The development of a first myocardial infarction is associated with a large number of contributing factors. Age, male sex, hypertension, smoking, diabetes, body mass index and hypercholesterolemia are considered as established risk factors. The primary aim of the present dissertation was to evaluate whether specific biomarkers could improve the prediction of subjects at risk for a first myocardial infarction when considered in addition to established cardiovascular risk factors. The biomarkers investigated include: tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), thrombomodulin (TM), von Willebrand factor (VWF), dehydroepiandrosterone sulfate (DHEAS), lipoprotein (a) (Lp(a)), leptin, apolipoproptein A1 (ApoA1), proinsulin, homocysteine and homozygosity for the 5,10- methylenetetrahydrofolate reductase (MTHFR) C>T genotype. A secondary objective was to determine whether a first myocardial infarction leads to increased plasma homocysteine concentrations and whether the association between homocysteine and myocardial infarction was greater at follow-up compared to baseline. The study population consisted of 36 405 subjects screened and included in the Västerbotten Intervention Program and the Northern Sweden MONICA cohorts between January 1, 1985 and September 30, 1994. A nested incident case-referent study design was used. Seventy eight cases with a first myocardial infarction were identified, and from the same cohort twice as many sex and age matched referents were randomly selected. Moreover, a follow-up health survey (average 8.5 years between surveys) was conducted with 50 cases and 56 matched referents. High plasma levels of tPA and PAI-1 mass concentration, VWF, proinsulin, leptin and Lp(a) and low plasma levels of ApoA1 were associated with subsequent development of a first myocardial infarction in univariate conditional logistic regression analysis. For PAI-1 and tPA, this relation was found in both men and women. For tPA, but not for PAI-1 and VWF, this association was independent of established risk factors. In women, high plasma concentrations of TM were associated with significant increases in risk of a first myocardial infarction. No predictive values of DHEAS, homocysteine or for the point mutation C677>T in the gene for MTHFR was found regarding the risk of a first myocardial infarction. The summarised importance of haemostatic and metabolic variables (proinsulin, lipids including Lp(a) and leptin) in predicting first myocardial infarction in men, as well as possible interactions among these variables, were studied. High tPA and Lp(a) and low ApoA1 remained significant risk markers in multivariate analysis independent of established risk factors. There were non-significant synergic interactions between high Lp(a) and leptin and tPA respectively, and between high Lp(a) and low ApoA1. In the follow-up study plasma homocysteine and plasma creatinine increased significantly, and plasma albumin decreased significantly over time. Conditional univariate logistic regression indicated that high homocysteine at follow-up but not at baseline was associated with first myocardial infarction but the relation disappeared in multivariate analyses including plasma creatinine and plasma albumin. High plasma creatinine remained associated with first myocardial infarction at both baseline and follow-up. In conclusion, the present results support the hypothesis that biomarkers, in addition to the traditional cardiovascular risk factors, carry predictive information on the risk of developing a first myocardial infarction.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 6 uppsatser.

Diabetes mellitus is presently recognized as the sixth leading cause of death in the United States, affecting over 20 million people. Diabetes is a condition characterized by high blood glucose due to an insulin deficiency or resistance. Type I, which comprises 5-10% of all cases, results from the destruction of pancreatic beta cells in the islets of Langerhans. The current treatment for type I diabetes is insulin administration through injection or pump. Purification, production, and storage of this insulin proves to be quite costly. By producing biologically functional insulin with oral delivery capabilities through chloroplast genetic engineering, many of these costs could be cut back. In addition, the possibility of providing the C-peptide currently lacking in commercially available insulin becomes available. The Daniell lab inserted cholera toxin B-subunit (CTB) fused proinsulin, containing three furin cleavage sites, (CTB-pins Fx3) into the tobacco chloroplasts of Petit Havana via particle gun bombardment. The insertion of three furin cleavage sites along with fusion to CTB will enable the insulin to sustain function when orally administered. Transgenic plants from the second generation were then analyzed and tested for quantification of the CTB-pins Fx3 gene. Tobacco leaves of varying ages were compared to determine expression levels. The resulting data is pertinent for future production of both orally deliverable insulin and more cost effective injectable insulin.

<p>Defects in insulin secretion and insulin action are the major abnormalities in the development of Type 2 diabetes. Hyperinsulinemia is a risk marker for Type 2 diabetes and according to some, but not in all studies also for coronary heart disease (CHD). Conventional insulin assays measure immunoreactive insulin including proinsulin-like molecules. </p><p>Proinsulin and insulin measured by specific methods, insulin sensitivity measured by the euglycemic insulin clamp and early insulin response after a glucose challenge give more detailed information and may be better estimates of true risk for Type 2 diabetes and CHD. </p><p>This study examined relationships between proinsulin, insulin, insulin secretion and insulin sensitivity for the development of Type 2 diabetes and CHD. The investigation of the prognostic significance of proinsulin and insulin for the development of Type 2 diabetes and CHD was performed in prospective studies of 50-year and 70-year-old men in a population-based cohort. The results indicated, that increased proinsulin concentrations, was a marker of increased risk for Type 2 diabetes independent of measurements of insulin secretion and insulin sensitivity whereas insulin was not. Proinsulin was shown to be a predictor for CHD mortality and morbidity, respectively, independent of conventional risk factors, whereas insulin was not. Insulin sensitivity measured by the gold standard euglycemic insulin clamp at age 70 was a predictor of CHD morbidity, independently of established risk factors.</p><p>In summary, these data provide evidence that an increased concentration of proinsulin and not an elevated plasma insulin level per se, that constitutes the association with Type 2 diabetes and CHD and that insulin resistance per se, is associated with CHD risk.</p> / <p>Defekter i insulinsekretionen och insulinkänsligheten i målorganen för insulin är de huvudsakliga orsakerna till utvecklandet av typ-2 diabetes. Förhöjd insulinhalt i blodet indikerar nedsatt känslighet för insulin och är en riskmarkör för typ-2 diabetes men också för hjärt-kärlsjukdom enligt vissa studier.</p><p>Konventionella insulinmätmetoder är ospecifika och mäter immunoreaktivt insulin som förutom insulin också innehåller ett förstadium till insulin, proinsulin.</p><p>Proinsulin och specifikt insulin, insulinkänslighet bestämd med hyperglykemisk insulin clamp teknik och tidigt insulinsvar vid sockerbelastning ger en bättre och mer detaljerad och precis information. Dessa variabler kan därför utgöra en bättre prediktor för typ-2 diabetes och hjärt-kärlsjukdom.</p><p>I denna avhandling har proinsulin, specifikt insulin, tidigt insulinsvar vid sockerbelastning och insulinkänslighet jämförts med varandra som prediktorer för utvecklandet av typ-2 diabetes och hjärt-kärlsjukdom. Två studier har omfattat risken för diabetes och två studier risken för hjärt-kärlsjukdom. Män i medelåldern respektive i högre ålder har studerats. Studierna har utförts i en populations-baserad grupp, en kohort som har sitt ursprung i en stor hälsoundersökning som genomfördes i Uppsala 1970 till 1973.</p><p>Resultaten visar att proinsulin, i motsats till specifikt insulin, är en riskmarkör för utveckling av typ 2 diabetes, oberoende av insulinkänslighet och tidigt insulinsvar vid sockerbelastning. Vidare har visats att proinsulin i motsats till specifikt insulin är en riskmarkör för död respektive sjuklighet i hjärt-kärlsjukdom, oberoende av de kända riskfaktorerna rökning, högt blodtryck och förhöjt kolesterol. Slutligen har visats att insulinkänsligheten i sig är en riskmarkör för hjärt-kärlsjuklighet oberoende av ovanstående riskfaktorer förutom proinsulin.</p><p>Sammanfattningsvis visar resultaten i avhandlingen att det snarare är proinsulinhalten och inte insulinnivån i blodet som står för de observerade sambanden med typ 2 diabetes och hjärt-kärlsjukdom. Nedsatt känslighet för insulin i sig är förenat med ökad risk för hjärt-kärlsjukdom.</p>

<p>Most human traits and common diseases have a complex genetic makeup involving more than one gene. The work presented in this thesis investigates standing body height and the common disease type 2 diabetes mellitus (T2DM). In study I we analyzed two single nucleotide polymorphisms (SNPs) in the TCF7L2 gene that had been shown to be associated with T2DM. Analysis was performed in the ULSAM population cohort of ~1500 males. We were able to replicate the association to type 2 diabetes and in addition to that we made a novel find, showing association between the risk alleles and increased proinsulin levels. In study II we analyzed four genes identified to be associated with T2DM in a genome-wide association study. We analyzed SNPs in these genes in the ULSAM population cohort and found an association between SNPs in the HHEX gene and insulin responses and insulin levels. </p><p>The aim of studies III-V was to identify genes affecting normal variation in standing body height. Using a candidate gene approach in study III, 17 genes were screened in the ULSAM population cohort using SNPs. A suggestive association of the ESR1 gene with height was found and confirmed as significant in males from the PIVUS population cohort. In study IV, as a part of the GenomEUtwin project, we performed genetic fine mapping of a linked locus for body height on the X-chromosome. By analyzing 1377 SNPs in 780 Finnish twins, we mapped a region spanning 65kb of this locus with linkage to body height in males. This region contains the GPC3 and PHF6 genes that have known connections to syndromes were standing body height is affected. In study V significant linkage and association to standing body height in males was found for the COL1A11 gene, using population cohorts from Finland and Iceland. </p>

Defects in insulin secretion and insulin action are the major abnormalities in the development of Type 2 diabetes. Hyperinsulinemia is a risk marker for Type 2 diabetes and according to some, but not in all studies also for coronary heart disease (CHD). Conventional insulin assays measure immunoreactive insulin including proinsulin-like molecules. Proinsulin and insulin measured by specific methods, insulin sensitivity measured by the euglycemic insulin clamp and early insulin response after a glucose challenge give more detailed information and may be better estimates of true risk for Type 2 diabetes and CHD. This study examined relationships between proinsulin, insulin, insulin secretion and insulin sensitivity for the development of Type 2 diabetes and CHD. The investigation of the prognostic significance of proinsulin and insulin for the development of Type 2 diabetes and CHD was performed in prospective studies of 50-year and 70-year-old men in a population-based cohort. The results indicated, that increased proinsulin concentrations, was a marker of increased risk for Type 2 diabetes independent of measurements of insulin secretion and insulin sensitivity whereas insulin was not. Proinsulin was shown to be a predictor for CHD mortality and morbidity, respectively, independent of conventional risk factors, whereas insulin was not. Insulin sensitivity measured by the gold standard euglycemic insulin clamp at age 70 was a predictor of CHD morbidity, independently of established risk factors. In summary, these data provide evidence that an increased concentration of proinsulin and not an elevated plasma insulin level per se, that constitutes the association with Type 2 diabetes and CHD and that insulin resistance per se, is associated with CHD risk. / Defekter i insulinsekretionen och insulinkänsligheten i målorganen för insulin är de huvudsakliga orsakerna till utvecklandet av typ-2 diabetes. Förhöjd insulinhalt i blodet indikerar nedsatt känslighet för insulin och är en riskmarkör för typ-2 diabetes men också för hjärt-kärlsjukdom enligt vissa studier. Konventionella insulinmätmetoder är ospecifika och mäter immunoreaktivt insulin som förutom insulin också innehåller ett förstadium till insulin, proinsulin. Proinsulin och specifikt insulin, insulinkänslighet bestämd med hyperglykemisk insulin clamp teknik och tidigt insulinsvar vid sockerbelastning ger en bättre och mer detaljerad och precis information. Dessa variabler kan därför utgöra en bättre prediktor för typ-2 diabetes och hjärt-kärlsjukdom. I denna avhandling har proinsulin, specifikt insulin, tidigt insulinsvar vid sockerbelastning och insulinkänslighet jämförts med varandra som prediktorer för utvecklandet av typ-2 diabetes och hjärt-kärlsjukdom. Två studier har omfattat risken för diabetes och två studier risken för hjärt-kärlsjukdom. Män i medelåldern respektive i högre ålder har studerats. Studierna har utförts i en populations-baserad grupp, en kohort som har sitt ursprung i en stor hälsoundersökning som genomfördes i Uppsala 1970 till 1973. Resultaten visar att proinsulin, i motsats till specifikt insulin, är en riskmarkör för utveckling av typ 2 diabetes, oberoende av insulinkänslighet och tidigt insulinsvar vid sockerbelastning. Vidare har visats att proinsulin i motsats till specifikt insulin är en riskmarkör för död respektive sjuklighet i hjärt-kärlsjukdom, oberoende av de kända riskfaktorerna rökning, högt blodtryck och förhöjt kolesterol. Slutligen har visats att insulinkänsligheten i sig är en riskmarkör för hjärt-kärlsjuklighet oberoende av ovanstående riskfaktorer förutom proinsulin. Sammanfattningsvis visar resultaten i avhandlingen att det snarare är proinsulinhalten och inte insulinnivån i blodet som står för de observerade sambanden med typ 2 diabetes och hjärt-kärlsjukdom. Nedsatt känslighet för insulin i sig är förenat med ökad risk för hjärt-kärlsjukdom.

Most human traits and common diseases have a complex genetic makeup involving more than one gene. The work presented in this thesis investigates standing body height and the common disease type 2 diabetes mellitus (T2DM). In study I we analyzed two single nucleotide polymorphisms (SNPs) in the TCF7L2 gene that had been shown to be associated with T2DM. Analysis was performed in the ULSAM population cohort of ~1500 males. We were able to replicate the association to type 2 diabetes and in addition to that we made a novel find, showing association between the risk alleles and increased proinsulin levels. In study II we analyzed four genes identified to be associated with T2DM in a genome-wide association study. We analyzed SNPs in these genes in the ULSAM population cohort and found an association between SNPs in the HHEX gene and insulin responses and insulin levels. The aim of studies III-V was to identify genes affecting normal variation in standing body height. Using a candidate gene approach in study III, 17 genes were screened in the ULSAM population cohort using SNPs. A suggestive association of the ESR1 gene with height was found and confirmed as significant in males from the PIVUS population cohort. In study IV, as a part of the GenomEUtwin project, we performed genetic fine mapping of a linked locus for body height on the X-chromosome. By analyzing 1377 SNPs in 780 Finnish twins, we mapped a region spanning 65kb of this locus with linkage to body height in males. This region contains the GPC3 and PHF6 genes that have known connections to syndromes were standing body height is affected. In study V significant linkage and association to standing body height in males was found for the COL1A11 gene, using population cohorts from Finland and Iceland.

Type 1 diabetes (T1D) is a chronic autoimmune disease targeted against the pancreatic β-cells. Proinflammatory cytokines are considered to play a major role in the destruction of the insulin-producing β-cells. This thesis studied strategies to counteract proinflammatory cytokines in experimental T1D. Both animal models for T1D as well as β-cell preparations exposed in vitro to putative noxious conditions were examined. In the first study we observed that cytokine treatment of mouse pancreatic islets lacking inducible nitric oxide synthase (iNOS) induced a prolongation of the early stimulatory phase of glucose stimulated insulin secretion. Various experiments led to the conclusion that this prolonged stimulatory effect may involve the DAG/PLD/PKC pathway. Next, we transplanted mouse islets deficient in iNOS to spontaneously diabetic NOD mice. We observed a normalization of hyperglycemia but not a delayed allograft rejection compared to transplanted wild type islets. Thus, absence of iNOS in the graft was not sufficient to prolong allograft survival. In paper III we found that sustained glucose stimulation of rat pancreatic islets was coupled to a decreased conversion of proinsulin to insulin. Islet treatment with IL-1β was also coupled to a decreased proinsulin conversion. Islet proconvertase activity may be a target in islet damage. In paper IV prolactin (PRL) was administered to mice in the multiple low dose streptozotocin model and we observed that PRL enhanced a Th2 response. This may contribute to the protective action by PRL in this model of autoimmune T1D. Finally, by examining β-cells overexpressing Suppressor of cytokine signalling 3 (SOCS-3) it was found that this could inhibit IL-1β induced signalling through the NF-κB and MAPK pathways. SOCS-3 overexpression also inhibited apoptosis induced by cytokines in primary β-cells. Lastly, we demonstrated that SOCS-3 transgenic islets were protected in an allogeneic transplantation model.

In the last decades our knowledge concerning cardiovascular risk factors has grown rapidly through results from longitudinal studies. However, despite new treatment, in Western countries coronary heart disease remains the leading cause of death and stroke is still the leading cause of severe disability. The studies reported in these papers examine the relationships between stroke/transient ischaemic attack (TIA) and a number of different factors measured on two different occasions in men born in Uppsala 1920-1924 and are epidemiological in their character. The findings indicate that in addition to already established risk factors, indices of an unhealthy dietary fat intake and high serum lipoprotein(a) are independent predictors of stroke/TIA. Among different glucometabolic variables a low insulin sensitivity index derived from the euglycaemic insulin clamp and proinsulin carries a high predictive value for later stroke, independently of diabetes. Moreover, cognitive test performance measured with Trail Making Test B at age 70 is a strong and independent predictor of brain infarction, indicating that the risk is already increased in the subclinical phase of milder cognitive dysfunction. Performance at a pre-stroke Trail Making Test is also of predictive value for mortality after first-ever stroke/TIA, but none of the studied pre-stroke variables or cognitive tests was found to be related to dependency after an event. In summary these studies provide further knowledge about predictors of stroke and of mortality after first-ever stroke. They also indicate the possible importance of new markers of risk, such as the level of lipoprotein(a), profile of fatty acids in the diet, low insulin sensitivity derived from clamp investigations, level of proinsulin, and cognitive performance measured with Trail Making Tests.