Determinants of Coronary and Carotid Atherosclerosis in Finnish Patients with Clinically Suspected Coronary Artery Disease. A Quantitative Angiography and Ultrasound Study

Background. Cardiovascular disease (CVD) remains the most serious threat to life and health in industrialized countries. Atherosclerosis is the main underlying pathology associated with CVD, in particular coronary artery disease (CAD), ischaemic stroke, and peripheral arterial disease. Risk factors play an important role in initiating and accelerating the complex process of atherosclerosis. Most studies of risk factors have focused on the presence or absence of clinically defined CVD. Less is known about the determinants of the severity and extent of atherosclerosis in symptomatic patients. Aims. To clarify the association between coronary and carotid artery atherosclerosis, and to study the determinants associated with these abnormalities with special regard to novel cardiovascular risk factors. Subjects and methods. Quantitative coronary angiography (QCA) and B-mode ultrasound were used to assess coronary and carotid artery atherosclerosis in 108 patients with clinically suspected CAD referred for elective coronary angiography. To evaluate anatomic severity and extent of CAD, several QCA parameters were incorporated into indexes. These measurements reflected CAD severity, extent, and overall atheroma burden and were calculated for the entire coronary tree and separately for different coronary segments (i.e., left main, proximal, mid, and distal segments). Maximum and mean intima-media thickness (IMT) values of carotid arteries were measured and expressed as mean aggregate values. Furthermore, the study design included extensive fasting blood samples, oral glucose tolerance test, and an oral fat-load test to be performed in each participant. Results. Maximum and mean IMT values were significantly correlated with CAD severity, extent, and atheroma burden. There was heterogeneity in associations between IMT and CAD indexes according to anatomical location of CAD. Maximum and mean IMT values, respectively, were correlated with QCA indexes for mid and distal segments but not with the proximal segments of coronary vessels. The values of paraoxonase-1 (PON1) activity and concentration, respectively, were lower in subjects with significant CAD and there was a significant relationship between PON1 activity and concentration and coronary atherosclerosis assessed by QCA. PON1 activity was a significant determinant of severity of CAD independently of HDL cholesterol. Neither PON1 activity nor concentration was associated with carotid IMT. The concentration of triglycerides (TGs), triglyceride-rich lipoproteins (TRLs), oxidized LDL (oxLDL), and the cholesterol content of remnant lipoprotein particle (RLP-C) were significantly increased at 6 hours after intake of an oral fatty meal as compared with fasting values. The mean peak size of LDL remained unchanged 6 hours after the test meal. The correlations between total TGs, TRLs, and RLP-C in fasting and postprandial state were highly significant. RLP-C correlated with oxLDL both in fasting and in fed state and inversely with LDL size. In multivariate analysis oxLDL was a determinant of severity and extent of CAD. Neither total TGs, TRLs, oxLDL, nor LDL size were linked to carotid atherosclerosis. Insulin resistance (IR) was associated with an increased severity and extent of coronary atherosclerosis and seemed to be a stronger predictor of coronary atherosclerosis in the distal parts of the coronary tree than in the proximal and mid parts. In the multivariate analysis IR was a significant predictor of the severity of CAD. IR did not correlate with carotid IMT. Maximum and mean carotid IMT were higher in patients with the apoE4 phenotype compared with subjects with the apoE3 phenotype. Likewise, patients with the apoE4 phenotype had a more severe and extensive CAD than individuals with the apoE3 phenotype. Conclusions. 1) There is an association between carotid IMT and the severity and extent of CAD. Carotid IMT seems to be a weaker predictor of coronary atherosclerosis in the proximal parts of the coronary tree than in the mid and distal parts. 2) PON1 activity has an important role in the pathogenesis of coronary atherosclerosis. More importantly, the study illustrates how the protective role of HDL could be modulated by its components such that equivalent serum concentrations of HDL cholesterol may not equate with an equivalent, potential protective capacity. 3) RLP-C in the fasting state is a good marker of postprandial TRLs. Circulating oxLDL increases in CAD patients postprandially. The highly significant positive correlation between postprandial TRLs and postprandial oxLDL suggests that the postprandial state creates oxidative stress. Our findings emphasize the fundamental role of LDL oxidation in the development of atherosclerosis even after inclusion of conventional CAD risk factors. 4) Disturbances in glucose metabolism are crucial in the pathogenesis of coronary atherosclerosis. In fact, subjects with IR are comparable with diabetic subjects in terms of severity and extent of CAD. 5) ApoE polymorphism is involved in the susceptibility to both carotid and coronary atherosclerosis.

Major histocompatibility complex and coronary artery disease: Special emphasis on Chlamydia pneumoniae, and periodontitis

Most of the genes in the MHC region are involveed in adaptive and innate immunity, with essential function in inflammatory reactions and in protection against infections. These genes might serve as a candidate region for infection and inflammation associated diseases. CAD is an inflammatory disease. The present set of studies was performed to assess whether the MHC region harbors genetic markers for CAD, and whether these genetic markers explain the CAD risk factors: e.g., C. pneumoniae, periodontitis, and periodontal pathogens. Study I was performed using two separate patient materials and age- and sex-matched healthy controls, categorizing them into two independent studies: the HTx and ACS studies. Both studies consistently showed the HLA-A3– B35– DR1 (35 ancestral haplotype) haplotype as a susceptible MHC genetic marker for CAD. HLA-DR1 alone was associated not only with CAD, but also with CAD risk factor diseases, e.g., diabetes mellitus, and hyperlipidemia. The ACS study further showed the HLA-B*07 and -DRB1*15 -related haplotype as a protective MHC haplotype for CAD. Study II showed that patients with CAD showed signs of chronic C. pneumoniae infection when compared to age- and sex-matched healthy controls. HLA-B*35 or -related haplotypes associated with the C. pneumoniae infection markers. Among these haplotype carriers, males and smokers associated with elevated C. pneumoniae infection markers. Study III showed that CAD patients with periodontitis had elevated serum markers of P. gingivalis and occurrence of the pathogen in saliva. LTA+496C strongly associated with periodontitis, while HLA-DRB1*01 with periodontitis and with the elevated serum antibodies of P. gingivalis. Study IV showed that the increased level of C3/C4 ratio was a new risk factor and was associated with recurrent cardiovascular end-points. The increased C3 and decreased C4 concentrations in serum explained the increased level of the C3/C4 ratio. Both the higher than cut-off value (4.53) and the highest quartile of the C3/C4 ratio were also associated with worst survival, increased end-points, and C4 null alleles. The presence of C4 null alleles associated with decreased serum C4 concentration, and increased C3/C4 ratio. In conclusion, the present studies show that the CAD susceptibility haplotype (HLA-A3− B35− DR1 -related haplotypes, Study I) partially explains the development of CAD in patients possessing several recognized and novel risk factors: diabetes mellitus, increased LDL, smoking, C4B*Q0, C. pneumnoiae, periodontitis, P. gingivalis, and complement C3/C4 ratio (Study II, III, and IV).

Differences in the climatic adaptation of silver birch (Betula pendula) and downy birch (B. pubescens) in Finland based on male flowering phenology.

Male flowering was studied at the canopy level in 10 silver birch (Betula pendula Roth) stands from 8 localities and in 14 downy birch (B. pubescens Ehrh.) stands from 10 localities in Finland from 1963 to 1973. Distributions of cumulative pollen catches were compared to the normal Gaussian distribution. The basis for the timing of flowering was the 50 per cent point of the anthesis-fitted normal distribution. To eliminate effects of background pollen, only the central, normally distributed part of the cumulative distribution was used. Development up to the median point of the distribution was measured and tested in calendar days, in degree days (> 5 °C) and in period units. The count of each parameter began on and included March 19. Male flowering in silver birch occurred from late April to late June depending on latitude, and flowering in downy birch took place from early May to early July. The heat sums needed for male flowering varied in downy birch stands latitudinally but there was practically no latitudinal variation in heat sums needed for silver birch flowering. The amount of male flowering in stands of both birch species were found to have a large annual variation but without any clear periodicity. The between years pollen catch variation in stands of either birch species did not show any significant latitudinal correlation in contrast to Norway spruce stands. The period unit heat sum gave the most accurate forecast of the timing of flowering for 60 per cent of the silver birch stands and for 78.6 per cent of the for downy birch stands. Calendar days, however, gave the best forecast for silver birch in 25 per cent of the cases, while degree days gave the best forecast for downy birch in 21.4 per cent of the cases. Silver birch seems to have a local inclination for a more fixed flowering date compared to downy birch, which could mean a considerable photoperiodic influence on flowering time of silver birch. Silver birch and downy birch had different geographical correlations. Frequent hybridization of birch species occurs more often in northern Finland in than in more southern latitudes. The different timing in flowering caused increasing scatter in flowering times in the north, especially in the case of downy birch. The chance of simultaneous flowering of silver birch and downy birch so increased northwards due to a more variable climate and also higher altitudinal variations. Compared with conifers, the reproduction cycles of both birch species were found to be well protected from damage by frost.

Basic and translational studies on species B adenoviruses

Human adenoviruses (Ads) have been classified into six species (A to F) currently containing 55 serotypes. For almost 2 decades vectors derived from group C serotype Ad5 have been extensively used for gene transfer studies. These Ad5 based vectors are able to efficiently infect many mammalian cell types (including both mitotic and post-mitotic cells) through interaction with a primary attachment receptor, the coxsackie and adenovirus receptor (CAR). Despite the many advantages of Ad5 based vectors a number of limitations have affected their therapeutic application to many diseases. Although they can transduce many tissue types, Ad5 based vectors are unable to efficiently transduce several potential disease target cell types, including hematopoietic stem cells and malignant tumor cells. Therefore, newer vectors have been developed based on Ad serotypes other than Ad5. This thesis focuses on species B Ads. Species B Ads are comprised of three groups based on their receptor usage. Group 1 of species B Ads (Ad16, 21, 35, 50) nearly exclusively utilize CD46 as a receptor; Group 2 (Ad3, Ad7, 14) share a common, unidentified receptor/s, which is not CD46 and which was tentatively named receptor X; Group 3 (Ad11) preferentially interacts with CD46, but also utilizes receptor X if CD46 is blocked. Species B group Ads are important human pathogens. Species B group 2 serotypes are isolated from patients with respiratory tract infections, whereas the Group 1 viruses are described as causing kidney and urinary tract infections. B-group Ad infections often occur in immunocompromised patients, including AIDS patients, recipients of bone marrow transplants, or chemotherapy patients. Recent studies performed in U.S. military training facilities indicate an emergence of diverse species B serotypes at the majority of sites. This included the group 1 serotype 21 and the group 2 serotypes 3, 7, and 14. CD46-targeting vectors derived from Ad35 and Ad11 are important tools for in vitro gene transfer into human stem cells, including hematopoietic stem cells and induced pluripotent stem cells. Ad35 and Ad11 have been used as tools for cancer therapy, because CD46 appears to be uniformely overexpressed on many cancers. Furthermore, receptor X-targeting vectors, i.e vectors derived from Ad3 or vectors containing Ad3 fibers have shown superior in the transduction of tumor cells both in vitro and in vivo and are currently being used clinically in cancer patients. While extensive basic virology studies have been done on Ad5, the information of species B group 1 interaction with CD46 is limited. Furthermore, the receptor for a major subgroup of species B Ads (receptor X) is unknown. The goal of this thesis was it therefore to better understand virological and translational aspects of species B Ads. The specific findings described in this thesis include i) the identification of CD46 binding sites within the Ad35 fiber knob, ii) the study of the in vitro and in vivo properties of Ad vectors with increased affinity to CD46. iii) the study of the receptor usage of a newly emergent Ad14a, iv) the identification of desmoglein 2 as the receptor for Ad3, Ad7, Ad11, and Ad14, v) the delineation of structural details of Ad3 virus interaction with DSG2, and vi) the analysis of functional consequences of Ad3-DSG2 interaction. As a result of these basic virology studies two Ad-derived recombinant proteins have been generated that can be used to enhance cancer therapy by monoclonal antibodies.