Consequences of a family history of type 1 and type 2 diabetes on the phenotype of patients with type 2 diabetes.
(73/1523)
OBJECTIVE: To investigate the impact of a family history of type 1 and type 2 diabetes on the phenotype of patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: In a population-based study, we compared the phenotype in 3 groups of patients with type 2 diabetes. The first group had no family history of diabetes (FH-, n = 148); the second group had a family history of type 2 diabetes only (FH+(TYPE2), n = 1,211); and the third group had a family history of both type 1 and type 2 diabetes (FH+(MIXED), n = 240). Furthermore, we studied the frequency of GAD antibodies (GADabs), HLA-DQB1 risk genotypes, and the presence of coronary heart disease (CHD) according to family history in unrelated patients with type 2 diabetes from 787 families (148 FH-, 546 FH+(TYPE2) and 93 FH+(MIXED)). RESULTS: Patients with no family history of diabetes were older at the onset of the disease, had a better beta-cell function (P = 0.004), and had higher HDL cholesterol concentrations (P = 0.006) than patients with a family history of diabetes. Patients with a family history of only type 2 diabetes had higher BMI and fasting C-peptide concentrations (P = 0.031) but lower frequency of GADab (11 vs. 23%, P = 0.001) and DQB1 risk genotypes (37 vs. 54%, P = 0.003) compared with patients with a family history of both type 1 and type 2 diabetes. In addition, hypertension (P = 0.05) and CHD (P = 0.031) were more common in FH+(TYPE2) than in FH+(MIXED) patients. In patients <60 years old, a family history of type 1 diabetes was associated with a reduced risk of CHD independent of age, hypertension, and HDL cholesterol concentrations. The results were similar when the GADab+ patients were excluded from the analysis. CONCLUSIONS: A family history of both type 1 and type 2 diabetes had a profound influence on the phenotype of patients with type 2 diabetes, which suggests a genetic interaction between type 1 and type 2 diabetes. (+info)
Diabetes in the Old Order Amish: characterization and heritability analysis of the Amish Family Diabetes Study.
(74/1523)
OBJECTIVE: The Old Order Amish (OOA) are a genetically well-defined closed Caucasian founder population. The Amish Family Diabetes Study was initiated to identify susceptibility genes for type 2 diabetes. This article describes the genetic epidemiology of type 2 diabetes and related traits in this unique population. RESEARCH DESIGN AND METHODS: The study cohort comprised Amish probands with diabetes who were diagnosed between 35 and 65 years of age and their extended adult family members. We recruited 953 adults who represented 45 multigenerational families. Phenotypic characterization included anthropometry, blood pressure, diabetes status, lipid profile, and leptin levels. RESULTS: The mean age of study participants was 46 years, and the mean BMI was 26.9 kg/m2. Subjects with type 2 diabetes were older, more obese, and had higher insulin levels. The prevalence of diabetes in the OOA was approximately half that of the Caucasian individuals who participated in the Third National Health and Nutrition Examination Survey (95% CI 0.23-0.84). The prevalence of diabetes in the siblings of the diabetic probands was 26.5% compared with a prevalence of 7.0% in spouses (lambdaS = 3.28, 95% CI 1.58-6.80). The heritability of diabetes-related quantitative traits was substantial (13-70% for obesity-related traits, 10-42% for glucose levels, and 11-24% for insulin levels during the oral glucose tolerance test; P = 0.01 to <0.0001). CONCLUSIONS: Type 2 diabetes in the Amish has similar phenotypic features to that of the overall Caucasian population, although the prevalence in the Amish community is lower than that of the Caucasian population. There is significant familial clustering of type 2 diabetes and related traits. This unique family collection will be an excellent resource for investigating the genetic underpinnings of type 2 diabetes. (+info)
Association of HELLP syndrome with autoimmune antibodies and glucose intolerance.
(75/1523)
OBJECTIVE: HELLP syndrome is a severe form of preeclampsia, characterized by hemolysis (H), elevated liver enzymes (EL), and low platelets (LP), whose pathogenesis is unclear. Autoimmunity is thought to play an important role. After the observation of development of type 1 diabetes in a patient with HELLP syndrome, we assumed a possible disease association based on autoimmune reactions. RESEARCH DESIGN AND METHODS: We examined 70 women with HELLP syndrome for the presence of autoimmune markers and glucose intolerance. Free thyroxine, triiodothyronine, thyroid-stimulating hormone, anti-thyroglobulin antibodies, thyroperoxidase antibodies, thyrotropin receptor antibodies, antinuclear antibodies (ANAs) and anti-DNA, islet cell antibodies, GADA, an oral glucose tolerance test, and HbA1c were determined postpartum. Patients with positive autoimmune markers or glucose intolerance were prospectively followed and repeated testing was performed. There were 60 women with a normal course of pregnancy matched for age, BMI, and number of pregnancies, which served as a control group. RESULTS: From the HELLP patients, 22 (31%) compared with only 6 (10%) control subjects had autoimmune antibodies (P < 0.01). There were 16 HELLP patients (23%) who exhibited only 1 kind of autoantibody (5 ANA, 9 thyroid antibodies, and 2 GADA), whereas in 6 HELLP patients (8.5%) 2 different antibodies were found. In all but 4 patients of the study group, these antibodies disappeared during 3 +/- 1.5 years of follow-up. Glucose intolerance was detected in 22 (31%) of the HELLP patients, 17 of them had impaired glucose tolerance (IGT), and 5 had diabetes, whereas only 4 subjects (6.5%) with IGT at postpartum were found in the control group (P < 0.01). During the follow-up, 2 HELLP patients were still diabetic and another 2 HELLP patients (1 GADA positive) had IGT versus 1 control subject. CONCLUSIONS: Our data give evidence that HELLP syndrome is associated with various autoimmune antibodies and glucose intolerance. Because glucose intolerance and/or autoimmune markers persisted during long-term follow-up in 6 patients with HELLP syndrome versus 1 in the control group, it may become advisable to reexamine patients with HELLP syndrome for detection of diabetes and autoimmune disorders. (+info)
High frequency of persisting or increasing islet-specific autoantibody levels after diagnosis of type 1 diabetes presenting before 40 years of age. The Belgian Diabetes Registry.
(76/1523)
OBJECTIVE: To study the presence and levels of GAD65 antibodies (GADA), IA-2 antibodies (IA-2-A), and islet cell antibodies (ICA) during the first years after clinical onset of type 1 diabetes in relation to age at diagnosis. RESEARCH DESIGN AND METHODS: Type 1 diabetic patients (n = 194) <40 years of age were consecutively recruited at the time of diagnosis by the Belgian Diabetes Registry and followed during the first 4 years of insulin treatment. ICA were determined by indirect immunofluorescence assay and IA-2-A, GADA, and insulin autoantibodies by a radioligand assay. RESULTS: Overall, 94% of initially antibody-positive patients (n = 180) remained positive for at least 1 antibody type 4 years after diagnosis. In the case of diagnosis after 7 years of age, GADA, IA-2-A, and ICA persisted in 91, 88, and 71%, respectively, of the initially antibody-positive patients. Antibody persistence was lower in those diagnosed at <7 years of age, amounting to 60% for GADA, 71% for IA-2-A, and 39% for ICA. In 57% of the initially antibody-positive patients, at least 1 type of autoantibody reached peak values after diagnosis. This occurred more frequently for clinical onset after 7 years of age and more often for GADA (49%) than for IA-2-A (29%) or ICA (19%). Of the patients, 24% that were negative for GADA at onset became GADA-positive during the following 4 years. Among the 7% initially antibody-negative patients, 2 of 14 subjects developed antibodies after clinical onset. CONCLUSIONS: In particular, for diagnosis after 7 years of age, islet cell-specific autoantibodies generally persist for many years after diagnosis. There is also a high frequency of increasing antibody levels and of conversion to antibody positivity in the first 4 years after diagnosis and start of insulin treatment. Thus, determination of antibodies at diagnosis can underestimate the number of cases with autoimmune type 1 diabetes, in particular with assays of lower sensitivity. The divergent temporal patterns of ICA, GADA, and IA-2-A suggest that the ICA test recognizes other antibody specificities besides GADA and IA-2-A and reflects other autoimmune processes; it also indicates that GADA assays have a higher diagnostic sensitivity in the period after clinical onset. (+info)
c-Fos expression in GABAergic, serotonergic, and other neurons of the pontomedullary reticular formation and raphe after paradoxical sleep deprivation and recovery.
(77/1523)
The brainstem contains the neural systems that are necessary for the generation of the state of paradoxical sleep (PS) and accompanying muscle atonia. Important for its initiation are the pontomesencephalic cholinergic neurons that project into the pontomedullary reticular formation and that we have recently shown increase c-Fos expression as a reflection of neural activity in association with PS rebound after deprivation in rats (Maloney et al. , 1999). As a continuation, we examined in the present study c-Fos expression in the pontomedullary reticular and raphe neurons, including importantly GABAergic neurons [immunostained for glutamic acid decarboxylase (GAD)] and serotonergic neurons [immunostained for serotonin (Ser)]. Numbers of single-labeled c-Fos+ neurons were significantly increased with PS rebound only in the pars oralis of the pontine reticular nuclei (PnO), where numbers of GAD+/c-Fos+ neurons were conversely significantly decreased. c-Fos+ neurons were positively correlated with PS, whereas GAD+/c-Fos+ neurons were negatively correlated with PS, suggesting that disinhibition of reticular neurons in the PnO from locally projecting GABAergic neurons may be important in the generation of PS. In contrast, through the caudal pons and medulla, GAD+/c-Fos+ cells were increased with PS rebound, covaried positively with PS and negatively with the electromyogram (EMG). In the raphe pallidus-obscurus, Ser+/c-Fos+ neurons were positively correlated, in a reciprocal manner to GAD+/c-Fos+ cells, with EMG, suggesting that disfacilitation by removal of a serotonergic influence and inhibition by imposition of a GABAergic influence within the lower brainstem and spinal cord may be important in the development of muscle atonia accompanying PS. (+info)
Vestibular signals in the parasolitary nucleus.
(78/1523)
Vestibular primary afferents project to secondary vestibular neurons located in the vestibular complex. Vestibular primary afferents also project to the uvula-nodulus of the cerebellum where they terminate on granule cells. In this report we describe the physiological properties of neurons in a "new" vestibular nucleus, the parasolitary nucleus (Psol). This nucleus consists of 2,300 GABAergic neurons that project onto the ipsilateral inferior olive (beta-nucleus and dorsomedial cell column) as well as the nucleus reticularis gigantocellularis. These olivary neurons are the exclusive source of vestibularly modulated climbing fiber inputs to the cerebellum. We recorded the activity of Psol neurons during natural vestibular stimulation in anesthetized rabbits. The rabbits were placed in a three-axis rate table at the center of a large sphere, permitting vestibular and optokinetic stimulation. We recorded from 74 neurons in the Psol and from 23 neurons in the regions bordering Psol. The activity of 72/74 Psol neurons and 4/23 non-Psol neurons was modulated by vestibular stimulation in either the pitch or roll planes but not the horizontal plane. Psol neurons responded in phase with ipsilateral side-down head position or velocity during sinusoidal stimulation. Approximately 80% of the recorded Psol neurons responded to static roll-tilt. The optimal response planes of evoked vestibular responses were inferred from measurement of null planes. Optimal response planes usually were aligned with the anatomical orientation of one of the two ipsilateral vertical semicircular canals. The frequency dependence of null plane measurements indicated a convergence of vestibular information from otoliths and semicircular canals. None of the recorded neurons evinced optokinetic sensitivity. These results are consistent with the view that Psol neurons provide the vestibular signals to the inferior olive that eventually reached the cerebellum in the form of modulated climbing fiber discharges. These signals provide information about spatial orientation about the longitudinal axis. (+info)
Distributions of synaptic vesicle proteins and GAD65 in deprived and nondeprived ocular dominance columns in layer IV of kitten primary visual cortex are unaffected by monocular deprivation.
(79/1523)
Two days of monocular deprivation (MD) of kittens during a critical period of development is known to produce a loss of visual responses in the primary visual cortex to stimulation of the nondeprived eye, and 7 days of deprivation results in retraction of axon branches and loss of presynaptic sites from deprived-eye geniculocortical arbors. The rapid loss of responsiveness to deprived-eye visual stimulation could be due to a decrease in intracortical excitatory input to deprived-eye ocular dominance columns (ODCs) relative to nondeprived-eye columns. Alternatively, deprived-eye visual responses could be suppressed by an increase in intracortical inhibition in deprived columns relative to nondeprived columns. We tested these hypotheses in critical period kittens by labeling ODCs in layer IV of primary visual cortex with injections of the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L) into lamina A of the lateral geniculate nucleus (LGN). After either 2 or 7 days of MD, densities of intracortical excitatory presynaptic sites within deprived relative to nondeprived ODCs were estimated by measuring synaptic vesicle protein (SVP) immunoreactivity (IR). Because most of the synapses within layer IV of primary visual cortex are excitatory inputs from other cortical neurons, levels of SVP-IR provide an estimate of the amount of intracortical excitatory input. We also measured levels of immunoreactivity of the inhibitory presynaptic terminal marker glutamic acid decarboxylase (GAD)65 in deprived relative to nondeprived ODCs. Monocular deprivation (either 2 or 7 days) had no effect on the distributions of either SVP- or GAD65-IR in deprived and nondeprived columns. Therefore, the rapid loss of deprived-eye visual responsiveness following MD is due neither to a decrease in intracortical excitatory presynaptic sites nor to an increase in intracortical inhibitory presynaptic sites in layer IV of deprived-eye ODCs relative to nondeprived columns. (+info)
Exposure to exogenous insulin promotes IgG1 and the T-helper 2-associated IgG4 responses to insulin but not to other islet autoantigens.
(80/1523)
Insulin immunization in animal models induces T-helper (Th) 2-like antibody subclass responses to insulin and other beta-cell antigens. The aim of this study was to determine whether exposure to insulin in humans resulted in a similar subclass bias of the humoral immune response. Levels of IgG subclass antibodies to insulin (IAs), GAD, and IA-2 were measured before and after treatment with insulin in the following groups of patients: 29 patients with newly diagnosed type 1 diabetes treated with intravenous and/or subcutaneous insulin; 10 newly diagnosed patients randomized to cyclosporin A (CsA) or placebo plus subcutaneous insulin for 12 months; and 14 islet cell antibody-positive relatives receiving either intravenous and subcutaneous insulin prophylaxis or no treatment. At the onset of diabetes, the major subclass distributions of insulin autoantibodies (IAAs) were IgG1 and, to a lesser extent, IgG4. After insulin treatment in the 29 new-onset patients, IAs were initially of the IgG1 subclass. IgG4-IAs appeared later, but at 12 months, they were at higher levels than IgG1-IAs in 11 patients. Responses were higher in children compared with adults and were higher in subjects with IAAs (P < 0.001). Insulin prophylaxis in relatives showed a similar profile, with a decline in levels of IgG1-IAs after cessation of daily subcutaneous insulin. Patients treated with CsA took longer to develop IAs and showed suppressed levels of IgG4-IAs; however, their levels of high-titer IgG1-IAs persistently rebounded after completion of CsA therapy. Despite the presence of IgG4-IAs in most insulin-treated patients and relatives, a shift to IgG4-anti-GAD or IgG4-IA-2 was not found for up to 3 years after the initiation of insulin therapy. While our findings need to be correlated with T-cell cytokine responses, we suggest that the strong IgG4-IA response in insulin-treated patients is consistent with an enhancement of Th2 immunity, but there is no evidence of subsequent spreading of potentially Th2-associated IgG4 responses to other autoantigens. (+info)