-1, a pancreatic islet monosialo-ganglioside, is an islet-specific component whose expression is metabolically regulable and represents one of the target antigens of cytoplasmic islet cell antibodies. In the present study we aimed to biochemically characterize this molecule using a panel of biochemical techniques including gas chromatography, thin layer chromatography, enzymatic digestion and mass spectrometry. GM2-1 ganglioside was extracted from human pancreas and purified by thin-layer chromatography. Fatty acids in the ceramide (the hydrophobic portion of the molecule), identified by gas chromatography ranged from C16:1 to C24:1. The oligosaccharide chain was enzymatically digested by the sequential application of various exoglycosidases (neuraminidase followed by beta-galactosidase, followed by beta-hexosaminidase) and characterized by gas chromatography identification of the liberated sugars. The following structure was deducted from enzymatic studies and confirmed by mass spectrometry analysis: N-acetyl neuraminic acid-galactose-galactosamine-galactosamine-glucose-ceramide. This is a novel ganglioside structure, not yet described, which shares characteristics with a neuronal glycolipid autoantigen: the LM1 ganglioside. Both GM2-1 and LM1 have a single sialic acid residue in the terminal position, the same migration position on thin layer chromatography and the same number of carbohydrate moieties. In conclusion, we have characterized a novel islet-specific ganglioside molecule with unusual characteristics, such as the terminal sialic acid and the galactosamine residues, which may facilitate both its antigenicity and its involvement in beta-cell autoimmunity.

Gastric mucosal mast cells in atopic subjects.

Intragastral allergen provocation under endoscopic control (IPEC) allows direct observation of gastric mucosa reactions after contact with inhalant allergens that reach the stomach. We selected patients with proved atopy to Parietaria but without clinical and endoscopic signs of gastric disease, and we tested them with the specific inhalant allergen during IPEC, recording gastric macroscopic reaction and mucosal mast-cell changes in biopsy specimens. All atopic patients showed visible changes in gastric mucosa quantified as IPEC score. Mast-cell numbers detected in atopic patients (135.4 +/- 102.6/mm2 of stromal area) were significantly higher than in nonatopic subjects (59.8 +/- 25.4/mm2; P < 0.03) and were positively correlated to atopic IPEC score (P < 0.01). In addition, 6/12 atopics who had both higher mast-cell counts and IPEC score showed an intraepithelial distribution of gastric mast cells which displayed ultrastructural features of partial degranulation. It is likely that changes observed in our patients with allergy to Parietaria reflect a subclinical activation of mast cells in the gastric mucosa.

High serum levels of soluble CD8 in insulin-dependent diabetes.

In type 1 (insulin-dependent) diabetes mellitus (IDDM) CD8+ T cells represent the majority of lymphocytes which infiltrate the pancreatic islets during beta cell destruction. Soluble CD8 antigen (sCD8) has been shown to correlate with CD8 cell subset activation. In this study we measured by ELISA sCD8 levels in sera from: 33 newly diagnosed IDDM patients; 29 type 1 diabetics with duration of disease more than 1 year; 37 healthy siblings of IDDM patients; 19 healthy controls. Sera from both groups of IDDM patients and from healthy siblings exhibited soluble CD8 mean levels significantly higher than controls (P = 0.0001, P < 0.003, P < 0.03 respectively). Soluble CD8 levels above the normal range (mean +/- 2 s.d. of controls) were found in a percentage of newly diagnosed subjects (54.5%) significantly higher than in subjects with a long-standing duration of disease (6.9%, P < 0.0005) and healthy siblings (16.2%, P < 0.002). Our results suggest that the raised levels of soluble CD8 near to diabetes onset may indicate the activation of CD8+ T cells probably responsible for the autoimmune beta cell destruction.

Rat pancreatic ganglioside expression: differences between a model of autoimmune islet B cell destruction and a normal strain.

Islet cell antibodies (ICA) bind antigens expressed in both human and rat pancreatic islets. Biochemical studies have shown that an ICA-autoantigen has the properties of a monosialo-ganglioside migrating between GM2 and GM1 standards (GM2-1). We therefore aimed to isolate and characterize gangliosides from whole pancreas and isolated islets of bio breeding diabetes-prone (BB-DP), bio breeding diabetes-resistant (BB-DR), and Wistar Furth (WF) rat strains. Gangliosides were characterized by TLC, HPLC, diode array analysis, and ganglioside-specific staining. ICA binding was studied by indirect immunostaining. The GM2-1 fraction was present in BB-DP, BB-DR, and WF rat pancreases (11, 17, and 9.5%, respectively, of total ganglioside content). Substantial differences were found in other fractions: in BB-DP pancreas, in addition to GM2-1, the main fractions were GM3 (49%), GD1a (12%), GT1b (5%), and a ganglioside migrating between GM1 and GD3 standards (23%), while in BB-DR pancreas the above components were 71, 5.5, 2, and 4.5%, respectively; in WF pancreas, the main fractions were GM3, GD3, GD1a, GT1b and a trisialoganglioside (GT*) migrating above the GT1b standard (42.7, 7, 20.2, 13.8, and 6.8, respectively). A different pattern of ganglioside expression was found in isolated islets of BB-DP, BB-DR, and WF rats: the GM2-1 fraction represented, respectively, 29.1, 30.4, and 31.6% of total ganglioside content; GM3 51.1, 66, and 68.4%. A fraction migrating between GM1 and GD3 standards was present only in BB-DP and BB-DR islets (19.8 and 3.6%, respectively). ICA-positive human sera reacted with pancreas of all rat strains studied, with similar end-point titers. In conclusion, (1) the GM2-1 ganglioside, in the same way as a putative target antigen of ICA, is equally expressed in BB-DP, BB-DR, and WF rat pancreata; and (2) the GM1-GD3 is expressed in higher amounts in BB-DP than in BB-DR pancreas and islets and is absent in WF.

Pancreatic islet ganglioside expression in nonobese diabetic mice: comparison with C57BL/10 mice and changes after autoimmune beta-cell destruction.

Recent observations have shown that the presumed target antigen of cytoplasmic islet cell antibodies (ICA) has properties of a monosialo-ganglioside migrating between GM2 and GM1 standards (GM2-1) and that ICA binding is higher in nonobese diabetic (NOD) than in C57BL/10SnJ mouse pancreatic frozen sections. This study aimed to characterize the ganglioside expression in NOD mouse islets in comparison with the control C57BL/10SnJ strain, taking into account possible sex differences, variations with age, and changes after autoimmune beta-cell destruction. Thus, acidic glycolipid composition was analyzed 1) in isolated islets from 11-week-old female and male NOD mice and age-matched female and male C57BL/10SnJ mice, and 2) in whole pancreas of both NOD and control mouse strains at different ages (4, 8, and 18 weeks) and of female NOD mice before and after diabetes onset. The acidic glycolipid GM2-1 is expressed in isolated female NOD islets, male NOD islets, and C57BL/10SnJ mouse islets, but quantitative analysis showed an increased amount of GM2-1 in NOD vs. C57BL/10 islets. GM3 is a ganglioside fraction expressed in female and male NOD mice and not in the C57BL/10 strain, whereas GD3 characterizes the C57BL/10 strain islets. GM2-1 is the sole ganglioside fraction in the whole pancreas to clearly decrease with age in the NOD mouse, and diabetes onset in this strain is associated with a significant decrease in the expression of this component as well as of GM3, whereas other pancreatic ganglioside (GD3, GD1a, and GT1b) levels did not significantly decrease; no age-related ganglioside change was observed in the C57BL/10SnJ mouse. Interestingly, the observed increased ICA binding in NOD islets is paralleled by the increased expression of GM2-1 islet ganglioside, and beta-cell destruction in NOD mice is associated with a significant decrease in the amount of this ganglioside in the pancreas.