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PubMed1997

Impaired lymphokine secretion in anergic CD4+ T cells leads to defective help for B cell growth and differentiation.

The ability of anergic helper T cells to interact with resting B cells was examined in vitro. B cell growth and differentiation in cocultures were found to be dependent on the expression of CD40 ligand (CD40L) on the cloned T cells, and the expression of this molecule was only marginally blocked by the induction of anergy. In contrast, secretion of IL-3, IL-4, IL-5, and IL-6 within the cocultures was found to be significantly reduced following the induction of anergy, and this correlated with the development of a 3- to 10-fold decrease in the ability of the T cells to induce B cell proliferation and IgG secretion. In contrast to the B cells, the activation of the T cells in these cocultures did not result in proliferation; thus, the effects of T cell anergy observed on the B cell responses were independent of an ability of clonal anergy to block T cell clonal expansion. In one T cell clone (E6), lymphokine production was reduced in part because of an increased propensity to undergo apoptosis; nevertheless, two other clones (A.E7 and 16B.2) showed no reduced viability after anergy induction. Finally, the addition of rIL-2 to the anergic T cells significantly improved their helper activity relative to control cells; this was associated with a partial reversal of the IL-3, - 4, and -5 production defects. Therefore, clonal anergy can interfere with the delivery of helper lymphokines by T cells, resulting in a decreased capacity to stimulate the growth and differentiation of B cells.

Animals↗
PubMed2002

Response of von Willebrand factor parameters to desmopressin in patients with type 1 and type 2 congenital von Willebrand disease: diagnostic and therapeutic implications.

In the present study, we prospectively evaluated the contribution of the von Willebrand factor collagen-binding activity (vWF:CBA) assay, vWF multimeric analysis, and the response to intravenous desmopressin (DDAVP) to correctly diagnose and classify congenital von Willebrand disease (CvWD) in 24 probands with mild to moderate type 1 vWD, 6 probands with severe CvWD type 1, and 12 probands with type 2 CvWD. CvWD type 1 of mild to moderate severity is featured by proportionally decreased levels of vWF antigen (vWF:Ag), vWF ristocetin cofactor activity (vWF:RCof), and vWF:CBA between 0.20 and 0.60 u/mL and a normal response to DDAVP of factor (F) VIIIc and all vWF parameters. Severe type 1 CvWD with vWF parameters below 0.10 or 0.20 u/mL is associated with a decreased response to DDAVP of all vWF parameters, indicating a defective synthesis or secretion vWF by endothelial cells, or both. CvWD 2M may present as severe type 1 CvWD, as type 1 "platelet-discordant" CvWD, or with the combination of a discrepant vWF:RCof/Ag ratio and the presence of all vWF multimers. Ristocetin-induced platelet aggregation (RIPA) is normal in type 1 CvWD. CvWD 2M is typically featured by decreased RIPA, normal or near normal vWF multimers, and no or only a poor response to DDAVP of vWF:RCof as compared with a fairly good response to DDAVP of vWF:Ag and vWF:CBA. CvWD Vicenza is characterized by unusually large vWF multimers and very low levels of FVIIIc, vWF:Ag, and vWF:RCof. CvWD Vicenza differs from CvWD 2M because the vWF:RCof/Ag ratios are completely normal before and after DDAVP; the response to DDAVP is equally good for FVIIIc, vWF:Ag, vWF:RCof, and vWF:CBA and is followed by very short half-life times for FVIIIc and all vWF parameters. Pertinent findings in type 2A and 2B CvWD included prolonged Ivy bleeding time (BT), low vWF:RCof/Ag and vWF:CBA ratios, absence of the high vWF multimers, and, depending on the severity of the absence of intermediate vWF multimers, pronounced increase of low vWF multimers and vWF degradation products because of increased proteolysis of the high and intermediate vWF multimers. RIPA is normal in CvWD 2A and increased in CvWD 2B. The response to DDAVP in CvWD 2A is normal for FVIIIc and vWF:Ag but is transient with partial correction and short half-life times of vWF:CBA and vWF:RCof. DDAVP does not correct BT and multimeric patterns in CvWD type 2B, despite significant increase of vWF parameters. CvWD types 2C, 2D, and 2E are featured by very low functional vWF parameters, the presence of typically abnormal vWF multimers, a very poor response of vWF:CBA, a decreased response of vWF:RCof, and a fairly good response of vWF:Ag to DDAVP with no correction of prolonged Ivy BT and no correction of the vWF multimeric pattern as the consequence of a multimerization or dimerization defect of the vWF molecules. CvWD type 2N usually presents with much lower levels for FVIIIc as compared with vWF, normal Ivy BT, and normal vWF multimeric pattern. The response to DDAVP is normal for all vWF parameters but is decreased for FVIIIc with shortened half-life times.

Adult↗
PubMed1989

Luteal phase deficiency: characterization of reproductive hormones over the menstrual cycle.

The recurrent deficiency of progesterone (P) secretion by the corpus luteum has been associated with infertility and habitual abortion and given the clinical diagnosis of luteal phase deficiency (LPD). There is evidence that both follicular and luteal phase abnormalities can result in LPD cycles. In this study we have examined reproductive hormone levels and preovulatory follicular size in women with LPD (n = 10). For the purposes of this study, LPD was determined by an endometrial biopsy in the studied cycle that was more than 2 days out of phase. These biopsies were performed in women with infertility or habitual abortion who exhibited an out of phase biopsy in a prior cycle. The control group consisted of 28 normal women. Daily serum levels of the following hormones were determined in each subject: LH and FSH [immuno- and bioactive (LH-immuno and LH-bio)], P, estradiol (E2), and inhibin. The LPD women exhibited significant decreases in integrated luteal phase levels of inhibin [10,615 +/- 898 vs. 13,560 +/- 662 (U/L).days; P less than 0.02] and E2 [5,015 +/- 275 vs. 6,435 +/- 393 (pmol/L).days (1366 vs. 1753 (pg/mL).days); P less than 0.05] in addition to the expected decrease in P [280 +/- 23 vs. 420 +/- 23 (nmol/L).days (88 vs. 132 (ng/mL).days); P less than 0.01]. On days 6-11 after the LH surge (day 0), there was a significant (P less than 0.05) decrease in mean LH-bio levels in LPD compared with those in normal women (146 +/- 26 vs. 212 +/- 24 micrograms/L). The midcycle LH surge was deficient in LPD when both LH-immuno [482 +/- 30 vs. 672 +/- 43 (micrograms/L).days; P less than 0.01] and LH-bio [1711 +/- 179 vs. 2248 +/- 226 (micrograms/L).days; P less than 0.05] levels were compared with normal values. When comparing the follicular phase in LPD with that in normal women, similar follicle size, peak and integrated E2 levels, and mean LH and FSH (immuno and bio) levels were found. The only follicular phase abnormality noted in this study was decreased mean levels of serum inhibin in the early and midfollicular phases (221 +/- 19 vs. 308 +/- 25 U/L; P less than 0.01). In this group of women with LPD, low levels of inhibin in the follicular phase were consistent with the concept of a defect in function of the preovulatory follicle, possibly as a result of previously described defects in gonadotropin secretion in this condition.(ABSTRACT TRUNCATED AT 400 WORDS)

Abortion, Habitual↗
PubMed2002

Early changes in beta-cell function and insulin pulsatility as predictors for type 2 diabetes.

Peripheral insulin concentrations oscillate because of insulin secretory bursts every 6-10 min, which are the main source of overall insulin release. Regulation of insulin secretion occurs by modification of the mass and to some extent the frequency of the individual insulin secretory bursts. This oscillatory pattern, which is important for insulin action, is observed at the level of the individual beta-cells and in the islets, both in vitro (in the isolated perfused pancreas) and in vivo. It has therefore been suggested that beta-cells act as pacemakers and that co-ordination among islets is achieved by a neuronal network within the pancreas. Type 2 diabetes mellitus is characterised both by impaired release of insulin and by resistance to the action of insulin. Routine screening procedures for insulin secretion yield little predictive value for later development of diabetes but more sophisticated methods using time-series analysis of diurnal, ultradian and rapid oscillatory insulin secretion reveal the presence of profound defects in glucose-intolerant individuals. Furthermore, studies of rapid pulsatile insulin secretion have revealed defects in glucose-tolerant first-degree relatives of patients with Type 2 diabetes. Application of repeated minimal glucose infusions has further improved the discrimination between insulin release in health and diabetes, suggesting that this method may be suitable for smaller prospective studies of the development of diabetes. Repaglinide, a novel prandial glucose regulator, improves the insulin secretory burst mass in healthy people.

Carbamates↗
PubMed1995

[Role of free fatty acids in the insulin resistance of non-insulin-dependent diabetes].

Non-insulin-dependent diabetes (NIDDM) is characterized by overproduction of glucose, decreased effects of insulin on glucose utilization and production, and a defect in glucose-induced insulin secretion. NIDDM is also associated with defects in fatty acid metabolism, i.e. enhanced lipolysis and impaired suppression of adipose tissue lipolysis in response to insulin, and increased plasma free fatty acid levels. It has been suggested that the "glucose-fatty acid cycle" is enhanced in NIDDM and could contribute to disturbed glucose homeostasis. Although the use of intralipid + heparin infusion and inhibitors of lipolysis or fatty acid oxidation indicates that the glucose-fatty acid cycle exists both in normal and NIDDM subjects, it does not seem to be the primary cause of distributed glucose homeostasis in lean NIDDM subjects or their first-degree relatives. However, the glucose-fatty acid cycle could contribute to overproduction of glucose (by stimulating gluconeogenesis) and muscle insulin resistance in obese NIDDM subjects. Studies performed in the rat suggest that impaired glucose-induced insulin secretion could also be related to chronic exposure of pancreatic beta cells to elevated plasma free fatty acid levels. The role of the glucose-fatty acid cycle in normal subject must be clarified, and its contribution to decreased glucose-induced insulin secretion in NIDDM requires further investigation.

Diabetes Mellitus, Type 2↗
PubMed1993

[Cellular expression of CFTR in cystic fibrosis: defective cyclic AMP-dependent regulation of glycoconjugate secretion in cystic fibrosis fetal tracheal epithelial cells transfected by SV40 large T oncogene].

Epithelial tracheal cells isolated from two fetuses with cystic fibrosis (CF) and non-CF fetus (control) were transfected with a plasmid vector recombined with the large T oncogene of SV40. All transfected cells expressed SV40 antigen and exhibited an epithelial morphology (junctional complex, cytokeratins). CFT cells retained the mutations of the CF gene, one heterozygous for the S549N/N1303K substitutions (CFT-1 cells), the other homozygous for the deletion delta F508 (CFT-2 cells). Accordingly, these CFT cells exhibited the defective beta-adrenergic regulation of chloride conductance. We compared the responsiveness of control (NT-1 cells) and CF cells (CFT-1 and CFT-2 cells) to agonists of the protein kinase A (PKA)-dependent pathway for stimulation of glycoconjugate secretion. We show that the isoproterenol (10(-5) M) and forskolin (10(-5) M) markedly increased the cAMP content and the PKA activity of all three cell lines. In contrast, these effectors produced an increase in glycoconjugate secretion in control cells, but not in CFT-1 and CFT-2 cells. In conclusion, our results indicate that CFT cells do not respond to agonists of the PKA-dependent pathway for stimulation of both glycoconjugate secretion and chloride transport, which suggests the involvement of CFTR in these two processes.

Cells, Cultured↗
PubMed1989

Abnormal zinc content in human milk. Risk for development of nutritional zinc deficiency in infants.

An abnormally low concentration of zinc in mother's milk has been associated with clinical nutritional zinc deficiency in premature and term newborns. Defective mammary gland secretion of zinc was suggested as the causative factor. We investigated whether low milk zinc concentration might be reflected in an abnormality of the distribution of zinc between casein, whey, and fat components of the milk, in a reduction in the levels of milk citrate, a zinc-binding ligand, or in abnormal levels of copper and iron. Milk from mothers of four low-birth-weight infants was identified as being deficient in zinc content for the lactational stage. One infant had clinical signs of nutritional zinc deficiency. For two of the three infants with subclinical deficiencies in whom balance study data were available, the apparent zinc balance was negative (-5.7 and -6.0 mumol/kg per day). These milks were examined for content and distribution of zinc, copper, and iron, and citrate concentration. Although total zinc concentration (4.5 to 17.2 mumol/L) was below the 95% prediction interval (15.2 to 59.7 mumol/L) for the lactational stage, the distribution of zinc was normal between milk components. Levels of citrate (1.46 to 5.13 mmol/L) were also within normal limits, as were levels of copper (0.27 to 0.85 mumol/L and iron (0.41 to 1.13 mumol/L). We concluded that there was no indirect evidence of a secretory abnormality in milk zinc deficiency, but speculated that there might instead be an abnormality of zinc uptake by the mammary gland from the plasma.

Breast Feeding↗
PubMed1997

The postprandial state: mechanisms of glucose intolerance.

Defective carbohydrate metabolism is central to the pathogenesis of non-insulin-dependent diabetes mellitus (NIDDM) and impaired glucose tolerance (IGT). Plasma glucose concentrations are determined by a balance between glucose entry into and removal from the circulation. In non-diabetic individuals, an oral glucose load triggers a rapid insulin secretory response. Insulin suppresses hepatic glucose release and stimulates peripheral glucose uptake, thereby limiting the postprandial rise in plasma glucose concentration. In addition, the term 'glucose effectiveness' describes how glucose regulates its own metabolism. In individuals with NIDDM or IGT, the beta-cell response to glucose is impaired, the incretin effect is reduced, hepatic and peripheral tissues are resistant to insulin, and glucose effectiveness may be impaired. Furthermore, disturbances in free fatty acid metabolism may alter intracellular glucose metabolism. The relative contributions of these defects to postprandial hyperglycaemia remain to be determined. However, the defects in insulin secretion and insulin action are central to understanding diabetic and prediabetic states.

Blood Glucose↗
PubMed2000

Microsomal triglyceride transfer protein (MTP) gene mutations in Canadian subjects with abetalipoproteinemia.

Abetalipoproteinemia (ABL) is an extremely rare autosomal recessive disorder, which is characterized by defective assembly and secretion of plasma apolipoprotein (apo) B-containing lipoproteins. ABL results from mutations in the gene encoding the microsomal triglyceride transfer protein (MTP). We sequenced the MTP gene in six Canadian subjects with ABL, of whom four were found to be simple homozygotes and two were found to be compound heterozygotes for MTP gene mutations. Of the 8 MTP gene mutations identified, 6 had not been previously reported, including two new nonsense mutations (K448X and K842X), two new missense mutations (S590I and G746E), one new frameshift mutation (1820del1) and one new splice donor site mutation (G1770A). Despite appropriate treatment with high doses of fat-soluble vitamins in all subjects, there was a wide variation in the progression and severity of the clinical phenotypes. For example, the presence of severe retinopathy and neuropathy did not correlate with the type and position of the mutation, but rather with the age at diagnosis and onset of treatment with fat-soluble vitamins. These findings suggest that genetic and non-genetic factors can modulate the clinical impact of mutant MTP in ABL patients.

Abetalipoproteinemia↗
PubMed1981

Malignant interstitial cell carcinoma of the testis: report of two cases with steroid synthetic profiles, response to therapy, and review of the literature.

Two cases of malignant interstitial cell carcinoma of the testis are reported. The first patient had no evidence of a virilizing syndrome. Basal plasma testosterone (T) was decreased, whereas plasma luteinizing hormone, estrone (E1), and androstenedione were elevated. These findings were diagnostic of a defect in T secretion as a result of a partial 17-hydroxysteroid dehydrogenase deficiency as seen in male pseudohermaphroditism. In the second patient, showing gynecomastia and atrophic testis, endocrine studies revealed high plasma T and estradiol (E2); all measured delta 4 and delta 5 precursors of T were elevated resembling the pattern seen in virilizing adrenal carcinomas. Both patients were treated with radiotherapy without demonstrable effect. Chemotherapy--consisting of a combination of cis-platinum, vinblastine, and bleomycin; then cyclophosphamide, doxorubicin, and vincristine; and finally o,p'-DDD--was unsuccessful in reducing tumor bulk. Since malignant Leydig cell carcinomas are rare, this paper reviews the literature and makes recommendations concerning treatment.

17-Ketosteroids↗
PubMed1992

Defective biliary excretion of epinephrine metabolites in mutant (TR-) rats: relation to the pathogenesis of black liver in the Dubin-Johnson syndrome and Corriedale sheep with an analogous excretory defect.

Dubin-Johnson patients, mutant Corriedale sheep and TR- and EHBR mutant rats have recessively inherited defective bile canalicular secretion of many nonbile acid organic anions. The human and ovine mutants have black livers and lysosomal pigment accumulation. The livers in TR- and EHBR mutant rats are not black, and sparse lysosomal pigment accumulation is seen. Previously, we postulated that the unidentified pigment in the Dubin-Johnson syndrome results from the accumulation of tyrosine, phenylalanine and tryptophan metabolites, such as metanephrine, which are normally secreted in bile as organic anions. We tested this hypothesis in TR- rats. 3H-epinephrine was injected intravenously; control rats secreted 2.80% +/- 0.52% of the injected dose in bile as compared with 0.19% +/- 0.07% in TR- rats. From 82% to 90% of biliary radioactivity was due to polar conjugates in control rats and mutant rats. TR- rats retained more of the injected dose in the liver, particularly in lysosomes, and secreted more in urine than did control rats. After feeding control and TR- rats for 4 mo with a rat chow diet supplemented with 4% tyrosine, tryptophan and phenylalanine, the liver did not become grossly black; however, histological and electron microscopic study revealed dense lysosomal pigment accumulation in TR- rats. Intraportal injection of metanephrine resulted in the appearance of black liver in TR- rats that persisted for at least 2 hr and was not associated with pigment accumulation by light or electron microscopic examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Distinct endoplasmic reticulum stress responses are triggered during human liver transplantation.

Injury due to cold ischaemia-reperfusion (IR) represents a major cause of primary graft non-function following human liver transplantation. This major cellular response translates into a dramatic decrease in intracellular ATP concentration during the ischaemic phase, thus sensitizing cells to reperfusion shock. We postulated that IR-induced cellular damage might cause alterations of the secretory pathway, particularly at the level of endoplasmic reticulum (ER) function. Under these circumstances, the ER triggers an adaptive response named the 'unfolded protein response' (UPR). In this study, we show that the expression of BiP, CHOP/GADD153 and GADD34, known to be induced specifically upon ER stress, are differentially affected upon IR, thus suggesting that distinct ER stress responses are activated during each phase of transplantation. With an approach combining semi-quantitative RT-PCR and immunoblotting using phospho-specific antibodies, we show that the IRE-1 pathway is activated upon early ischaemia and, in a second phase, upon early reperfusion. This occurs through the atypical splicing of XBP-1 mRNA, its translation into a transcriptionally active XBP-1 protein and the subsequent increase in EDEM mRNA expression, and may also contribute to the observed reperfusion-induced activation of MAPK/SAPK. In contrast, we demonstrate that the PERK pathway, leading to inhibition of cap-dependent translation, is mainly activated upon reperfusion, as shown by PERK and eIF2alpha phosphorylation. PERK activation is detected restrictively in sinusoidal endothelial cells and could contribute to the exaggerated sensivity of this liver cell type to IR injury. These results correlate well with the observed defect in protein secretion and suggest that the biphasic ER stress response may influence liver secretory functions and, as a consequence, condition liver transplantation outcomes.

Endoplasmic Reticulum↗
PubMed1991

Fiber-optic measurement of intracellular pH in intact rat liver using pH-sensitive dyes.

The pH-sensitive fluorescent dye 1,3-dihydroxy-pyrene-6,8-disulfonic acid (DHPDS) was used to measure intracellular pH (pHi) from the surface fluorescence of the isolated perfused rat liver. Monochromatic light from a fluorometer was focused on the liver with a fiber optic, emitted light was collected with a second fiber bundle and returned to the spectrometer. To correct for changes in intracellular dye concentration, the excitation wavelength was changed between the pH-sensitive excitation peak wavelength and the isosbestic wavelength, then a ratio was computed between fluorescence intensities at these two wavelengths. Intracellular calibration of the dye was performed by clamping the intracellular to the extracellular pH with H+/K(+)-ionophore Nigericin. This method was used to monitor transient changes in intracellular pH caused either by addition and removal of NH4Cl or by changing perfusate CO2 and HCO3- concentrations while keeping their ratio constant. The effects of these maneuvers on bileflow were studied, too. Data obtained in the perfused liver were in good agreement with those obtained in isolated liver cells except that the steady-state pHi (7.46 +/- 0.02) was slightly higher than reported values. Measurements in livers of mutant TR- rats that are defective of dye secretion revealed similar pHi values, indicating that secretion of the dye into bile canaliculi did not affect measurements. The technique appears adequate to measure pHi in the liver and will allow to study pH regulatory mechanisms in the intact organ.

Animals↗
PubMed1995

Insulin regulation of glucose turnover and lipid levels in obese children with fasting normoinsulinaemia.

To evaluate the early metabolic alterations induced by obesity, we studied glucose turnover and lipid levels in obese children with fasting normoinsulinaemia. Two experimental protocols were carried out. Protocol I consisted of a euglycaemic glucose clamp at two rates of insulin infusion. Protocol II was similar to protocol I except for a variable lipid infusion used to maintain basal non-esterified fatty acid (NEFA) levels. During protocol I, the glucose disappearance rates were lower in obese children, while no differences were found in hepatic glucose release. NEFA response to insulin was not substantially altered in obese children either at low or high insulin infusion. During protocol II, the NEFA clamp induced a 25% reduction in peripheral insulin sensitivity in control children whereas no changes were observed in obese children. Interestingly, lipid infusion in control children was not sufficient to reproduce the same degree of insulin resistance observed in obese children, suggesting that NEFA are only one of the determinants of insulin resistance at this stage of obesity. In conclusion, the present study provides a portrait of glucose metabolism and lipid levels in normoinsulinaemic obese children. Our results document that peripheral insulin resistance is the first alteration at this stage of obesity, whereas an increase in insulin secretion and a defect in the inhibition of hepatic glucose release by insulin may develop at a later stage. In addition, primarily receptor and post-receptor defects and some alterations of NEFA metabolism are likely to coexist in the induction of insulin resistance at this stage of obesity.

3-Hydroxybutyric Acid↗
PubMed1978

The response of gastric inhibitory polypeptide (GIP) and insulin to glucose in duodenal ulcer patients.

The response of Gastric Inhibitory Polypeptide (GIP) and insulin to a 50 g oral glucose tolerance test (OGTT) and an intravenous glucose infusion (IVGI), which copied the changes in plasma glucose concentrations during the OGTT, were measured in 10 patients with duodenal ulcer and in 10 healthy control subjects. The mean responses of GIP and insulin to OGTT were significantly increased in the ulcer patients. During IVGI the responses were normal. The degree of increased GIP response in the patients was positively correlated with the plasma glucose increase during the OGTT. It is postulated that the increased GIP secretion is related to a faster glucose absorption due to rapid gastric emptying in duodenal ulcer patients. No correlation was found between basal and peak gastric acid output and the GIP response in the patients. The data demonstrate that GIP secretion is not defective in duodenal ulcer patients.

Adult↗
PubMed2004

Missense mutations in the human insulin promoter factor-1 gene are not a common cause of type 2 diabetes mellitus in Taiwan.

Type 2 diabetes mellitus (T2DM) is a common metabolic disorder characterized by a hyperglycemia resulting from defect in insulin secretion and insulin action. Recent studies showed that dominant negative mutations in the insulin promoter factor-1 (IPF-1), a pancreatic beta-cell specific transcription factor, cause maturity-onset diabetes of the young (MODY), a subtype of T2DM with early onset and monogenic autosomal inheritance. In addition to MODY, IPF-1 mutations are suggested to predispose to common late-onset T2DM with different penetration of the mutations reflected in their in vitro activity. Thus, we investigated IPF-1 C18R, Q59L, D76N and R197H mutations in Taiwanese patients with common late-onset T2DM, because research into IPF-1 variants in Taiwanese diabetic patients--a population with the lowest range of diabetic incidence--has never been documented. Peripheral blood samples were collected and genomic DNA was extracted from 434 patients with T2DM and 194 non-diabetes control study subjects. IPF-1 genetic variations were analyzed by PCR and restriction fragment length polymorphism (RFLP) analysis. We did not find any of these four IPF-1 mutations in our patients. Our results suggested that IPF-1 mutations were not a common cause associated with Taiwanese T2DM.

Age of Onset↗
PubMed2003

Proinsulin and acute insulin response independently predict Type 2 diabetes mellitus in men--report from 27 years of follow-up study.

AIMS/HYPOTHESIS: Defects in insulin secretion and insulin action, resulting in compensatory hyperinsulinaemia, are the major abnormalities in the development of Type 2 diabetes mellitus (Type 2 diabetes). The most frequently used conventional immunoreactive assays for insulin cross-react with proinsulin. In short-term studies (<5 years), proinsulin predicts the development of Type 2 diabetes. We studied, with a 27-year follow-up, the longitudinal relationships between intact proinsulin, 32-33 split proinsulin, specific and immunoreactive insulin (IRI), acute insulin response (AIR) after an intravenous glucose load and the development of Type 2 diabetes in a population-based cohort of 50-year-old men. METHODS: Fasting peptide concentrations were measured in plasma samples, stored since 1970-73 using specific two-site immunometric assays. IRI was measured at baseline using radioimmunoassay. Associations between development of Type 2 diabetes and predictor variables, were analysed with logistic regression. Results are shown as odds ratios (ORs) with their 95% confidence intervals (CIs) for a one standard deviation increase in a predictor variable. RESULTS: Cumulative incidence of Type 2 diabetes was 33% over 27 years of follow-up. Intact proinsulin (OR, 1.57, CI, 1.16-2.14), and 32-33 split proinsulin (OR, 1.70, CI, 1.20-2.39) were associated with development of Type 2 diabetes, independent of AIR, adjusted for BMI and fasting glucose, whereas specific insulin was not (OR, 1.31, CI, 0.98-1.77), nor was IRI (OR, 1.25, CI, 0.96-1.63). Proinsulin and AIR interacted in the development of Type 2 diabetes (p<0.05). CONCLUSION/INTERPRETATION: Proinsulin predicts the development of Type 2 diabetes mellitus over a 27-year period.

Cohort Studies↗
PubMed2004

Characterisation of subjects with early abnormalities of glucose tolerance in the Stockholm Diabetes Prevention Programme: the impact of sex and type 2 diabetes heredity.

AIMS/HYPOTHESIS: We evaluated the impact of sex and type 2 diabetes heredity on the prevalence and pathogenesis of early abnormalities of glucose homeostasis in subjects participating in the Stockholm Diabetes Prevention Programme. METHODS: A sample of 3,128 men and 4,821 women, of whom approximately half had a family history of type 2 diabetes (FHD) was categorised according to an OGTT: NGT, IFG, IGT, combined glucose intolerance and type 2 diabetes. The homeostasis model assessment was used to determine insulin sensitivity and beta cell function. RESULTS: Prevalence of early abnormalities of glucose metabolism was two to three times higher in subjects with FHD and two to three times higher in men compared to women. Both maternal and paternal heredity of type 2 diabetes were associated with an increased risk of having early abnormalities of glucose metabolism. However, in women with type 2 diabetes heredity on the father's side seems to have less impact on an increased risk of having type 2 diabetes. Both waist circumference and systolic blood pressure were increased in subjects with abnormalities of glucose homeostasis, whereas insulin sensitivity and beta cell function were decreased. Subjects with IFG had more pronounced impairment of beta cell function and insulin sensitivity than subjects with IGT. CONCLUSION/INTERPRETATION: An FHD and male sex increased the prevalence of abnormalities of glucose homeostasis. Subjects with IFG had more pronounced defects of insulin secretion and action than subjects with IGT.

Blood Glucose↗