Prediction, prevention, and early intervention in insulin-dependent diabetes

Pancreatic Islet Cells Antibodies in Diabetic Patients Submitted to Pancreas Transplantation

Several pieces of evidence suggest an autoimmune etiology of diabetes mellitus type 1. To trace patients who are susceptible to the disease, we utilized islet cells antibodies (ICAs). The aim of this study was to evaluate the presence of ICAs among diabetic patients undergoing simultaneous transplantation of the pancreas and kidney (SPK). Twenty-six diabetic patients received an SPK, 12 of whom were included in this analysis. The indirect immunofluorescence method was utilized for quantitation of ICAs. The types of ICAs were no different following transplantation of the pancreas. The serum levels of pre-existent ICAS in diabetic patients undergoing SPK with immunosuppression were not reduced, and they did not interfere with the function of the implanted pancreas over a period of 60 days.

Maturity-onset diabetes of the young (MODY): a new challenge for pediatric diabetologists

The differential diagnosis of hyperglycemia in childhood and adolescence has to take into consideration early-onset non-insulin-dependent diabetes, defined as maturity onset diabetes of the young (MODY). To date, mutations in genes of five proteins have been shown to cause MODY: glucokinase (MODY2), hepatic nuclear factor-1 alpha (HNF-1 alpha) (MODY3), hepatic nuclear factor-4 alpha (HNF-4 alpha) (MODY1), insulin promoter factor 1 (IPF-1) (MODY4) and hepatic nuclear factor-1 beta (HNF-1 beta) (MODY5), but other MODY genes still await elucidation. Clinical and metabolic heterogeneity of these subtypes of type 2 diabetes need to be defined, as deficiency of each factor has its own phenotype. Pediatric diabetologists should be aware of the increasing importance of MODY as a possible cause of hyperglycemia in children and adolescents. This will allow for the early diagnosis of these metabolic conditions and for the appropriate follow-up and treatment.

Metabolic and immune parameters at clinical onset of insulin-dependent diabetes: a population-based study. IMDIAB Study Group. Immunotherapy Diabetes

The age at diagnosis of insulin-dependent diabetes mellitus (type I DM) varies between childhood and adulthood. The aim of this study was to define the immunologic and metabolic characteristics of the disease according to the age at which it is diagnosed. We evaluated the residual beta-cell function (basal and stimulated C-peptide) and frequency of two major islet cell-related autoantibodies, glutamic acid decarboxylase (GAD) and tyrosine phosphatase-like molecule (IA-2ic), at the onset of type I DM. A population-based study was performed with 235 consecutive cases of recent-onset (<4 weeks) type I DM (ages 5 to 45 years) diagnosed in the Lazio region of central Italy. Five age groups were considered: patients diagnosed between ages 5 and 7 years (n = 10), 7 and 10 years (n = 38), 10 and 17 years (n = 94), 17 and 20 years (n = 17), and 20 and 45 years (n = 76). Patients diagnosed before puberty had significantly reduced C-peptide secretion compared with patients diagnosed at a later age (P < .02). Glycosylated hemoglobin (HbA1c) did not differ at diagnosis between the different age groups. Patients diagnosed at puberty or after required significantly less insulin compared with younger patients (P < .04). GAD antibodies were found in 65% and IA-2ic antibodies in 59% of patients. GAD antibodies tended to be more frequent in patients diagnosed after age 17 compared with younger patients (P = .05), while IA-2ic antibodies were not age-related. These data suggest that (1) the extent of beta-cell damage differs between patients diagnosed before and after puberty, the process being more destructive in children less than 7 years of age, when C-peptide levels are the lowest; and (2) residual beta-cell function at diagnosis is not influenced by the presence or absence of islet cell-related antibodies. These findings have implications for trials in type I DM diagnosis aimed at protecting beta cells from end-stage destruction and in attempts to prevent the disease in susceptible individuals.

Glycolipids as the major autoantigens of cytoplasmatic islet cell antibodies

It has been recently suggested that pancreatic glycolipidic extracts and acidic glycolipid fractions are able to block the binding of ICA to frozen sections of human pancreas. We study the prevalence of blocking effect by the upper-phase from human pancreatic glycolipid extracts (PGE) in thirty-eight sera ICA positive from seventeen IDDM patients and twenty-one first relatives of type 1 diabetics. Total inhibition was found in 82% and 76% insulin dependent diabetes mellitus patients and first relatives of type 1 diabetics respectively. Partial and no inhibition of ICA+ sera was seen in 6%, 12% of type 1 diabetics and 19%, 5% of the first degree relatives of type 1 diabetics respectively. Our study suggests that there is heterogeneity of cytoplasmatic islet cell antibodies and that glycolipids are the major autoantigen of ICA.

Immunotherapy at clinical diagnosis of insulin-dependent diabetes: an approach still worth considering

Immunointervention at the time of clinical diagnosis of insulin-dependent diabetes has been adopted in many centers throughout the world, with the aim of inducing and maintaining clinical remission (for example, reduction of insulin replacement therapy with normalization of metabolic parameters). Several approaches have been considered, ranging from the use of different kinds of immunosuppression to the use of free oxygen radical scavengers. Although the period of latency before the onset of overt hyperglycemia should be regarded as the most favorable time for any sort of immunointervention, adjuvant treatment at diagnosis (in addition to intensive insulin therapy) may offer clinical advantages in the long term. Thus, maintenance of some residual beta-cell function as a result o f such an approach may improve metabolic control and help to prevent the insurgence of late diabetic complications.

Role of infiltrating T cells for impaired glucose metabolism in pancreatic islets isolated from non-obese diabetic mice

Pancreatic islets isolated from non-obese diabetic (NOD) mice, all of which have insulitis, exhibit an impaired glucose metabolism. In order to investigate the role of infiltrating lymphocytes for this altered metabolism, we injected 12- to 13-week-old female NOD mice with monoclonal antibodies directed against either the alpha beta-T cell receptor, CD4+ or CD8+ T cells. Control NOD mice were injected with normal rat IgG or with the vehicle (phosphate buffered saline) alone. Injection of the three different monoclonal antibodies markedly reduced the mononuclear cell infiltration. An intravenous glucose tolerance test showed no differences between the groups. Islet insulin release in response to glucose was similar in all groups. In contrast, islets isolated from the control NOD mice with insulitis showed a high basal (1.7 mmol/l glucose) glucose oxidation rate and a small increase in the glucose oxidation rate in response to a high glucose concentration (16.7 mmol/l glucose). The monoclonal antibodies counteracted the elevated basal glucose oxidation rate of the islets. Parallel studies of stimulated mononuclear cells suggested that the contribution of glucose oxidized by islet-infiltrating lymphocytes could only partially explain the observed alterations in NOD mouse islet metabolism. Culture of islets obtained from NOD mice in the presence of the cytokine interleukin-1 beta induced a similar pattern of glucose metabolism as seen earlier in IgG or phosphate-buffered saline treated control NOD mice. In conclusion, alterations in the glucose oxidation rates seem to be an early sign of disturbance in islets isolated from NOD mice. These early alterations in glucose metabolism can be reversed in vivo by monoclonal antibodies directed against effector lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclosporine in recent onset type I diabetes mellitus. Effects on islet beta cell function. Miami Cyclosporine Diabetes Study Group

To confirm the immunological basis of type I diabetes and to determine if immune intervention alters the course of the disease, we studied the use of cyclosporine in a 1-year randomized, double-masked, placebo-controlled trial in 23 subjects enrolled within 6 weeks of diagnosis. Subjects included 12 males and 11 females, ages 9-38 years (mean, 19.7 +/- 1.8 years). Initial dosage of cyclosporine was 10 mg/kg/day, given as a single daily dose, adjusted on the basis of side effects and trough cyclosporine levels. Glycemic control and insulin dosage were similar in both cyclosporine and placebo groups. The frequency of freedom from insulin usage also was similar in both groups; however, it is not possible to draw conclusions about response rates, because of the very small sample size. Glucose tolerance, as measured by rate of intravenous glucose disposal did not differ between groups. Islet beta cell function was measured by determining C-peptide response to three secretogogues: intravenous glucagon, intravenous glucose, and a mixed formula meal (Sustacal). There were no differences between groups in the C-peptide responses either to intravenous glucagon or intravenous glucose. Moreover, acute insulin response to intravenous glucose was not restored in any subject. On the other hand, in comparison to the placebo group, the cyclosporine group did show an increased meal-stimulated C-peptide response after 3, 6, 9, and 12 months. When measured by regression analysis, the slope defining the rate of decline of beta cell function was significantly slower for the cyclosporine group than the placebo group (p less than 0.05). Thus, as measured in response to a physiological stimulus (meal challenge), cyclosporine preserves islet beta cell function when used in recent onset type I diabetes. Side effects were minimal and reversible upon cessation of immune intervention. The preservation of islet beta cell function by immune intervention is consistent with the hypothesis that type I diabetes has an immune mechanism involved in its pathogenesis.