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Biomedical subjects

T Lehtimäki

Publications and source records attributed to T Lehtimäki.

At least 19 recordsLinked to original sources
PubMed2007

Autoimmunity and atherosclerosis: functional polymorphism of PTPN22 is associated with phenotypes related to the risk of atherosclerosis. The Cardiovascular Risk in Young Finns Study.

There is a growing body of evidence attesting the significance of inflammation in the pathogenesis of atherosclerosis. Protein tyrosine phosphate PTPN22 C/T single nucleotide polymorphism (SNP) at + 1858 has been identified recently as a susceptibility factor for various inflammatory autoimmune diseases. We hypothesized that data on the genetic polymorphism of the PTPN22 enzyme associated with an increased risk of autoimmunity could also provide insight into the possible role of autoimmunity in the pathogenesis of atherosclerosis. Therefore we analysed the PTPN22 + 1858 C/T polymorphism in a population of young Finnish adults (n = 2268) for whom data on carotid artery intima-media thickness (IMT), a presymptomatic predictor of atherosclerosis, and risk factors for atherosclerosis were available. In males carriage of the T allele of PTPN22 + 1858 was associated significantly with IMT in univariate and multivariate analyses, while in females it was associated with several risk factors for atherosclerosis (BMI, waist circumference, waist-to-hip ratio, serum concentrations of C-reactive protein and triglycerides) but not with IMT. Our results indicate that the genetic polymorphism of PTPN22 + 1858 known to predispose to autoimmunity also enhances the development of atherosclerosis and thereby links the genetics of autoimmunity and atherosclerosis.

Adult↗
PubMed2006

Interaction between TPH1 and GNB3 genotypes and electroconvulsive therapy in major depression.

We studied the association between tryptophan hydroxylase 1 (TPH1) A218C and G-protein beta-3 subunit (GNB3) C825T polymorphisms and treatment response in electroconvulsive therapy (ECT). The sample consisted of 119 patients with major depressive disorder (MDD) and 398 controls. Neither TPH1 nor GNB3 polymorphisms are associated with treatment response. However, subjects carrying TPH1 CC genotype are more likely to belong to the patient sample than to the controls. In female subjects, T-allele of GNB3 polymorphism increases the risk of being a treatment-resistant patient with MDD. Moreover, in females the combination of TPH1 CC and GNB3 CT + TT genotype is associated with an increased risk of belonging to the patient group.

Major Depressive Disorder↗
PubMed2006

RGS4 genotype is not associated with antipsychotic medication response in schizophrenia.

The aims of the present study were to compare the allele frequencies of a common single nucleotide polymorphism located upstream of the regulator of G-protein signaling 4 (RGS4) gene (T > G, Rs 951436) in 219 Finnish patients with schizophrenia and in 389 control subjects, to analyze corresponding frequencies between two different subtypes of 93 schizophrenia patients according to their medication response, and to study the effect of this SNP on age at onset in schizophrenia. The RGS4 (T > G, Rs 951436) genotype was not associated with incidence or age at onset in schizophrenia. Neither was the RGS4 genotype associated with medication response with two different subpopulations with schizophrenia.

Adult↗
PubMed2006

Indoleamine 2,3-dioxygenase activity in nonagenarians is markedly increased and predicts mortality.

Indoleamine 2,3-dioxygenase (IDO), an enzyme degrading tryptophan (trp) to kynurenine (kyn), suppresses T cell activity. Ageing of the immune system, immunosenescence, includes a decline in T cell function. We therefore sought to establish whether IDO activity is involved in immunosenescence and whether it predicts mortality in aged subjects. We measured kyn/trp, reflecting IDO activity, in 284 nonagenarians and 309 blood donor controls. IDO activity was significantly higher in nonagenarians compared with controls and IDO activity at study entry predicted subsequent mortality in nonagenarians. Thus, increased IDO activity might be a mechanism involved in the decline of T cell responses in immunosenescence.

Adult↗
PubMed2006

Serum matrix metalloproteinase-9 and venous bypass graft occlusion.

OBJECTIVE: The primary results after coronary artery bypass grafting are good, but early clinical events as a result of graft occlusion are still a problem. Early occlusions are thought to be due to thrombosis or fibrointimal hyperplasia superimposed by thrombosis, but the etiology of these phenomena is not fully understood. Matrix metalloproteinase-9 has been suggested to have a role in graft occlusion ex vivo. MATERIAL AND METHODS: We investigated whether the level of serum matrix metalloproteinase-9 reflects its proposed role in occlusion of vein grafts. The study population consisted of 30 men with a history of myocardial infarction and 31 men without myocardial infarction who had undergone coronary artery bypass grafting. All the men were asymptomatic. RESULTS: Among the patients with no previous myocardial infarction, serum matrix metalloproteinase-9 level was significantly higher in those with graft occlusion than in those without occlusion (54.0+/-11.0 microg/L and 41.7+/-10.4 microg/L, respectively, p = 0.006), and it correlated positively with the number of occluded grafts (R = 0.55, p = 0.001). In the patients with myocardial infarction, this effect was not detected. CONCLUSIONS: Serum matrix metalloproteinase-9 reflected the occurrence of vein graft occlusion in subjects with no previous history of myocardial infarction.

Aged↗
PubMed2006

Relation of myeloperoxidase promoter polymorphism and long-term hormone replacement therapy to oxidized low-density lipoprotein autoantibodies in postmenopausal women.

OBJECTIVE: The myeloperoxidase enzyme (MPO) is a potent precursor of low-density lipoprotein (LDL) oxidation in atherosclerotic lesions. The MPO gene has a promoter polymorphism, 463G/A, which leads to high (GG) and low-expression (AG, AA) genotypes. Hormone replacement therapy (HRT) is known to affect MPO activity and LDL oxidation. The purpose of this study was to test whether the effect of HRT on the levels of oxLDL-ab varies according to MPO genotype. MATERIAL AND METHODS: Eighty-seven postmenopausal women aged 45-71 years were divided into three groups based on the use of HRT. The HRT-EVP group (n = 25) used sequential estradiol valerate (EV) plus progestin, the HRT-EV group (n = 32) used EV alone, and the control group (n = 30) no HRT. MPO genotypes were determined by polymerase chain reaction (PCR) and oxLDL-ab by ELISA. RESULTS: We found a significant HRT group by MPO genotype interaction (p = 0.021) in plasma oxLDL-ab levels. In subjects with the GG genotype, the oxLDL-ab titer increased in the order of 2.13 in controls, 2.53 in the EV group and 3.21 in the EVP group (ANOVA for trend p = 0.006). CONCLUSIONS: The effects of HRT on LDL oxidation can vary according to MPO genotype and the concurrent progestin therapy with EV may counteract the more neutral effect of EV on LDL oxidation in subjects with the MPO high-expression genotype.

Aged↗
PubMed2006

Effects of oxidized low- and high-density lipoproteins on gene expression of human macrophages.

OBJECTIVE: Oxidized low-density lipoprotein (ox-LDL) is a major factor in foam cell formation, whereas the role of oxidized high-density lipoprotein (ox-HDL) in this process is not known. The objective of the present study was to examine the effects of ox-LDL and ox-HDL on the gene expression of cultured human macrophages. MATERIAL AND METHODS: Gene expression of human macrophages was studied after incubation for 1 day and 3 days with native and oxidized LDL and HDL using cDNA expression array. Expression of granulocyte-macrophage colony-stimulating factor 1, which was constantly up-regulated by ox-LDL and down-regulated by ox-HDL after 1- and 3 days of incubation in cDNA microarray experiments, was verified by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: Genes that showed altered expression were divided into six groups; 1) lipid metabolism, 2) inflammation, growth and hemostasis, 3) matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases, 4) enzymes, 5) structural and binding proteins and 6) annexins. CONCLUSIONS: The microarray method was found to be applicable in analyzing changes in gene expression induced by oxidized lipoproteins in cultured human macrophages. Our results reflect different functional roles of ox-LDL and ox-HDL in foam cell formation.

Base Sequence↗
PubMed2006

Toll-like receptor 4 polymorphism is associated with coronary stenosis but not with the occurrence of acute or old myocardial infarctions.

OBJECTIVE: Atherosclerosis is considered to be a chronic inflammatory disease. Toll-like receptor 4 (TLR-4), a key mediator in activating inflammatory cascade, has an A-to-G functional polymorphism that changes aspartic acid to glycine at position 299. TLR-4 is activated by, for example, lipopolysaccharides. The purpose of this study was to investigate the role of a common Asp299Gly polymorphism of the TLR-4 gene in atherosclerosis. MATERIAL AND METHODS: The study comprised autopsy material from 657 men (the Helsinki Sudden Death Study; mean age 53, range 33-70 years). RESULTS: Fewer G-allele carriers had 3-vessel coronary artery disease compared with AA homozygotes (OR 0.32; 95 % CI, 0.12-0.88, p = 0.027), and they also had a lower mean value for maximal coronary stenosis (p = 0.019). TLR-4 polymorphism was not significantly associated with the occurrence of acute or old myocardial infarction (MI). CONCLUSIONS: The G allele of the TLR-4 gene, which is associated with a lower inflammation response, was associated with a lower risk of coronary stenosis but not with the occurrence of MI and hence is not a major factor in the development of coronary atherosclerosis.

Acute Disease↗
PubMed2006

Effect of high-dose methylprednisolone treatment on CCR5 expression on blood cells in MS exacerbation.

OBJECTIVES: Therapy of acute exacerbations of multiple sclerosis (MS) with high-dose intravenous methylprednisolone (IVMP) has shortened the recovery period after relapses, but the mechanisms responsible for the beneficial effects of IVMP in attacks have not been clearly established. Our purpose was to analyze the effect of IVMP on the expression of chemokine receptor 5 (CCR5) protein in blood in acute MS exacerbation. MATERIALS AND METHODS: Blood samples were collected from 10 patients with an acute MS exacerbation and the levels of CCR5 on CD4(+) and CD8(+) T cells and CD14(+) monocytes were analyzed by using flow cytometry before IVMP, 24 h, 1 and 3 weeks after commencement of treatment. RESULTS: During the 3-week period the percentages of CCR5-expressing CD4(+) T cells and CD8(+) T cells tended to decrease (P = 0.09 and 0.05, respectively), but the effect did not reach statistical significance. No marked changes were found in the percentage of CCR5-expressing CD14(+) cells. CONCLUSIONS: A tendency to a reduction of CCR5-expressing CD4(+) and CD8(+) blood cells induced by IVMP suggests inhibition of their potential to transmigrate into the central nervous system, which is consistent with the short-term beneficial effect of IVMP in acute exacerbation of MS.

Adult↗
PubMed2006

Cloninger's temperament dimensions and epidermal growth factor A61G polymorphism in Finnish adults.

This study examines a link between human temperament and epidermal growth factor (EGF). There is evidence that dopaminergic neurotransmission in the central nervous system has a role in temperament, especially in novelty seeking. Functional polymorphism in EGF gene has an impact on EGF production, and EGF, in turn, appears to affect the development of midbrain dopaminergic neurons. Epidermal growth factor gene A61G polymorphisms were studied in a randomly selected sample of 292 Finnish adults. Their temperaments were assessed twice (with a 4-year test-retest interval) with Cloninger's Temperament and Character Inventory consisting of four dimensions, i.e. novelty seeking (NS), harm avoidance (HA), reward dependence (RD) and persistence (P). The findings on men showed a significant association between a presence of the G/G polymorphism and scoring in the highest tertile on NS in both test and retest. The same was true with men who scored high on RD, especially on sensitivity, in both tests. Among women, G/G polymorphism was associated with a stable high level of P. Importantly, temperament dimensions, as assessed with one test only, did not provide replicable associations with EGF polymorphism across the two measurements. Our results demonstrate the importance of reliable phenotype assessment and lend support to the hypothesis that dopaminergic activity is one factor underlying stable temperament.

Adult↗
PubMed2005

HDL enhances oxidation of LDL in vitro in both men and women.

BACKGROUND: Oxidative modification of low-density lipoprotein (LDL) is a key event in the oxidation hypothesis of atherogenesis. Some in vitro experiments have previously suggested that high-density lipoprotein (HDL) co-incubated with LDL prevents Cu2+-induced oxidation of LDL, while some other studies have observed an opposite effect. To comprehensively clarify the role of HDL in this context, we isolated LDL, HDL2 and HDL3 from sera of 61 free-living individuals (33 women and 28 men). RESULTS: When the isolated LDL was subjected to Cu2+-induced oxidation, both HDL2 and HDL3 particles increased the rate of appearance and the final concentration of conjugated dienes similarly in both genders. Oxidation rate was positively associated with polyunsaturated fatty acid content of the lipoproteins in that it was positively related to the content of linoleate and negatively related to oleate. More saturated fats thus protected the lipoproteins from damage. CONCLUSION: We conclude that in vitro HDL does not protect LDL from oxidation, but is in fact oxidized fastest of all lipoproteins due to its fatty acid composition, which is oxidation promoting.

Adult↗
PubMed2005

Interleukin-6 -174G/C polymorphism and longevity: a follow-up study.

Increased rate of inflammation has been observed to be associated with aging. This is manifested, e.g. as increased blood levels of proinflammatory cytokines, such as interleukin-6 (IL-6). The production of IL-6 is, at least partially, genetically determined the single nucleotide polymorphism (SNP) at the promoter (-174G/C) being decisive. Consequently, some studies have demonstrated that the -174G/C genotype frequencies are different in very old persons as compared to younger ones. However, the results published this far have been conflicting. One of the main confounding factors in these kind of case/control association studies is the undetected difference in the population structure. To avoid this, we now have collected the mortality data of our cohort of 285 nonagenarians (representing mortality between 90 and 95 years of age) and correlated these to the IL-6 genotype. The frequency of -174 allele G was clearly higher in the survivors (n = 114) than in the non-survivors (n = 171).

Aged↗
PubMed2005

Epistatic effect of C-reactive protein (CRP) single nucleotide polymorphism (SNP) +1059 and interleukin-1B SNP +3954 on CRP concentration in healthy male blood donors.

Baseline C-reactive protein (CRP) concentrations are indicative of persons prone to cardiovascular diseases and are about 40-50% heritable. We have previously shown that interleukin (IL)-1B +3954 allele T is associated with lower CRP concentration. In this study, we aimed to examine the effect of this polymorphism together with the CRP +1059 gene polymorphism on baseline CRP concentrations, and genotyped 336 healthy blood donors for CRP +1059 (G-->C) and IL-1B +3954 (C-->T) polymorphisms. In men, the carriers of the CRP +1059 C-allele had significantly lower CRP values than GG homozygotes (0.66 versus 0.43 mg l(-1), up to -35%, P = 0.009). No significant difference was found in women. When the data were stratified for both of these polymorphisms in men, CRP +1059 GG homozygotes had low CRP concentrations only if they were allele-T carriers of IL-1B +3954 simultaneously (0.93 versus 0.50 mg l(-1), P = 0.013). Genotype CRP +1059 GG/IL-1B +3954 CC was associated with an almost 3-fold risk of a higher baseline CRP value [odds ratio (OR) 2.84 (CI 1.03-6.07)]. Thus, both IL-1B +3954 (C-->T) and CRP +1059 (G-->C) polymorphisms influence baseline CRP values and act independently of each other in male subjects. These polymorphisms might be predictive markers of persons prone to cardiovascular diseases.

Blood Donors↗
PubMed2004

Lack of association between two polymorphisms of brain-derived neurotrophic factor and response to typical neuroleptics.

Several studies have connected brain-derived neurotrophic factor (BDNF) with treatment response to neuroleptics. In recent studies, the BDNF expression was reduced by typical neuroleptics. We conducted a retrospective study on 94 patients with schizophrenia and 98 controls. The BDNF G196A and C270T polymorphisms are not associated with treatment response to typical neuroleptics or with age at first hospitalization. Moreover, these polymorphisms of the BDNF gene are not associated with the risk of schizophrenia.

Age of Onset↗
PubMed2004

Presence of apolipoprotein E epsilon4 allele predisposes to early onset of primary Sjogren's syndrome.

BACKGROUND: Apolipoprotein E (apoE) polymorphism plays a central role in lipid metabolism, but has recently also been suggested to regulate inflammation, as judged by levels of serum C-reactive protein (CRP). OBJECTIVE: To establish whether polymorphism of the apoE genes affects susceptibility to primary Sjogren's syndrome (pSS), degree of inflammation or age of onset of pSS. METHODS: ApoE genotype distribution and allelic frequencies were analysed using PCR and the TaqMan system in 63 Finnish Caucasian patients with pSS and in 64 healthy controls matched for sex, ethnic origin and area of residence. The clinical and immunological data on the pSS patients were analysed in relation to the apoE genotypes. RESULTS: There was no difference between pSS patients and controls in apoE genotype and allelic frequencies. The apoE epsilon4 allele was significantly associated with early onset of pSS in the entire population and in female patients (Kaplan-Meier log rank test, P = 0.0407 and P = 0.0168, respectively). The average age (+/- S.D.) of onset of pSS in all apoE epsilon4 allele carriers was 46 +/- 12 and in other genotypes it was 53 +/- 10 yr (P = 0.031, t-test). ApoE polymorphism was not associated with signs of inflammation evaluated by such markers as concentration of plasma CRP, plasma interleukin-6, plasma TNF-alpha, immunoglobulin G and haemoglobin, or leucocyte count or ESR. CONCLUSIONS: ApoE polymorphism does not affect susceptibility to pSS or levels of plasma inflammatory indices in patients with pSS. However, a clear association prevails between apoE epsilon4 and early onset of pSS.

Age of Onset↗
PubMed2004

Matrix metalloproteinase 9 (MMP-9) gene polymorphism and MMP-9 plasma levels in primary Sjogren's syndrome.

OBJECTIVES: To determine whether plasma matrix metalloproteinase 9 (MMP-9) and MMP9 (-1562C-->T) polymorphism have an effect on the disease phenotype in primary Sjogren's syndrome (pSS). METHODS: Plasma MMP-9 concentrations and polymorphism of the MMP9 gene were analysed in 66 patients with pSS. These data were studied in relation to the clinical data of the patients. The genetic data of patients were compared with the data of 66 healthy subjects. RESULTS: Plasma MMP-9 was higher in patients with definite pSS than in patients with possible pSS. This association was principally caused by higher plasma MMP-9 in patients with a positive Schirmer test and keratoconjunctivitis sicca. pSS patients with purpura, SS-A autoantibodies and RF had significantly lower plasma MMP-9 than patients without these characteristics. The overall MMP9 (-1562C-->T) allele frequencies were similar in patients and control subjects. The frequency of the allele T was higher in patients without Raynaud's phenomenon than in the control group. CONCLUSIONS: MMP9 (-1562C-->T) could not be used for risk assessment in pSS. The presence of the rarer allele T may decrease the risk of Raynaud's phenomenon in pSS. High plasma MMP-9 is indicative of definite pSS but may paradoxically have a preventive effect on the eruption of purpura and on the development of autoantibody reaction in pSS.

Aged↗
PubMed2004

Increase in CCR5 Delta32/Delta32 genotype in multiple sclerosis.

Chemokines and their receptors participate in the development of multiple sclerosis (MS) by guiding immune cells into the brain tissue. A CCR5 Delta32 deletion mutation abolishes functional CCR5 on the cell surface and may reduce cell entry into the lesion sites. To analyse the significance of this mutation in MS, we compared the frequencies of CCR5 genotype in peripheral blood mononuclear cells from 89 MS patients and 119 healthy controls. The CCR5 genotype was further compared with the CCR5 RNA and surface protein expression in 48 MS patients and their controls. In all MS patients, the Delta32/32 genotype was found with 6.7% frequency, whereas it was present only in 0.8% of the controls (6/89 vs 1/119, P = 0.01). Specifically, the Delta32/Delta32 genotype was increased (11.5%, P = 0.05) among primary progressive MS patients, whereas it was present only in 4.8% in other MS subtypes and only in 0.8% of the controls. The amount of CCR5 protein on CD4(+) cells analysed in 48 MS patients (nine primary progressive MS, 18 secondary progressive MS, 21 relapsing-remitting MS) and 13 controls decreased with genotype, being 8.9% in wt/wt, 7.7% in wt/Delta32 and 4.3% in Delta32/Delta32. CCR5 surface expression analysed on these 48 MS patients and 13 controls was significantly decreased in Delta32/Delta32 MS patients as compared with that in wt/wt genotype individuals (P = 0.004). The significantly increased number of Delta32/Delta32 individuals among our MS patients suggests that this genotype could contribute as a general risk factor for MS. However, neither the levels of RNA or surface protein correlated with MS subtype, neurological disability as expressed by expanded disability status scale, or disease progression index. Our results suggest that the lack of CCR5 does not protect from MS, but rather it may predispose to the chronic course of the disease. This would further imply that in view of the redundancy in the chemokine system, CCR5 ligands must be assumed to function through other closely related chemokine receptors.

Adult↗