Max H. Stickland

RAGE and arthritis: The G82S polymorphism amplifies the inflammatory response

The receptor for advanced glycation end products (RAGE) and its proinflammatory S100/calgranulin ligands are enriched in joints of subjects with rheumatoid arthritis (RA) and amplify the immune/inflammatory response. In a model of inflammatory arthritis, blockade of RAGE in mice immunized and challenged with bovine type II collagen suppressed clinical and histologic evidence of arthritis, in parallel with diminished levels of TNF-alpha, IL-6, and matrix metalloproteinases (MMP) 3, 9 and 13 in affected tissues. Allelic variation within key domains of RAGE may influence these proinflammatory mechanisms, thereby predisposing individuals to heightened inflammatory responses. A polymorphism of the RAGE gene within the ligand-binding domain of the receptor has been identified, consisting of a glycine to serine change at position 82. Cells bearing the RAGE 82S allele displayed enhanced binding and cytokine/MMP generation following ligation by a prototypic S100/calgranulin compared with cells expressing the RAGE 82G allele. In human subjects, a case-control study demonstrated an increased prevalence of the 82S allele in patients with RA compared with control subjects. These data suggest that RAGE 82S upregulates the inflammatory response upon engagement of S100/calgranulins, and, thereby, may contribute to enhanced proinflammatory mechanisms in immune/inflammatory diseases.

Plasminogen Activator Inhibitor-1 Promoter 4G/5G Genotype and Plasma Levels in Relation to a History of Myocardial Infarction in Patients Characterized by Coronary Angiography

To investigate the relationship between an insertion/deletion (4G/5G) polymorphism in the promoter region of the plasminogen activator inhibitor-1 (PAI-1) gene and the phenotypes of PAI-1 levels, coronary atheroma, and a past history of coronary thrombosis, we studied 453 patients (320 men and 133 women) characterized by coronary angiography. Patients were classified as having normal vessels (n = 125) or single-vessel (n = 92) or multivessel (n = 232) coronary disease on the basis of > or = 50% stenosis. PAI-1 antigen levels were highest in patients with the 4G/4G genotype (22.5 ng/mL), with a stepwise decrease in levels as the number of 4G alleles decreased (21.5 ng/mL for 4G/5G and 15.8 ng/mL for 5G/5G, P = .02) after adjusting for age, sex, triglyceride levels, and body mass index (BMI). The association between triglyceride level and PAI-1 was genotype specific, with a steeper slope in subjects with the 4G/4G genotype (P = .004). A gene-environment interaction between BMI, PAI-1, and genotype was observed, with a steeper association in patients with the 5G/5G genotype (P = .02). The 4G/4G genotype was significantly associated with a history of myocardial infarction (P < .03; odds ratio, 2.0; 95% CI, 1.1 to 3.7). This relationship was stronger in subjects with diseased vessels (P = .006). There was no relationship between either PAI-1 genotype or levels and the presence of atheroma. Our data suggest that PAI-1 promoter polymorphism influences the development of myocardial infarction through its effect on thrombus formation in patients with preexisting coronary atheroma.

Factor XIII Val 34 Leu A Novel Association With Primary Intracerebral Hemorrhage

BACKGROUND AND PURPOSE A common G-to-T point mutation (Val 34 Leu) in exon 2 of the alpha-subunit of the factor XIII is strongly negatively associated with the development of myocardial infarction. This result suggests that factor XIII Val 34 Leu is interfering with the formation of cross-linked fibrin. The role of factor XIII Val 34 Leu in the pathogenesis of cerebral infarction and primary intracerebral hemorrhage is unknown. METHODS Six hundred twelve patients with acute stroke, defined by World Health Organization criteria and cranial CT, and 436 age-matched control subjects free of cerebrovascular disease were genotyped for the factor XIII Val 34 Leu mutation. Venous blood was drawn for the determination of hemostatic variables and lipids. Factor XIII genotype was determined through a single-stranded conformational polymorphism technique and plasminogen activator inhibitor (PAI)-1 4G/5G promoter genotype by allele-specific polymerase chain reaction. RESULTS The mutation was more frequent in patients with primary intracerebral hemorrhage (n=62) (54.8%; P=.05) than in control subjects (41.7%) or in patients with cerebral infarction (n=529) (46.5%; P=.22). There was no relationship between PAI-1 levels and the PAI-1 4G/5G genotype. CONCLUSIONS There was a slightly higher incidence of factor XIII Val 34 Leu in patients with PICH. This may be related to impaired cross-linking of fibrin and/or coagulation proteins.

Angiotensin-Converting Enzyme Insertion/Deletion Polymorphism and Cerebrovascular Disease

BACKGROUND AND PURPOSE There is evidence that an allelic variation in the angiotensin-converting enzyme (ACE) gene may confer an increased risk of vascular disease. The roles of the ACE insertion/deletion polymorphism and circulating ACE levels are unknown in cerebrovascular disease. METHODS We studied an insertion/deletion polymorphism within intron 16 of the ACE gene by polymerase chain reaction and plasma ACE activity in 467 cases of stroke, the pathological type of which was established by cranial CT, and 231 control subjects. ACE genotype and activity were related to stroke type and mortality at 4 weeks and 3 months. RESULTS No difference in genotype frequency was observed between all subjects with stroke and control subjects or between control subjects and subjects with cerebral infarction or cerebral hemorrhage. Plasma ACE activity was significantly lower in stroke patients at presentation (64.1 IU/L) than in control subjects (79.6 IU/L; P<.0001). Twenty-one patients (4.5%) with cerebral infarction died within 4 weeks and 56 patients (12%) within 3 months. These patients had significantly lower plasma ACE activity than patients who survived. There was some evidence that risk of death within 4 weeks increased with the number of D alleles (P=.02). Among survivors, plasma ACE activity showed a mean increase of 6.9 IU/L (95% confidence interval, 3.0 to 10.8) between levels at presentation and at 3 months (73.6 IU/L), the latter being similar to ACE activity in control subjects. CONCLUSIONS Low ACE activity at sroke presentation and possession of the D allele may be associated with increased risk of early death from acute cerebral infarction.

The paraoxonase Gln-Arg 192 polymorphism in subjects with ischaemic heart disease.

BackgroundHuman serum paraoxonase activity is related to the paraoxonase Gln-Arg 192 polymorphism genotype. The purpose of this study was to investigate the association between the Gln-Arg 192 polymorphism of paraoxonase and ischaemic heart disease (IHD). MethodsFour hundred and forty patients with a history suggestive of IHD. and characterized by coronary angiography. and 527 healthy controls were studied. Patients were grouped according to paraoxonase genotype, presence or absence of diseased coronary arteries (on the basis of 50% stenosis), and history of myocardial infarction as judged by World Health Organization criteria. Patients were genotyped for the paraoxonase Gln-Arg 192 polymorphism by polymerase chain reaction. ResultsNo significant relationship was found between paraoxonase genotype and age, sex, body mass index, smoking. triglycerides or hypertension However, by one-way analysis of variance, cholesterol was found to be significantly associated with paraoxonase genotype in male patients [AA 5.9 (5.8–6.1), AB 6.2 (6.0–6.4), BB 5.7 (54–6.1); P= 0.04].The Gln-Arg 192 polymorphism was found to have no significant effect on the number of patients having diseased coronary arteries, or having myocardial infarction (P= 0.97 for both). In logistic regression models, paraoxonase genotype did not remain a significant independent predictor of stenosis or myocardial infarction. ConclusionThis study failed to show an association between the Gln-Arg 192 polymorphism of paraoxonase and the clinical phenotypes of coronary atheroma and acute myocardial infarction.

β-fibrinogen gene −455 G/A Polymorphism and Fibrinogen Levels: Risk factors for coronary artery disease in subjects with NIDDM

OBJECTIVE To investigate the association of a G/A polymorphism at position −455 of the β-fibrinogen gene and fibrinogen levels in the development of coronary artery disease (CAD) in subjects with NIDDM. RESEARCH DESIGN AND METHODS In 187 Caucasian subjects with NIDDM, presence of CAD was taken as a clinical history of angina, myocardial infarction, coronary angioplasty, or coronary artery bypass grafting, confirmed from medical case notes. RESULTS Fibrinogen levels were significantly higher in subjects with CAD (n = 38, 3.41 [3.12–3.73] g/l) than those without (n = 149, 2.99 [2.87–3.11] g/l, P = 0.004 [geometric mean, 95% CI]). Comparing the genotype frequencies by X2 testing, there was a significant difference between subjects with CAD (GG = 0.84, GA + AA = 0.16) and those without (GG = 0.64, GA + AA = 0.36, P = 0.02). In a logistic regression model, including age, BMI, cholesterol, sex, smoking, triglycerides, and plasminogen activator inhibitor antigen as covariates, genotype and fibrinogen levels were significantly associated with CAD. The odds ratio for having CAD in individuals homozygous for the G allele compared with those possessing the A allele was 1.77 (1.08−2.90), P = 0.03; and for an increase of 1 g/l in fibrinogen levels was 1.60 (1.00–2.60), P = 0.05. CONCLUSIONS These data suggest a relationship between the −455 G/A β-fibrinogen gene polymorphism and the development of CAD in subjects with NIDDM. This relationship was not associated with variations in fibrinogen levels, suggesting that this polymorphism may be in linkage with a polymorphism within the coding region of the β-fibrinogen gene, which results in an alteration in the stability of the fibrin clot.

Promoter (4G/5G) plasminogen activator inhibitor-1 genotype in Pima Indians: relationship to plasminogen activator inhibitor-1 levels and features of the insulin resistance syndrome

Summary Elevated plasminogen activator inhibitor-1 may contribute to vascular disease in diabetes mellitus. Pima Indians have a low incidence of cardiovascular disease despite having a high prevalence of non-insulin-dependent diabetes mellitus (NIDDM) which in this population is not associated with elevated plasminogen activator inhibitor-1 activity. In Caucasians an insertion/deletion (4G/5G) polymorphism in the promoter region of the plasminogen activator inhibitor-1 gene that has been related to activity levels of its protein in plasma differentially binds repressor and enhancer elements. In 265 Pima Indians (133 diabetic, 132 non-diabetic, 129 male, 136 female, mean age 46.6, range 34–68 years) the promoter genotype frequencies were 23.0 % for 4G/4G, 49.8 % for 4G/5G and 27.2 % for 5G/5G compared to 35.4 %, 50.8 % and 13.8 % respectively (χ2 = 15.3, 2 df, p < 0.0005) previously reported in Caucasians with NIDDM. The mean plasma activity levels in the three genotypes in the Pima Indians were 18.2, 19.1 and 18.1 U/ml, respectively. Plasminogen activator inhibitor-1 activities correlated with plasma insulin (r = 0.38, p < 0.0001), body mass index (r = 0.24, p < 0.0001), and with triglyceride level (r = 0.12, p = 0.054) but there was no relationship between promoter genotype and activity. A steeper regression slope between plasminogen activator inhibitor-1 activity and triglycerides has been observed in Caucasians with the 4G/4G genotype as compared to Caucasians with the other genotypes. This was not found in the Pima population which may indicate a functional difference in this gene associated with reduced cardiovascular risk and may be involved in the lack of association of plasminogen activator inhibitor-1 levels with NIDDM in Pima Indians. [Diabetologia (1996) 39: 1512–1518]

The Effect of Number of Days in Culture and Plasminogen Activator Inhibitor-1 (PAI-1) 4G/5G Genotype on PAI-1 Antigen Release by Cultured Human Umbilical Vein Endothelial Cells

An insertion/deletion (4G/5G) polymorphism in what has been shown to be an enhancer/repressor binding site in the promoter region of the PAI-1 gene has been related to plasma PAI-1 activity. Transfection studies demonstrated increased interleukin-1 stimulated PAI-1 synthesis in cells containing the 4G sequence. To study this response in endothelial cells, first passage HUVEC from 26 umbilical cords were stimulated with interleukin-1 and tumor necrosis factor-alpha. PAI-1 antigen was measured in 24-hour conditioned medium and allele-specific PCR utilized to determine genotype at the 4G/5G locus. Analysis of covariance was used to determine whether the effect of a variable time in culture was masking a difference between genotypes. A trend towards higher PAI-1 levels with increasing time in culture was observed. The geometric mean (95% confidence interval) of the basal rate of PAI-1 release was, 4G/4G 9.7 (7.0, 13.5) ng/24 hours (n=11), 4G/5G 9.5 (6.5, 13.9) ng/24 hours (n=9), and 5G/5G 10.9 (7.8, 15.1) ng/24 hours (n=6). In cells of the same cultures, the interleukin-1 stimulated levels were 25.9 (23.1, 29.1), 27.2 (23.6, 31.3), and 23.1 (19.5, 27.3) ng/24 hours, respectively, corresponding to ratios of stimulated to basal levels of 2.68, 2.87, and 2.12. After adjustment for time in culture the basal PAI-1 release was 4G/4G 10.7, 4G/5G 9.1, and 5G/5G 9.7 ng/24 hours. For interleukin-1 stimulated release the adjusted levels were 26.3, 27.0, and 22.7 ng/24 hours, respectively. Adjusted levels in 4G/4G genotype cells were non-significantly greater than those in cells of 5G/5G genotype by a factor of 1.16 (0.95, 4.08). This study did not demonstrate a significant difference in basal or cytokine stimulated PAI-1 release from cells of different PAI-1 promoter (4G/5G) genotypes but does not exclude increased interleukin-1 stimulated PAI-1 release in the 4G/4G compared with the 5G/5G genotype.

Effect of controlled hyperglycaemia on factor VIII concentrations in insulin dependent diabetes mellitus.

Patients with diabetes mellitus have higher levels of coagulation factor VIII than the non-diabetic population. This may be a result of poor metabolic control and could contribute to the development of microvascular complications. During ketoacidosis there are acute changes in plasma concentrations of coagulation factors, some of which may be mediated by the rise in vasopressin that occurs. We have investigated the effects of hyperglycaemia without ketosis on some aspects of haemostasis by manipulating blood glucose concentrations using a Biostator. After a 1h run-in period with the blood glucose at 5 mmol/l, the blood glucose was maintained at 5, 15 and 25 mmol/l and maintained for one hour at each level in six male patients with insulin-dependent diabetes. Insulin was infused at 0.25 mu/kg/min. Venous blood samples were taken at the beginning and end of each hour after the run-in period for assays of factor VIII coagulant activity (FVIII:C), von Willebrand factor antigen (vWF:Ag), ristocetin co-factor (FVIIIR:Co), activated partial thromboplastin time (APTT) and vasopressin (aVP). There was a slight, though statistically insignificant fall in median factor VIII:C concentration at each incremental level of increase in blood glucose. Values (at the beginning and end of each hour) were: 1.0 and 1.1 iu/ml at 5 mmol/l; 0.95 and 0.79 iu/ml at 15 mmol/l; and 0.74 and 0.84 iu/ml at 25 mmol. vWF:Ag and FVIIIR:Co were unchanged. Plasma aVP fell slightly from 1.1 to 0.5 pg/ml. The results indicate that high levels of FVIII seen in diabetes are not due to short-term increases in blood glucose and that acute hyperglycaemia does not promote pro-coagulant changes in blood.