B-cell function and blood glucose control in insulin dependent diabetics within the first month of insulin treatment

Summary Seventeen insulin dependent diabetics were studied after two to four weeks of insulin treatment in a situation approximating to their normal daily life. Some endogenous insulin secretion, assessed by plasma C-peptide determinations, was present in all. Plasma C-peptide concentration was positively correlated with the blood glucose concentration and increased after breakfast, lunch and dinner (p<0.01); both peak values and relative increases were lower than those observed in normal subjects (p<0.01). The highest insulin secretory capacity was found in subjects with the least unstable blood glucose concentration (r=0.57, p <0.03), and these patients required the smallest insulin doses (r=0.54, P<0.04). These findings demonstrate the metabolic importance of a preserved B-cell function.     

不同胰岛素抵抗状态的初诊2型糖尿病患者短期胰岛素强化疗效观察

对62例不同胰岛素抵抗状态的初诊2型糖尿病患者进行2周胰岛素强化治疗,结果显示胰岛素强化治疗降糖效果确切,能改善β细胞功能,但有明显胰岛素抵抗的患者治疗效果欠佳。     

Decrease of antibodies to insulin,proinsulin and contaminating hormones after changing treatment from conventional beef to purified pork insulin

Summary The sera of 30 patients who had been treated with conventional beef insulin were tested for binding of insulin and other pancreatic hormones. All showed antibody binding of insulin, 29 binding of proinsulin, 29 binding of pancreatic polypeptide, two binding of glucagon but none of the sera bound vasoactive intestinal peptide or somatostatin. After changing therapy to highly purified pork insulin the binding capacity of sera for insulin and the other hormones was monitored for up to 35 months and a steady fall was found in nearly all cases. In eight of the patients conventional beef insulin treatment was resumed: in one month binding of insulin and of the other hormones increased back to the initial levels. In eighteen subjects who had only received highly purified pork insulin low levels of insulin binding were found with no binding of proinsulin or other hormones. The amounts of proinsulin and contaminating hormones in highly purified pork insulin are so low that they are not immunogenic; conventional beef insulin not only contains immunogenic amounts of proinsulin and the contaminating hormones pancreatic polypeptide and glucagon but also is more immunogenic than purified pork insulin.     

Comparison of liquid phase radiobinding assay and solid phase ELISA for the measurement of insulin antibodies and insulin autoantibodies in serum

Sera containing insulin antibodies from 20 insulin-treated diabetic patients, sera containing insulin autoantibodies from 20 insulin-naive non-diabetic patients, and from 10 normal controls, were tested at 1:20 dilution in three different radioimmunoassays (RIA) and an enzyme linked immunosorbent assay (ELISA), using a highly purified human insulin ligand. The RIA using insulin radiolabelled at multiple sites detected insulin antibodies in 17/20 and insulin autoantibodies in 13/20 sera. The same RIA using A-14-monoiodinated insulin was sensitive to antibodies and autoantibodies in all the sera. The same RIA using sera after insulin extraction detected only 13/20 diabetic sera and 9/20 autoimmune sera as positive, owing to a substantial rise in non-specific binding of the control sera. ELISA was sensitive to insulin antibodies and autoantibodies in every case. When binding curves for ELISA and the most sensitive RIA were compared using serial dilutions of four insulin antibody containing sera and four insulin autoantibody containing sera, antibody titres varied from 1.1 to 3.8 times higher in ELISA, and autoantibody titres from 10.6 to 28.6 times higher in ELISA. These studies indicate that ELISA is more sensitive than RIA to insulin antibodies, and in particular to insulin autoantibodies.     

Controlled study comparing treatment with monocomponent insulin and conventional insulin in patients with lipoatrophy

Summary Twenty-one patients with evident lipoatrophy treated with conventional (Conv.) insulin were either allocated to continuation of treatment with previously used insulin (Conv. group, n=10) or were transferred to Lente? MC (monocomponent) insulin with or without supplementary Actrapid? MC insulin (MC group, n=11). On entry and after 3, 6 and 12 months of follow-up, serum insulin-, pancreatic polypeptide- and proinsulin-binding IgGs were determined by radioimmunoelectrophoresis according to the method of Christiansen. Prior to determination of proinsulin-binding IgG, the insulin-binding IgG was removed by means of sepharose-bound insulin according to the method of Heding. In both groups a slight decrease in the titer of insulinbinding IgG was observed: in the Conv. group from 5.33±0.92 (SEM) to 4.66±1.17 mU/ml after 12 months, and in the MC group from 3.22±0.64 to 2.66±0.46 mU/ml, respectively. Due to the small number of patients with pancreatic polypeptide antibody titers above the detection limit no statistical evaluation was carried out. The level of serum proinsulin-binding IgG decreased in the MC group only (from 9.3±2.2 to 1.9±0.6 ng/ml after 12 months), and even showed a slight increase in the Conv. group (the respective titers were: 14.0±4.6 and 14.9±4.6 ng/ml). In the MC group 10 patients (91%) showed improvement and 7 (64%) complete regression of their lipoatrophy corresponding to 6 (60%) and 2 (20%) in the Conv. group. This finding suggests a possible role of proinsulin-binding antibodies in the pathogenesis of insulin lipoatrophy.     

血清胰岛素免疫检测及相关问题

血清胰岛素检测对糖代谢疾病的研究有着重要的临床参考价值.胰岛素检测技术经历了近50年的衍变历程,大体上能符合临床研究的要求.但由于胰岛素分子免疫原性和生物活性的多元性、检测体系的复杂性和多重因素的干扰性,目前仍缺乏统一的参考标准,给临床和不同实验室进行胰岛素测定值比较带来一定困难.     

Failure of appearance of insulin antibodies in dogs adapted to bovine-porcine insulin

Summary 1. After a slowly increased adaptation to insulin (commercial normal insulin, i.e. a mixture of bovine-porcine insulin) two dogs showed no circulating insulin antibodies, despite daily subcutaneous application of 4 IU/kg body weight for more than 2 years. — 2. The non-appearance of circulating insulin antibodies was confirmed by several experimentsin vitro andin vivo especially by autoradiography — immunoelectrophoresis and determination of IBC before as well as after the removal of insulin from the serum. — 3. The biological activity of unlabelled bovine insulin after I.V. injection was not diminished in the dogs adapted to insulin.

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Fehlen von Insulinantikörpern bei an Binder- und Schweininsulin angepaten Hunden

Zusammenfassung 1. Nach einer langsam ansteigenden Anpassung an Insulin (kommerzielles Alt-Insulin, eine Mischung von Rinder- und Schweineinsulin) zeigten 2 Hunde keine zirkulierenden Insulinantikörper, obwohl 4 IE/kg Körpergewicht über zwei Jahre täglich subcutan injiziert wurden. — 2. Das Fehlen von zirkulierenden Insulinantikörpern wurde durch verschiedene Experimentein vitro undin vivo, insbesondere durch Autoradiographie — Immunelektrophorese und Bestimmung der IBC vor und nach Entfernung des Insulins aus dem Serum bekräftigt. — 3. Die biologische Aktivität unmarkierten Rinderinsulins war nach i.v.-Injektion bei den adaptierten Hunden nicht vermindert.

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Non-apparition d'anticorps antiinsuline chez des chiens adaptés à de l'insuline bovine et porcine

Résumé 1. Après une adaption lentement progressive à l'insuline (insuline normale du commerce, mélange d'insulines de boeuf et de porc), deux chiens n'ont montré aucun anticorps circulant contre l'insuline, malgré l'application quotidienne sous-cutanée de 4 IU/kg durant plus de deux ans. — 2. La non-apparition d'anticorps circulants contre l'insuline a été confirmée par plusieurs expériencesin vitro etin vivo, en particulier par autoradiographie — immunoélectrophorèse et détermination d'IBC aussi bien avant qu'après avoir retiré l'insuline du sérum. — 3. L'activité biologique de l'insuline de boeuf non marquée, après l'injection intra-veineuse, n'a pas diminué chez les chiens adaptés à l'insuline.

     

Persistent insulin secretion,assessed by plasma C-peptide estimation in long-term juvenile diabetics with a low insulin requirement

Summary In order to investigate whether patients with long-standing juvenile diabetes mellitus (onset of diabetes before the age of 30) and a low daily insulin requirement (< 0.50 units/kg body weight) still have functioning B-cells, plasma C-peptide was determined after stimulation (OGTT and glucagon/ tolbutamide) in 64 patients with diabetes of more than 18 years' duration (mean 31 years). Measurable endogenous insulin production was found in 24% of the patients. The prevalence of severe retinopathy was lower in the secretors than in the non-secretor group. There was no difference in insulin antibody concentration between the two groups. Furthermore, the insulin requirement in the secretor group was relatively constant during the course of diabetes. Metabolic control was similar in both groups. It is concluded that a persisting but low activity of endogenous insulin production can be found in many long-term juvenile diabetics with a low insulin requirement, while others without any residual betacell function develop a low insulin requirement for unknown reasons.     

Measurement of free insulin concentrations: the influence of the timing of extraction of insulin antibodies

Summary Plasma insulin concentrations of insulin-treated diabetic patients must be measured after removal of insulin antibodies, usually by precipitation with polyethylene glycol (PEG). Details of the procedure vary between laboratories; commonly, frozen plasma is thawed and incubated at 37 °C to restore a presumed equilibrium between free and antibody bound insulin before extraction. The present study was designed to investigate methodological factors that could affect the measured free insulin concentration. In normal subjects PEG extraction of globulins did not disturb measurement of insulin concentrations, whether carried out after incubation for 2 h at 37 °C, or storage at -20 °C, in either order. Freezing or incubation of PEG extracts of plasma from insulin-treated patients also failed to disturb the measured concentrations of free insulin. When plasma from patients was incubated for 2 h after storage, a marked scatter (51–272%) of measured results occurred when compared to bedside extraction. This problem was not overcome by buffering with HEPES or storage at a lower temperature (-40 °C). Incubation at 0 °C also severely disturbed the apparent concentrations. Incubation of plasma before extraction and freezing also disturbed the measured result, a problem not corrected by maintaining near physiological pH. Total insulin concentrations measured on acid extracts were not disturbed by any of these manoeuvres. The temperature of centrifugation of blood at the time of venepuncture did not influence the result. Furthermore, when insulin concentrations were rising or falling similar percentage changes were seen over a 30-min incubation of plasma before extraction on the day of venepuncture, suggesting that equilibrium between free and bound insulin is maintained in vivo. We suggest that, for accurate estimation of free insulin concentrations in insulin-treated diabetic patients, immediate centrifugation of blood and extraction of insulin antibodies is mandatory.     

Subpopulations of antibodies directed against evolutionarily conserved regions of the insulin molecule in insulin-treated patients

Summary In the present study, we attempted to define possible subpopulations of antibodies which theoretically could be directed against evolutionarily conserved regions of the insulin molecule in sera from insulin-treated diabetic patients using a variety of labelled and unlabelled insulins which differ widely in structure but are very similar in functional properties. Ten high titre human insulin antisera from patients treated with mixed beef-pork insulin were examined. All sera were found to bind ¹²⁵I-pork insulin better than labelled chicken insulin which bound better than labelled fish insulin. Detailed studies were conducted with four of the antisera using the pork and fish tracers. With two of the antisera, a subpopulation of antibody could be detected with ¹²⁵I-fish insulin which had similar affinity for both fish and pork insulin, but reacted much less well with guinea pig insulin and the desoctapeptide derivative of porcine insulin. Based on the known properties of these four insulins, the data provide suggestive evidence consistent with the hypothesis that there are subpopulations of antibodies recognizing regions on the insulin molecule that are well conserved, possibly the region involved in the formation of insulin dimers or receptor binding.     

Insulin antibodies do not influence the absorption rate of subcutaneously injected insulin

The influence of insulin antibodies on absorption rate and plasma free insulin concentrations after subcutaneous injection of insulin, was studied in two groups of insulin-treated diabetic patients, one without insulin antibodies (n = 9) and a second with high plasma concentrations of antibodies (n = 14). Except for antibody concentration there were no differences in clinical variables. During 8 h after the injection of 12 U of iodinated neutral human insulin, residual radioactivity at the injection site, plasma glucose, and free and total insulin were measured. Significant differences in absorption rate of insulin were not found between the groups. Plasma glucose (basal value 16.8 +/- 4.4 SD vs 16.1 +/- 4.2 mmol l-1) and free insulin (basal value 8.3 +/- 1.4 vs 11.4 +/- 2.3 mU l-1, maximum after 90 min 36.9 +/- 19.5 vs 30.5 +/- 18.7 mU l-1) were never significantly different between the groups, nor were areas under the curve for free insulin (191.4 +/- 69.2 vs 170.8 +/- 98.6 mU l-1 h). In the high antibody group a small increase in bound insulin was found.     

继发性磺脲类失效糖尿病患者胰岛素释放及外周胰岛素敏感度的研究

本文应用７５ｇ葡萄糖耐量试验对１８例继发性磺脲类药物治疗失效ＮＩＤＤＭ患者的胰岛素释放及外周胰岛素敏感度进行了测算，结果发现，继发性磺脲类失效ＮＩＤＤＭ患者的胰岛素释放和外周胰岛素敏感度均显著低于磺脲类药物治疗有效的ＮＩＤＤＭ患者及正常对照。提示继发性磺脲类失效ＮＩＤＤＭ患者存在明显的胰岛素分泌功能损害和外周胰岛素抵抗。     

A longitudinal study of insulin antibodies and anti-insulin cytotoxicity in type I diabetes mellitus

Summary Insulin antibodies and T-cell lymphocyte cytotoxic reactivity against insulin and its related peptides were studied longitudinally in 3 groups of patients with type I diabetes mellitus (DM). Group 1 patients were those in whom the diagnosis was made within 1 week of the initiation diagnosis. They were subdivided into those receiving MC porcine (A) or MC bovine (B) insulin. Group 2 patients were those with a duration of DM for 2–6 years who were receiving either MC porcine (A) or MC bovine (B) insulins. Group 3 subjects were those who had been on conventional recrystallized insulin and then switched to MC porcine (A) or MC bovine (B) insulins for 2 weeks before the start of the study. The incidence of cytotoxic reactions and insulin antibodies were approximately 40–50% for group 1 (either 1A or 1B) at the initiation of the study. At 3-month follow up all patients in group 1B developed insulin antibodies (p<0.02) and a significant increase in the frequency of cytotoxic reactions (p<0.01). By contrast there was a decline in the frequency of cytotoxic reactions in group 1A (p<0.01 at 1 year) and the increase in insulin antibodies was non-significant. Group 2B had higher frequency in cytotoxic reactions (p<0.005) and of insulin antibodies (p<0.05) than group 2A. A significant decrease (p<0.01) in cytotoxic reactions was observed at 3 months following the switch of patients from conventional bovine insulin preparations to ‘A’ but not to ‘B’. However in both subgroups insulin antibodies persisted for at least 12 months. Cross-reactivity between antibodies to human, porcine and bovine insulins was evident in all groups. The early cellular and humoral immune phenomena were positively correlated in both group 1A and 1B suggesting their common involvement in the pathogenesis of DM.     

那格列奈-静脉葡萄糖胰岛素释放试验评价2型糖尿病患者胰岛素第一时相分泌功能

目的用那格列奈-静脉葡萄糖胰岛素释放试验（NG—IVGIRT）评价新诊断的2型糖尿病（DM）患者胰岛B细胞第一时相胰岛素分泌的功能。方法8例新诊断的2型DM患者行NG—IVGIRT及普通葡萄糖胰岛素释放试验（IVGIRT）,8例正常对照行NG—IVGIRT。测定NG—IVGIRT及IVGIRT中服药前15min、注射葡萄糖前（0min）、结束时（2min）及后4、6、8、10min的胰岛素及血糖。结果2型DM患者0—10min胰岛素NG—IVGIRT明显高于IVGIRT;胰岛素曲线下面积（AUC）值NG—IVGIRT明显高于IVGIRT;血糖AUC值NG—IVGIRT明显低于IVGIRT。NG—IVGIRT0～10min胰岛素及胰岛素AUC值正常对照均显著高于2型DM,血糖AUC值正常对照明显低于2型DM。结论（1）NG—IVGIRT在某种程度上可以激发新诊断的2型DM患者第一时相胰岛素分泌的储备功能;（2）新诊断的2型DM患者NG—IVGIRT激发的第一时相胰岛素分泌的储备功能与正常对照相比仍有较大差距。     

Studies on the transport of insulin antibodies across the placenta to the fetus and their effect on the fetal pancreatic islet system

Summary This paper continues the preliminary communications on the insulin resistance of the offspring of insulin-resistant mothers. The investigations were carried out in guinea pigs and humans. It was shown that insulin antibodies pass into the fetal circulation which results in the appearance of passive insulin-resistance. This resistance disappears in the first weeks of life. Antibodies to bovine insulin bind in part endogenous insulin of guinea pigs, as demonstrated by marked hyperglycemia in the offspring of insulin-resistant mothers. Insulin antibodies have no noticeable effect on the architecture of the pancreas in guinea pigs in the perinatal period.This work was subsidized in part by the Polish Academy of Science.     

Serum bone morphogenetic protein 7, insulin resistance, and insulin secretion in non-diabetic individuals

This study was to explore the relationship of serum BMP7 with insulin secretion and metabolic parameters in non-diabetic individuals. Serum BMP7 concentrations positively correlated with HOMA2-%B (insulin secretion index) and fasting insulin. Our findings suggested that BMP7 may stimulate insulin secretion and improve islet cell function in humans.     

Calcium and phosphorus metabolism in insulin dependent and non-insulin dependent diabetics, well-controlled and poorly-controlled

We studied phosphorus and calcium metabolism in 50 adult insulin dependent and non insulin dependent diabetics arranged in 4 groups according to therapy and control of diabetes. We observed: a low level of blood magnesium in all diabetics a lower level of P T H, more pronounced with poorly controlled diabetes. a decrease of 1-25 (OH) 2 D levels without modification of the 25 (OH) D levels in badly controlled diabetics. This decrease may be related to the low level of PTH with a 1 alpha hydroxylation defect. These results are in favor of the hypothesis of a primary bone problem leading to the pre-senile and subclinical osteoporosis observed in diabetics. Hyperglycaemia rather than insulinopenia may be involved. Rigorous diabetes control significantly decreases all the observed differences, except the low magnesium level.     

Proinsulin and A-component antibodies in diabetics after long-term monocomponent insulin treatment

Summary In newly diagnosed diabetics treated with Monotard® (porcine monocomponent (MC) Lente insulin) for five years, no antibodies against porcine or bovine proinsulin were observed, but 2 of 13 subjects developed a-component antibodies. In newly diagnosed diabetics, treatment for the same period with conventional Lente insulin induced both proinsulin and a-component antibodies (in 5 and 8 of 10 cases, respectively). In 31 patients transferred from conventional Lente to Monotard, proinsulin and acomponent antibody levels were significantly lower than in 22 patients maintained on conventional Lente after the 5-year follow-up period. No significant differences were noted between bovine and porcine proinsulin antibodies. Insulin antibody production was similar to that of proinsulin antibody.     

Disappearance rate of insulin antibodies after discontinuing insulin treatment in 42 Type 2 (non-insulin-dependent) diabetic patients

Summary The disappearance rate of insulin antibodies was studied after cessation of insulin treatment which had been given for 3 months to 6 years in 42 Type 2 (non-insulin-dependent) diabetic patients. Insulin antibodies were measured before and 15 days after interruption of insulin treatment, and every 30 days until the disappearance of insulin antibodies. The mean ± SD value of insulin binding in the entire group before the interruption of insulin treatment was 32±14%. There was no relationship between the antibody level at that time and the duration of insulin treatment. However, the insulin antibody level was significantly higher in 17 diabetic patients on an insulin dose of >20 U/day (p<0.02) than in 25 on an insulin dose of <20 U/day (39±13% versus 28±12%). A positive correlation was found between intial insulin binding and the time required for it to fall below 10% (r = 0.74). Antibodies were absent 60 days after discontinuing insulin treatment in eight of ten subjects presenting with initial binding of <20%. In contrast, in only two of 12 patients with an initial binding of >40% were insulin antibodies detectable 150 days after discontinuation of insulin therapy. Disappearance of insulin antibodies sometimes took up to 1 year and occasionally even more than 2 years.