elastin and Diabetes-Mellitus--Type-1

Vascular complications are associated with the progressive severity of diabetes, resulting in significant morbidity and mortality. This study quantifies functional vascular parameters and macrovascular structure in a rat model of type 1 diabetes. While there was no difference in the systemic arterial elastance (Ea) with 50 days of diabetes, changes were noted in the aorta and femoral artery including increased tunica media extracellular matrix content, decreased width of both the media and individual smooth muscle cell layers, and increased incidence of damaged mitochondria. Extracellular matrix proteins and elastin levels were significantly greater in the aorta of diabetic animals. These differences correlated with diminished matrix metalloprotease activity in the aorta of the diabetic animals. In conclusion, diabetes significantly altered the structure and ultrastructure of the aorta and femoral artery before systemic changes in arterial elastance could be detected.

Topics: Animals; Aorta; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetic Angiopathies; Elastin; Extracellular Matrix; Extracellular Matrix Proteins; Femoral Artery; Male; Matrix Metalloproteinases; Mitochondria, Muscle; Muscle, Smooth, Vascular; Rats; Rats, Sprague-Dawley; Tunica Media; Vascular Resistance

Elastin breakdown products are found in the serum of all human subjects. The presence of these elastin-derived peptides (EDP) and the corresponding antibodies in circulation leads to formation of circulating immune complexes (CIC). The aim of this study was to determine if serum level of free-EDP (unbound in CIC) correlate with the development of microvascular complications in children with Type 1 (insulin-dependent) diabetes mellitus. To this end we used a method for detecting immune complexes (CIF-ELISA) in combination with an ELISA for detection of EDP. The levels of free EDP were studied in sera of 81 diabetic children (mean age 13.46+/-3.51 years, diabetes duration 5.17+/-4.21 years). Forty-two of the children had vascular complications (group 1) and 39 were without vascular complications (group 2). Twenty-one healthy children (mean age 12.6+/-2.47 years) were used as controls. Diabetics showed significantly higher levels of free EDP (68.1+/-25 ng/ml versus 51+/-12.5 ng/ml; p=0.003) compared to the control group. In group 1, free EDP showed significantly higher levels than controls (78.9+/-25.6 ng/ml versus 51+/-12.5 ng/ml; p=0.0001). About 38 of 81 (47%) patients were positive for free EDP (30/42--71% in group 1 and 8/39--21% in group 2). Free EDP levels in all diabetics showed a correlation with insulin dose (r=0.23; p=0.041), and microalbuminuria (r=0.57; p=0.0001). Patients who had vascular pathology showed a correlation of free EDP with microalbuminuria (r=0.41; p=0.0081), retinopathy (r=0.32; p=0.041), insulin dose (r=0.37; p=0.02), HbA1c (r=0.35; p=0.03), systolic blood pressure (r=0.30; p=0.045) and total cholesterol (r=0.36; p=0.02). These findings suggest that elevated levels of free EDP are associated with the development of diabetic vascular complications in children.

Topics: Adolescent; Antigen-Antibody Complex; Child; Complement Inactivator Proteins; Diabetes Mellitus, Type 1; Elastin; Female; Glycoproteins; Humans; Male; Peptides; Plant Proteins

Antibodies to alpha-elastin (elastin breakdown product) and elastin sequences devoid of cross-linked regions (linear elastin) are found in the serum of all human subjects and correlate with their respective serum peptide levels. The aim of this study was to determine if the serum level of antielastin antibodies (AEAbs) differs between type 1 diabetic children and nondiabetic children. Enzyme-linked immunosorbent assay was used to measure the levels of immunoglobulin (Ig)G and IgM AEAbs in the sera of 45 diabetic children (mean age 12.8 +/- 3.2 years, diabetes duration 5.3 +/- 3.6 years). Twenty-two children presented with vascular complications (group 1), whereas 23 displayed no vascular complications (group 2). The controls were 18 healthy children (mean age 11.9 +/- 2.3 years). Diabetic patients showed statistically significant higher levels of IgM alpha-AEAbs (0.82 +/- 0.26 vs 0.61 +/- 0.14, p = .0013) than the control group. In group 1, alpha-AEAbs showed statistically significant higher level than controls: IgG (0.86 +/- 0.42 vs 0.59 +/- 0.12; p = .0109) and IgM (0.88 +/- 0.24 vs 0.61 +/- 0.14; p = .0001). IgM antilinear elastin antibodies (ALEAbs) in group 1 were significantly lower than in controls (0.462 +/- 0.191 vs 0.652 +/- 0.127; p = .0009). IgG alpha-AEAbs showed correlation with microalbuminuria (r = -.26; p = .05) and IgM ALEAbs correlated with microalbuminuria (r = -.32; p = .035). IgG alpha-AEAbs correlated with neuropathy (r = -.32; p = .035). Group 1 patients displayed a correlation between IgG ALEAbs and retinopathy (r = -.48; p = .023) and IgM ALEAbs and microalbuminuria (r = .52; p = .014). Levels of AEAbs and ALEAbs can serve as immunologic markers of the extent of elastin degradation. These markers may provide a tool to study elastin metabolism and a potential clinical role for AEAbs in the pathogenesis and development of vascular complications in diabetic children.

Topics: Adolescent; Autoantibodies; Case-Control Studies; Child; Diabetes Mellitus, Type 1; Elastin; Female; Humans; Immunoglobulin G; Immunoglobulin M; Male

Antibodies to elastin breakdown products are found in the serum of all human subjects and correlate with their respective serum peptide levels. The presence of these antielastin antibodies (AEAbs) and the corresponding antigens in circulation leads to the formation of circulating immune complexes (CICs). The aim of this study was to determine if the serum levels of free AEAbs (not bound in CICs) correlate with the development of vascular complications in diabetic children. To this end, we used a method for detecting immune complexes (complement inhibition factor [CIF]-enzyme-linked immunosorbent assay [ELISA]) in combination with an ELISA for detection of AEAbs. The levels of free immunoglobulin G (IgG) AEAbs were studied in the sera of 54 diabetic children (mean age 12.3+/-4 years; diabetes duration 5.2+/-3.7 years). Thirty-two of the children had vascular complications (group 1), and 22 were without vascular complications (group 2). Twenty healthy children (mean age 13.6+/-4.2 years) were used as controls. The diabetics showed statistically significant higher levels of free AEAbs (0.490 E492+/-0.244 E492 vs 0.307 E492+/-0.081 E492; p = .02) compared with the control group. In group 1, free AEAbs showed statistically significant higher levels than controls (0.523+/-0.269 vs 0.307+/-0.081; p = .016). Eighteen of 54 (33%) patients were positive for free AEAbs (13 of 32 [41%] in group 1 and 5 of 22 [22%] in group 2). Free AEAb levels in all diabetics showed a correlation with systolic blood pressure (r = .44; p = .01), diastolic blood pressure (r = .46; p = .009), total cholesterol (r = .33; p = .05), triglycerides (r= .38; p = .03), high-density lipoprotein (r= -.46; p = .009), serum fructose (r= .43; p = .001), and microalbuminuria (r= .41; p = .002). Patients who had vascular pathology showed a correlation of free AEAbs with microalbuminuria (r= .434; p= .026), serum fructose (r= .63; p = .0004), hemoglobin A1c (r= .392; p = .043), and triglycerides (r= .456; p = .025). These findings suggest that elevated levels of free IgG AEAbs are associated with the development of diabetic vascular complications in children.

Topics: Adolescent; Autoantibodies; Case-Control Studies; Child; Diabetes Mellitus, Type 1; Diabetic Angiopathies; Elastin; Female; Humans; Immunoglobulin G; Male

The purpose of the study was to measure advanced glycated end products (AGE) of elastin in human serum. In the present study, we adapted an ELISA technique for the determination of AGE-elastin-derived peptides (AGE-EDP) in human sera of healthy and diabetic subjects. This test makes use of human aortic elastin hydrolyzed by a chemical procedure (alpha-elastin) and AGE-Hemocyanin. Polyclonal sera from rabbit against AGE-Hemocyanin and from sheep against alpha-elastin were obtained and their specificity was tested via direct and competitive ELISA. Sera of 60 Type 1 (insulin-dependent) diabetic children and 28 healthy subjects were tested. The patients with vascular complications showed significant higher levels of age, diabetes duration, systolic blood pressure (SBP), diastolic blood pressure (DBP), dose, EDP and AGE-EDP than those without vascular complications. AGE-EDP concentrations of all diabetics correlated with triglycerides (r=0.19; p=0.04). The correlation was found between AGE-EDP and DBP in the subgroup of patients with microalbuminuria+retinopathy (r=0.94; p=0.0006). The subgroup of patients with microalbuminuria (n=19) showed correlation with age (r=0.24; p=0.008), AGE-EDP (r=0.65; p=0.0001), EDP (r=0.51; p=0.0001) and SBP (r=0.33; p=0.0003). Further studies are necessary to elucidate the relationship between the serum level of AGE-elastin degradation products and diabetic vascular complications. The measurement of non-invasive markers of elastin synthesis and degradation may be useful in monitoring development and therapeutic intervention in diabetic vascular complications.

Topics: Adolescent; Blood Pressure; Child; Diabetes Mellitus, Type 1; Elastin; Enzyme-Linked Immunosorbent Assay; Epitopes; Female; Glycation End Products, Advanced; Humans; Immunoglobulin G; Male; Peptides; Triglycerides

Levels of elastin-derived peptides (EDP) were determined by enzyme-linked immunosorbent assay (ELISA) in sera of 28 children with Type 1 (insulin-dependent) diabetes mellitus (mean age 11.6+/-2.8 years, diabetes duration 5.1+/-2.5 years). None of the children had clinical or laboratory evidence of vascular complications. The children were followed over a period of 6 years, and 24 healthy children of similar age and sex served as a control group. During the investigative period, 10 diabetic patients had increased EDP levels, with 9 having been diabetic for more than 5 years and 1 patient less than 5 years. Seven of these patients developed diabetic microvascular complications. In this group, EDP were independently associated with age (r=.39, P=.047), retinopathy (r=.48, P=.034), and antibodies to advanced glycation endproducts (AGE) (r=.52, P=.018). The data of this pilot study are not strong enough to appear that EDP are a useful predictor of subsequent development of microvascular complications. This may be due to the small number of subjects, short duration of the study, manner in which EDP or the endpoints were measured, or frequency of which EDP measurements were made. Further prospective and longer studies of larger populations are needed to identify the role of EDP as an early marker for the development of diabetic microvascular complications.

Topics: Adolescent; Child; Diabetes Mellitus, Type 1; Diabetic Angiopathies; Elastin; Female; Humans; Longitudinal Studies; Male

An important factor in the development of vascular wall alterations is degradation of the elastic fiber major protein-elastin. Elastin peptides derived from this degradation are present in the circulating blood and they are a stimulus for increased production of anti-elastin antibodies (AEAb). The aim of the present study was to examine the possible association between serum elastin AEAb and the development of diabetic vascular complications. Levels of AEAb (IgG, IgM and IgA) were determined by ELISA in sera of 28 children with Type 1 (insulin-dependent) diabetes mellitus (mean age 11.6+/-2.8 years, diabetes duration 5.1+/-2.5 years). None of the children had clinical or laboratory evidence of vascular complications. The children were followed over a period of 7 years, and 24 healthy children of similar age and sex served as a control group. During the study, four diabetics developed retinopathy, six microalbuminuria and two both retinopathy and microalbuminuria. Anti-elastin IgG showed correlation with diabetes duration (r=.48, P=.0007), HbA1c (r=.28, P=.05), triglycerides (r=.28, P=.05) and antibodies to advanced glycation endproducts (AGE) (r=.41, P=.005). Anti-elastin IgM correlated with HbA1c (r=.26, P=.038) and IgA with retinopathy (r=.32, P=.017). Our results suggest an association between the level of anti-elastin IgA antibodies and the development of diabetic retinopathy.

Topics: Adolescent; Antibodies; Child; Diabetes Mellitus, Type 1; Diabetic Retinopathy; Elastin; Female; Glycated Hemoglobin; Humans; Immunoglobulin A; Immunoglobulin M; Male

The aim of this study was to develop an immunoenzyme method for the determination of anti-AGE antibodies in human serum. Human aortic elastin glycated in vitro (AGE-elastin) was used as an antigen, expressing AGE-epitopes, common to all glycated proteins. Polyclonal serum from guinea-pig against AGE-Hemocyanin was obtained according to Nakayama et al. [(1989) Biochem Biophys Res Commun 162: 740-45] and its specificity was tested via direct and competitive ELISA. Sera of 20 type 1 diabetic patients and 20 healthy subjects were tested using the method described. Seventeen patients had elevated levels of competing factors that may be anti-AGE antibodies, compared with the healthy group. The method could be used for investigation of different clinical groups of type 1 diabetic patients. Such a study would help in understanding the pathogenic role of autoantibodies against advanced glycation end products of proteins for the development of long-term diabetic complications.

Topics: Animals; Antibodies; Antibody Specificity; Autoantibodies; Diabetes Mellitus, Type 1; Elastin; Enzyme-Linked Immunosorbent Assay; Epitopes; Glycation End Products, Advanced; Guinea Pigs; Hemocyanins; Humans; Reference Values

Previous studies have shown that biomechanical analysis of aorta from diabetic subjects reveals a marked increase in stiffness compared to aorta from age-matched control subjects. In the present paper we have proposed that this increased stiffness can be attributed to glycation-induced inter-molecular cross-links based on a direct analysis of the two known glycation cross-links, the fluorescent pentosidine and the non-fluorescent NFC-1. There was a significant difference in the increase in concentration of both cross-links with increasing age for both the intima (p < 0.0025) and the media (p < 0.0005) from the diabetic compared to the control subjects, but no correlation with the mature enzymic cross-link hy droxylysyl-pyridinoline. Finally, we have obtained a significant correlation of stiffness with both glycation cross-links (NFC-1, r = 0.86; p < 0.005 and pentosidine r = 0.75, p < 0.05), but the concentration of NFC-1 is about 50 times greater than that of pentosidine, indicating that it is the major glycation cross-link responsible for the stiffening of the aorta.

Topics: Adult; Aged; Aging; Amino Acids; Aorta, Thoracic; Arginine; Collagen; Cross-Linking Reagents; Diabetes Mellitus, Type 1; Diabetic Angiopathies; Elastin; Glycation End Products, Advanced; Humans; Lysine; Middle Aged; Time Factors