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J Nerup

Publications and source records attributed to J Nerup.

At least 181 records · Page 10Linked to original sources
PubMed1987

Ultrastructural studies of time-course and cellular specificity of interleukin-1 mediated islet cytotoxicity.

Previous electron-microscopic studies of isolated islets of Langerhans exposed to the monokine interleukin-1 for 7 days have indicated that interleukin-1 is cytotoxic to all islet cells. To study the time-course and possible cellular specificity of interleukin-1 cytotoxicity to islets exposed to interleukin-1 for short time periods, isolated rat or human islets were incubated with or without 25 U/ml highly purified human interleukin-1 for 24 h. Samples of rat islets were taken after 5 min, 30 min, 1, 2, 4, 6, 8, 10, 12, 16, 20 and 24 h and samples of human islets after 5 min, 30 min and 24 h of incubation and examined by electron microscopy in a blinded fashion. Already after 30 min, accumulation of opaque intracytoplasmic bodies without apparent surrounding membranes, and autophagic vacuoles were seen in about 20% of the beta cells examined in rat islets exposed to interleukin-1. After 16 h of incubation with interleukin-1, more than 80% of rat beta cells showed signs of degeneration. Beta cell specific changes similar to those observed in rat islets exposed to IL-1 for 30 min were seen in human islets exposed to IL-1 for 24 h. The described changes were not observed in alpha cells in interleukin-1-treated rat or human islets, or in alpha and beta cells in control islets. Passing interleukin-1 over columns containing Sepharose-coupled anti-interleukin-1 antibody completely removed the beta cell cytotoxic action on rat islets.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Declining incidence of persistent proteinuria in type I (insulin-dependent) diabetic patients in Denmark.

The decreasing relative mortality among type I (insulin-dependent) diabetic patients during the last 50 years might be related to the incidence of clinical diabetic nephropathy. We therefore followed 2890 type I diabetic patients (1607 males and 1283 females) diagnosed between 1933 and 1972 and before the age of 31, from admission to death, emigration, or January 1, 1984. All patients had been admitted to the Steno Memorial Hospital. Information on development of proteinuria was obtained in 2658 patients (92%). Five hundred twenty-five patients developed proteinuria due to diabetes and 49 developed nondiabetic proteinuria. When comparing patients diagnosed between 1933 and 1942 with those diagnosed between 1953 and 1962, the incidence of proteinuria decreased by 30% (P less than .03). This might explain the decrease of relative mortality in type I diabetic patients. The incidence decreased with increasing age at onset but was always highest in males. Insulin dose (U/kg) and diabetes duration at admission did not influence the incidence of proteinuria. The incidence peaked after 15-17 yr of diabetes duration independent of sex, age at diagnosis, or calendar year of diagnosis. However, the majority of patients did not develop proteinuria during 40 yr of diabetes. This suggests individual renal susceptibility to the deleterious effect of hyperglycemia.

Denmark↗
PubMed1987

Islet cytotoxicity of interleukin 1. Influence of culture conditions and islet donor characteristics.

We recently demonstrated that the macrophage product interleukin 1 (IL-1) is cytotoxic to isolated pancreatic islets and hypothesized that IL-1 is responsible for beta-cell destruction in insulin-dependent diabetes mellitus (IDDM). We studied whether the variation in IDDM preponderance with age, sex, and genetic background in vivo is reflected in different susceptibility to IL-1 toxicity of islets in vitro. In addition, we studied the effect of preculture conditions that support endocrine islet cell function and decrease nonendocrine passenger-cell survival on the susceptibility of beta-cells to IL-1 because it is unknown whether IL-1 acts directly on beta-cells or via passenger cells. No differences in susceptibility to various doses of IL-1-containing mononuclear cell supernatants were found between islets isolated from newborn or adult rats, male or female rats, or rats of four inbred strains, indicating that age, sex, and genetic background do not influence the susceptibility of the beta-cell to IL-1. Preculture of islets for 1-7 days in normal atmosphere and preculture of islet clusters in 95% O2 to delete passenger cells did not affect IL-1-mediated cytotoxicity, suggesting that IL-1 acts directly on beta-cells. Increasing the glucose concentration (22 mM) in the culture medium, which is known to protect beta-cells against alloxan toxicity, reduced IL-1 toxicity. Five or 25% normal human serum as well as 5% normal rat serum, but not equivalent concentrations of human serum albumin, inhibited IL-1 toxicity, indicating the presence of IL-1 inhibitors, IL-1 antagonists, or beta-cell-protecting factors in normal serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1987

Detection of islet cell autoantibodies in newly diagnosed diabetic patients using insulin-producing Syrian hamster cells.

An insulin-producing cell line, Clone-16, of hamster origin, was characterized for islet hormone production and for reactivity with islet cell surface (ICSA) and islet cell cytoplasmic (ICA) antibodies in sera from children with newly diagnosed insulin-dependent (Type 1) diabetes mellitus (IDDM). The Clone-16 cells have a doubling time of about 50-60 hr. The cells produced 63 +/- 3 ng (mean +/- SD) immunoreactive insulin and 9.4 +/- 0.3 ng immunoreactive glucagon per day per 10(6) cells, while somatostatin (SRIF) and pancreatic polypeptide (PP) were undetectable. The reactivity with autoantibodies in IDDM sera was assessed by indirect immunofluorescence or 125I-protein A binding assay on intact cells to detect islet cell surface antibodies (ICSA) or on frozen sections of cell pellets to detect islet cell cytoplasmic antibodies (ICCA) by indirect immunofluorescence. Although the proportion of the ICSA-positive Clone-16 cells compared favorably with rat islet cells (r = 0.81; p less than 0.01), we found 5/10 IDDM sera to be positive on rat islet cells but 8/10 on the Clone-16 cells. There was also a good correlation in the 125I-protein A binding assay between mouse islet cells and Clone-16 cells (r = 0.91; p less than 0.01). Frozen sections of Clone-16 cells showed a cytoplasmic immunofluorescence in 8/10 of the IDDM sera and this reaction parallelled the results obtained in the standard indirect immunofluorescence assay with a frozen section of human blood group O pancreas. We conclude that the insulin- and glucagon-producing Clone-16 cells are a useful cell line for detecting islet cell autoantibodies.

Adolescent↗
PubMed1986

Cytotoxicity of human pI 7 interleukin-1 for pancreatic islets of Langerhans.

Activated mononuclear cells appear to be important effector cells in autoimmune beta cell destruction leading to insulin-dependent (type 1) diabetes mellitus. Conditioned medium from activated mononuclear cells (from human blood) is cytotoxic to isolated rat and human islets of Langerhans. This cytotoxic activity was eliminated from crude cytokine preparations by adsorption with immobilized, purified antibody to interleukin-1 (IL-1). The islet-inhibitory activity and the IL-1 activity (determined by its comitogenic effect on thymocytes) were recovered by acid wash. Purified natural IL-1 and recombinant IL-1 derived from the predominant pI 7 form of human IL-1, consistently inhibited the insulin response. The pI 6 and pI 5 forms of natural IL-1 were ineffective. Natural and recombinant IL-1 exhibited similar dose responses in their islet-inhibitory effect and their thymocyte-stimulatory activity. Concentrations of IL-1 that inhibited islet activity were in the picomolar range. Hence, monocyte-derived pI 7 IL-1 may contribute to islet cell damage and therefore to the development of insulin-dependent diabetes mellitus.

Animals↗
PubMed1986

Diabetes mellitus, atherosclerosis, and the 5' flanking polymorphism of the human insulin gene.

On the 5' side of the human insulin gene is a highly polymorphic locus containing 2 major size classes of DNA restriction fragments which segregate in families as stable genetic elements. Fragments with an average size of about 600 base-pairs (bp) (the 'L-allele') seem to be a weak genetic marker for type 1 (insulin-dependent) diabetes mellitus, whereas fragments of an average size of about 2500 bp (the 'U-allele') have hitherto been associated with type 2 (non-insulin-dependent) diabetes mellitus and diabetic hypertriglyceridaemia. Recent evidence does not confirm the association between the U-allele and type 2 diabetes. Our own studies suggest that the U-allele is a fairly strong marker for the development of atherosclerosis with a relative risk for U-carriers of 3.36. The U-allele has not been associated with conventional cardiovascular risk factors such as body weight, blood pressure, or levels of blood glucose, triglycerides or lipoproteins. The putative functions of the polymorphic region in the aetiology of type 1 diabetes and atherosclerosis, and the relation of this region to other genetic markers for these disorders are not known.

Alleles↗
PubMed1986

Affinity-purified human interleukin I is cytotoxic to isolated islets of Langerhans.

Addition of highly purified human Interleukin-1 to the culture medium of isolated rat islets of Langerhans for 6 days led to 88% inhibition of glucose-induced insulin-release, reduction of islet contents of insulin and glucagon to 31% and 8% respectively, and disintegration of the islets. These effects were dose-dependent and reproducible when using three different Interleukin-1 preparations. Highly purified human Interleukin-2, Lymphotoxin, Leucocyte Migration Inhibitory Factor and Macrophage Migration Inhibitory Factor were ineffective. These findings suggest that Interleukin-1 may play an important role in the molecular mechanisms underlying autoimmune B-cell destruction leading to Type 1 (insulin-dependent) diabetes mellitus.

Animals↗
PubMed1986

Mechanisms of pancreatic islet cell destruction. Dose-dependent cytotoxic effect of soluble blood mononuclear cell mediators on isolated islets of Langerhans.

Supernatants of peripheral blood mononuclear cells from healthy human donors stimulated with recall antigen (purified protein derivative of tuberculin) or lectin (phytohaemagglutinin) markedly inhibited the insulin release from isolated human and rat islets of Langerhans, and decreased rat islet contents of insulin and glucagon in a dose-dependent manner. A maximal effect on islet function was obtained with supernatant concentrations down to 5%. Supernatants of mononuclear cells stimulated with tuberculin were more potent than supernatants produced by lectin stimulation. Culture medium reconstituted with tuberculin or phytohaemagglutinin did not impair islet function. Electron microscopy demonstrated that supernatants were cytotoxic to islet cells. The cytotoxic mononuclear cell mediator(s) was non-dialysable, sensitive to heating to 56 degrees C, labile even when stored at -70 degrees C, but stable when lyophilised.

Animals↗
PubMed1986

HLA associations in insulin-dependent diabetes: search for heterogeneity in different groups of patients from a homogeneous population.

A total of 317 unrelated Danish patients with insulin-dependent diabetes mellitus (IDDM) have been HLA-DR typed and the antigen and phenotype frequencies compared with those in 1177 unrelated Danish controls. The strong positive associations with DR3 and 4 and the strong negative one with DR2 were confirmed, and the remaining antigens showed a hierarchy from weakly positive to strongly negative associations: DRw9, w8, 1, 5, w6, 7. The study population included various special groups of patients selected in order to study heterogeneity: very early (less than 5 years) and very late (greater than 40 years) onset IDDM, pregnancy-induced IDDM, IDDM nephropathy, and long-term (greater than 40 years) survivors without complications. When comparing these groups, the following minor differences were seen: the DR3,4 phenotype is significantly (p = .02) more frequent in IDDM with onset before age 20 (35%) than in other cases (24%), and in familial IDDM (48%) than in other cases (28%); the frequency of the DR4 antigen was significantly (p = .008) more frequent in long-term survivors (86%) than in other patients (69%), while it was significantly (p = .02) less frequent in IDDM nephropathy (63%) than in long-term survivors. However, apart from the age-at-onset heterogeneity, which was suspected a priori, these differences may be due to chance, and the main conclusion of this study is that the HLA-DR associations in IDDM are indeed extraordinarily homogeneous irrespective of the clinical characteristics at onset and course of the disease.

Age Factors↗
PubMed1986

Islet cell and other organ-specific autoantibodies in healthy first-degree relatives to insulin-dependent.

The presence of organ-specific autoantibodies including islet cell surface, cytoplasmic and cytotoxic as well as thyroid-gastric antibodies were determined in healthy, non-diabetic, first-degree relatives to 30 insulin-dependent diabetic (IDDM) children. Thirty healthy families without family-history of diabetes mellitus served as controls. The prevalence of organ-specific autoantibodies among the healthy members in the diabetic families was increased compared to the control families (p less than 0.005). Islet cell cytoplasmic antibodies were only detected in diabetes families, since 23% (7/30) of the probands and 7% (2/31) of the siblings were positive and all others negative. Organ-specific autoantibodies were associated with HLA DR3 only in the diabetes families (p less than 0.025) while autoantibody positive members in the control families were associated with HLA B7 (p less than 0.01). This study suggests that childhood IDDM occurs in families with an increased prevalence of organ-specific autoantibodies.

Adolescent↗
PubMed1986

Low concentrations of interleukin-1 stimulate and high concentrations inhibit insulin release from isolated rat islets of Langerhans.

Isolated rat islets were incubated either with crude, affinity-purified or recombinant human interleukin-1 for 1 to 6 days. A significant (20-60%) increase of insulin release was observed at low concentrations of all three interleukin-1-containing preparations. In contrast, higher concentrations dose-dependently inhibited the insulin release. The increased insulin secretion occurred at concentrations below those necessary to augment the mitogen response to phytohaemagglutinin of murine thymocytes in vitro. These doses (0.05-0.5 U/ml) correspond to 0.2-2 ng of recombinant interleukin-1 per ml, equal to approximately 0.01-0.1 pmol/ml. In doses of 0.6-1.8 U/ml affinity-purified interleukin-1 significantly increased the islet insulin content per ng of DNA, indicating a stimulation of insulin-biosynthesis. The data support the concept that low concentrations of interleukin-1 may play a role in priming the physiological secretion of insulin.

Animals↗
PubMed1986

Direct effects of cyclosporin A on human pancreatic beta-cells.

Cyclosporin A (CyA) may induce clinical remission in newly diagnosed insulin-dependent diabetes mellitus patients. Recently, however, adverse effects of high doses of CyA on rodent islets have been reported in vivo and in vitro. The possible direct effects of CyA on the human endocrine pancreas were therefore evaluated. Islets isolated from eight necrokidney donors were cultured in the presence of a therapeutically relevant dose of CyA, i.e., 100 ng/ml. During a 5-day culture period the release of insulin was reduced by 36% (range 7-61%), whereas the islets' content of insulin was increased by 59% (range 3-268%). The glucagon content was not affected. Cyclosporin G inhibited the insulin release, whereas dihydrocyclosporin D had no consistent effects. Glucose-stimulated insulin release from perifused islets was markedly depressed in CyA-treated islets. This effect was not fully reversed 48 h after removal of the drug. We concluded that CyA has a direct inhibitory effect on insulin release from human pancreatic islets with a concomitant increase in the residual insulin content. If applicable to the in vivo condition, CyA may therefore, in addition to its immunosuppressive effect, have direct effects on the endocrine pancreas, which may be relevant for clinical application of the drug.

Adolescent↗
PubMed1985

Disappearance and reappearance of islet cell cytoplasmic antibodies in cyclosporin-treated insulin-dependent diabetics.

In 68 newly diagnosed patients with insulin-dependent diabetes mellitus (IDDM) whose treatment included cyclosporin (CyA) the prevalence and mean titre of islet cell cytoplasmic antibodies (ICA) fell faster than they did in the 56 who received only insulin. However, in the CyA-treated patients the prevalence or titre of ICA at diagnosis did not correlate with beta-cell function as measured by glucagon-stimulated C-peptide levels; improvement and recovery of beta-cell function after 30 days of CyA therapy occurred despite the continued presence of ICA; and CyA-induced remission of IDDM (ie, glucagon stimulated plasma C-peptide levels greater than 0.6 pmol/ml) was not predicted by nor coincident with disappearance of ICA. Therefore, although CyA therapy was associated with a higher than expected frequency of remission and faster disappearance of ICA, the two observations were not temporally and may not be causally related. ICA should not be used to identify the target population for or to predict response to immunosuppressive therapy. The contribution of ICA to the pathogenesis of beta-cell destruction in IDDM needs serious re-examination.

Adolescent↗