Impact of C-reactive protein on the likelihood of carotid atherosclerosis in Japanese adults

OBJECTIVE

Several cohort studies have shown a link between serum C-reactive protein (CRP) and subsequent cardiovascular disease; however, the role of CRP as an independent risk factor remains controversial. We therefore investigated the association between CRP and sclerotic lesions of common carotid atherosclerosis.

PATIENTS AND METHODS

We evaluated sclerotic lesions of common carotid arterial intima-media thickness (IMT) by ultrasonography in 139 men aged 67 +/- 15 years and 201 women aged 75 +/- 10 years. To investigate the relation between CRP and various confounding factors, subjects were divided into four groups based on the quartile of CPR.

RESULTS

Carotid IMT values were significantly higher in groups with higher CRP (p = 0.022). To identify the possible CRP level and risk factor interactions for IMT, multiple regression analysis for IMT was performed based on risk factors in subjects with a specific CRP level. It was shown that age, smoking status, systolic blood pressure (SBP) and LDL cholesterol were significantly associated with IMT in subjects in the lower CRP groups (CRP-1 approximately CRP-3), and age, SBP and presence of diabetes mellitus in the highest CRP group (CRP-4). To further investigate whether the interaction between CRP and conventional risk factors could influence IMT, a general linear model demonstrated that interaction between CRP and the presence of diabetes mellitus (F = 4.754 p = 0.030) was significantly associated with IMT, in addition to sex, age, SBP, antihypertensive drug use, LDL cholesterol and HDL cholesterol.

CONCLUSIONS

This finding indicates that the association between CRP and IMT significantly differed between subjects with and without diabetes mellitus.

Metabolic Syndrome, Diabetes and Subclinical Atherosclerosis as Assessed by Carotid Intima-Media Thickness

AIM

Carotid intima-media thickness (IMT) is a useful surrogate marker of cardiovascular disease and is associated with cardiac events. We investigated cross-sectionally the association between carotid intima-media thickness (IMT), confounding risk factors, and metabolic syndrome (MetS) using the modified Japanese criteria.

METHODS

Carotid IMT was evaluated on B-mode ultrasonography in 918 patients (394 men aged 66 +/- 15 years and 524 women aged 72 +/- 13 years).

RESULTS

Among our 918 patients, 74 (8.1%) had no metabolic abnormalities, 478 (52.1%) had a metabolic abnormality with neither type 2 diabetes or MetS, and 127 had MetS without diabetes. Of the patients with type 2 diabetes, 132 (14.4%) did not have MetS and 107 (11.7%) had both type 2 diabetes and MetS. The carotid IMT values in the four groups with any metabolic abnormalities were significantly greater than the IMT of the group with neither condition (p=0.001), respectively. In syndrome model, type 2 diabetes was significantly associated with carotid atherosclerosis (p= 0.006), but MetS was borderline significant. In the component model of MetS, there was a significant association with hypertension (p<0.001) and dyslipidemia (p=0.006). Multiple logistic regression analysis for carotid atherosclerosis compared to neither condition demonstrated that subjects with both MetS and diabetes (OR, 5.58; 95% CI, 2.64-11.8), those with type 2 diabetes without MetS (OR, 3.00; 95% CI, 1.45-6.22), and those with MetS without type 2 diabetes (OR, 2.58; 75% CI, 1.24-5.39) showed a higher odds ratio after adjustment for covariates.

CONCLUSION

Even after taking into account each individual component of MetS, the clustering of visceral obesity with at least 2 of the 3 components, and diabetes are independently associated with increased carotid IMT. This suggests that the components of MetS and type 2 diabetes interact to affect vascular thickness synergistically.

Metabolic Syndrome may be a Risk Factor for Early Carotid Atherosclerosis in Women but not in Men

AIM

Metabolic syndrome (MetS) is a cluster of metabolic abnormalities and a predictor of both type 2 diabetes mellitus and adverse cardiovascular events. Whether there are gender differences in the association between early atherosclerosis and MetS has not yet been thoroughly elucidated.

METHODS

The subjects consisted of 388 men aged 64+/-16 years and 480 women aged 70+/-13 years. Early atherosclerosis was assessed by carotid intima-media thickness (IMT) on B-mode ultrasonography.

RESULTS

Carotid IMT values were significantly greater in both male (p=0.007) and female (p=0.002) subjects with MetS. After adjusting for established risk factors, the difference persisted on a significant level in women (p=0.003), but was weak in men (p=0.013). Multiple regression analysis using IMT as an objective variable, with adjustment for various risk factors as explanatory variables, showed that MetS (p=0.016) was a significant independent contributing factor along with known risk factors only in women. Among the components of MetS, hypertension (p=0.036) and dyslipidemia (p=0.008) had a strong impact on carotid IMT in men, whereas hypertension (p=0.003) ranked first in women.

CONCLUSION

The effect of MetS in early carotid atherosclerosis is more pronounced in women than in men, and the impact of MetS components on carotid IMT differs between men and women.

Metabolic syndrome amplifies the LDL-cholesterol associated increases in carotid atherosclerosis

OBJECTIVE

Carotid intima-media thickness (IMT) is a useful surrogate marker of cardiovascular disease. In addition to low-density lipoprotein cholesterol (LDL-C), metabolic syndrome has been linked to the pathogenesis of atherosclerosis. The present study investigated whether the clustering of multiple components of metabolic syndrome has a greater impact on vascular parameters than individual components of metabolic syndrome, and assessed the association between carotid IMT and LDL-C and metabolic syndrome.

METHODS

Carotid IMT was evaluated on B-mode ultrasonography in 760 patients (340 men aged 64+/-16 years and 420 women aged 69+/-13 years) in the Medical Department of Seiyo Municipal Nomura Hospital. The subjects did not demonstrate any clinical signs of cardiovascular disease. We investigated the association between carotid IMT and confounding risk factors including LDL-C and metabolic syndrome using the 2005 Japanese criteria.

RESULTS

Carotid IMT increased with increasing numbers of metabolic syndrome components (p for trend<0.001). Multiple regression models, including age, sex, body mass index, smoking status, LDL-C, diabetes mellitus as well as each individual component of metabolic syndrome as continuous variables, showed that both metabolic syndrome (beta=0.100; p=0.029) and LDL-C (beta=0.210, p<0.001) were independent determinants of carotid IMT. Metabolic syndrome amplified the LDL-C associated increases in carotid atherosclerosis.

CONCLUSIONS

Even after taking into account each individual component of MS, the clustering of visceral obesity with at least 2 of the 3 components, and LDL-C are independently associated with increased carotid IMT. This suggests that the components of metabolic syndrome interact to synergistically impact vascular thickness.

Association between uric acid and carotid atherosclerosis in elderly persons

OBJECTIVE

Several cohort studies have shown a link between serum uric acid (SUA) and subsequent cardiovascular disease. However, such an association did not remain significant after adjusting for concomitant risk factors for atherosclerosis in some studies. Thus, the role of SUA as an independent risk factor remains controversial. We therefore investigated the association between SUA and sclerotic lesions of common carotid atherosclerosis.

PATIENTS AND METHODS

We evaluated sclerotic lesions of the common carotid arterial intima-media thickness (IMT) by ultrasonography in 398 men aged 74+/-8 (range, 60-97) years and 521 women aged 75+/-8 (range, 60-104) years. To investigate the relation between SUA and various factors, all subjects were divided into three groups based on the tertile of SUA.

RESULTS

Stepwise multiple linear regression analysis using IMT as an objective variable, adjusted by various risk factors as explanatory variables showed that SUA [B, 0.0099; 95% confidence interval (CI), 0.0022-0.0175] was a significant independent contributing factor along with known risk factors such as age, sex, smoking status, systolic blood pressure, diastolic blood pressure, antihypertensive drug use, HDL-cholesterol, and LDL-cholesterol. Multiple logistic regression analysis for carotid IMT as a tertile of SUA and dependent variables showed that the adjusted odds ratio was 1.25 (95% CI, 0.87-1.78) for those in the middle tertile (4.2-5.5 mg/dl), and 1.66 (95% CI, 1.16-2.39) for those in the highest tertile (5.6-14.1 mg/dl) compared to that for subjects in the lowest tertile of SUA levels (0.51-4.1 mg/dl).

CONCLUSION

We suggest that SUA is a risk factor or marker for ultrasonographically determined IMT.

Metabolic Syndrome and Carotid Atherosclerosis: Role of Elevated Blood Pressure

It is not known whether subjects with metabolic syndrome and elevated blood pressure are at the same cardiovascular risk as subjects with metabolic syndrome but without elevated blood pressure. Using B-mode ultrasonography, carotid IMT was measured in 1,297 patients (593 men and 704 women) in the medical department of Seiyo Municipal Nomura Hospital between August 1996 and April 2005. The prevalence of metabolic syndrome was 32.5% among men and 35.9% among women. On comparing subjects with an equal number of components of metabolic syndrome, it was found that the prevalence of carotid atherosclerosis was significantly higher in subjects with elevated blood pressure than in those without, and increased with the number of components in the former group (p for trend = 0.0277), but not in the latter (p for trend = 0.5159). In a stepwise multiple logistic regression analysis, after adjustment for confounding factors, elevated blood pressure (OR, 1.771; 95% CI, 1.246-2.519), low HDL-C (OR, 1.391; 95% CI, 1.053-1.836) and number of components of metabolic syndrome (OR, 1.561; 95% CI, 1.103-2.209) were significantly associated with carotid atherosclerosis. The diagnosis of metabolic syndrome per se might not adequately identify subjects at increased cardiovascular risk.

[Application of interlocking detachable coil (IDC) in superselective bronchial artery embolization]

Bronchial artery embolization (BAE) is almost the only effective nonsurgical treatment for massive hemoptysis. Metallic coils with plastic fibers are widely used as embolic materials. We have introduced an interlocking detachable coil (IDC) for BAE. IDC is a mechanically detachable coil, allowing the operator to seek the ideal shape until its final release. We compared hemoptysis patients treated with conventional metallic coils (24 patients, non-IDC group) with those treated with conventional coils and IDCs (26 patients, IDC group). The hemoptysis rate after three months is significantly lower in the IDC group than in the non-IDC group (7.7% vs. 16.3%, p = 0.035 Fisher's exact method). Total procedure time (in staged or repetitive BAE cases, procedure times are added together) is significantly shorter in the IDC group than in the non-IDC group (3.4 +/- 1.4 hours vs. 4.4 +/- 2.5 hours, p = 0.040 unpaired t-test). IDC is a useful device for BAE. This is the first-ever report documenting the usefulness of IDC for BAE.

Glomerular hyperfiltration, high renin, and low- extracellular volume in high blood pressure

Abnormal renovascular resistance and glomerular filtration rate are characteristic of established hypertension and may also be involved in its pathogenesis. To determine renal and body fluid correlates of the predisposition to high blood pressure, we examined 100 healthy young adults with high or low blood pressure. Within each group, half had parents with high blood pressures, and half had parents with low blood pressures. Renal function and hemodynamics, body fluid volumes, and relevant hormones and genotypes were measured. Subjects with high personal and parental blood pressures had the highest levels of glomerular filtration rate (P<0.02) and plasma active renin concentration and low levels of exchangeable sodium and plasma volume (P<0.02). High glomerular filtration rate was not associated with differences in urinary kallikrein or prostaglandins. Polymorphisms of the renin, angiotensin-converting enzyme, and angiotensinogen genes were not associated with differences in glomerular filtration rate or renin. Subjects with high personal, but low parental, blood pressures had low exchangeable sodium and plasma volumes (P<0.02) but normal glomerular filtration rates. In this population, extracellular volume depletion and high renin are correlates of high blood pressure in early adulthood, and glomerular hyperfiltration is a feature of those who also have familial predisposition to high blood pressure.

Human alpha-adducin gene, blood pressure, and sodium metabolism

The adducin genes contribute significantly to population variation in rat blood pressure and cell membrane sodium transport. The 460Trp mutation of the human alpha-adducin gene has been associated with hypertension, in particular hypertension sensitive to sodium restriction. We studied the relationship between the 460Trp mutation and population variation in blood pressure and sodium metabolism. From 603 Scottish families, we selected 151 offspring and 224 parents with blood pressures in either the upper (high) or bottom (low) 30% of the population distribution and measured the 460Trp mutation using allele-specific hybridization. In offspring, we also measured exchangeable sodium, plasma volume, and total body water. Plasma levels of components of the renin-angiotensin system, atrial natriuretic peptide, and cellular sodium and transmembrane sodium efflux were also estimated. The overall frequency of the 460Trp mutation was 27.1%. In offspring and parent groups, we found no difference in the genotype or allele frequencies of the 460Trp mutation between subjects with high or low blood pressure. There was no overall association between the alpha-adducin genotypes and blood pressure variation. In offspring, the 460Trp mutation was not associated with any significant differences in body fluid volumes or exchangeable sodium; levels of plasma renin, angiotensin II, aldosterone, or atrial natriuretic peptide; intracellular sodium; or ouabain-sensitive transmembrane sodium efflux. These findings suggest that in our Scottish population, the alpha-adducin 460Trp polymorphism is not related to blood pressure and does not affect whole body or cellular sodium metabolism.

Angiotensin II type 1 receptor gene polymorphism is associated with increase of left ventricular mass but not with hypertension

A genetic epidemiologic approach is useful to elucidate the genes responsible for hypertension. Genetic analyses of the components of the renin-angiotensin system have succeeded in showing an association between their polymorphism and hypertension. Recently, two types of angiotensin II receptor were cloned and characterized. To examine the genetic contribution of angiotensin II type 1 receptor (AT1) and type 2 receptor (AT2) genes in human essential hypertension, a case-control study was performed in Japanese subjects. The study comprised 321 subjects with hypertension who satisfied the criteria for essential hypertension, together with 215 age and sex matched controls. The significance of the differences in genotype distribution between hypertensive and normotensive subjects was examined by chi2 analysis. Neither AT1 nor AT2 gene variants were associated with human essential hypertension in the Japanese subjects. However, the AT1 receptor gene polymorphism was associated with left ventricular mass index in normotensive subjects. The study results suggest that gene polymorphisms of both angiotensin II receptors are not directly involved in the increase of genetic risk for hypertension, but that the AT1 receptor gene might contribute genetically to the increase of left ventricular mass.

Upregulation of angiotensin-converting enzyme during the healing process after injury at the site of percutaneous transluminal coronary angioplasty in humans

BACKGROUND

Balloon injury models in rat have shown enhanced expression of ACE in the developing neointima. However, neointimal lesions in human coronary arteries are complex due to atherosclerosis and different types of wall laceration. This study was designed to investigate whether ACE is present in the neointima of humans, including patients with restenosis after percutaneous transluminal coronary angioplasty (PTCA).

METHODS AND RESULTS

Thirty-seven sites with angioplasty injury, obtained at autopsy, were studied using immunocytochemical techniques. Sites with injury limited to a fibrous plaque and those with injury extending into the media (<2 months after PTCA) showed fibrocellular repair tissue composed mainly of smooth muscle cells that were distinctly positive for ACE. In cellular reactions at the site of injury limited to the atheromatous plaque (<2 months after PTCA), the expression of ACE appeared first in accumulated macrophages; once smooth muscle cells appeared in the repair tissue, they also expressed ACE. At a later stage (3 months after PTCA), the number of cells with ACE expression decreased markedly; from 7 months on, ACE was no longer expressed within the repair tissue. Basically, there were no differences with regard to ACE expression during the healing process after PTCA between segments with and those without angiographic evidence of restenosis.

CONCLUSIONS

These results show that PTCA injury in humans results in upregulation of ACE at sites of active repair and, therefore, ACE could play an important role as one of the mediators of the healing process after PTCA.

Absence of genetic linkage of chromosome 5q31 with asthma and atopy in the general population

BACKGROUND

Clinical asthma is associated with increased serum total immunoglobulin E (IgE), atopy (skin prick test positivity to common aeroallergens), and bronchial hyperreactivity (BHR) to non-specific stimuli (positive methacholine challenge test). A region on chromosome 5q31-33 has been linked with increased total serum IgE and BHR. A study of the genetic linkage of this region with clinical asthma and atopy was therefore undertaken.

METHODS

A polymorphic microsatellite marker in chromosome 5q31 (D5S399) was studied in 119 sibling pairs recruited from the general population who shared asthma, atopy, and/or BHR. Based on our population distribution of 13 different alleles, it was expected that by chance alone sibling pairs would share on average 1.24 alleles and that a significant excess would indicate genetic linkage.

RESULTS

No evidence of linkage was found in 45 siblings concordant for asthma (shared alleles = 1.09, p = 0.95), in 103 sibling pairs with atopy (shared alleles = 1.18, p = 0.82), in 51 sibling pairs with BHR (shared alleles = 1.22, p = 0.62), or in 68 sibling pairs who shared atopy in the absence of BHR (shared alleles = 1.22, p = 0.61). A slight non-significant excess of shared alleles (1.44, p = 0.11) was observed in siblings who shared BHR without atopy.

CONCLUSIONS

No evidence of genetic linkage of chromosome 5q31 with either clinical asthma or atopy was therefore detected in the population studied. Linkage between chromosome 5q and BHR needs further investigation.

Predominance of nocturnal sympathetic nervous activity in salt-sensitive normotensive subjects

To assess the relation between salt sensitivity and autonomic nervous function by power spectral analysis of heart rate variability in normotensive subjects, low and high salt diets were given to 13 normotensive men (aged 25 to 39 years) for 4 days each. Autonomic function was assessed by power spectral analysis of R-R intervals based on an autoregressive algorithm from 24-h Holter electrocardiogram. Subjects whose mean blood pressure was increased more than 3 mm Hg by high salt diet were defined as salt sensitive (SS, n = 5), and the remainder as salt resistant (SR, n = 8). Using the low frequency (LF, 0.1 Hz) and high frequency (HF, 0.25 Hz) components, the LF to total power ratio (%LF) was used as a marker of sympathetic activity, and the HF to total power ratio (%HF) as a marker of parasympathetic activity. Compared to the daytime, SR revealed a decrease in %LF and an increase in %HF during the night on both diets. In SS, these circadian changes were observed only during low-salt diet. During the night, SS showed a higher %LF and a lower %HF than SR. Plasma catecholamines tended to be decreased by the high sodium diet in SR but not in SS subjects. These results suggest that the persistent nocturnal predominance of sympathetic nervous activity in a salt-sensitive men may contribute to the subsequent increase of blood pressure in these subjects.

Links between hypertension and myocardial infarction

The mechanisms through which hypertension contributes to the occurrence of myocardial infarction should be discussed from two points of view: (1) common risk factors for the two diseases, such as genetic risk, insulin resistance, sympathetic hyperactivity, and vasoactive substances such as angiotensin K, and (2) linking factors that are induced by hypertension and contribute to the development of atherosclerosis and myocardial infarction, such as atherosclerosis and left ventricular hypertrophy. Mechanical stress on blood vessels because of high blood pressure is an especially important factor in endothelial dysfunction, the progression of atherosclerosis, and plaque rupture. This article concentrates on these factors from the perspective of their relationship with the renin-angiotensin system, because recent multicenter trials have demonstrated that angiotensin-converting enzyme inhibitors are effective for preventing recurrence of myocardial infarction.

Enhanced predictability of myocardial infarction in Japanese by combined genotype analysis

To explore the genes responsible for myocardial infarction and restenosis after percutaneous transluminal coronary angioplasty, we performed association studies of the polymorphisms of the angiotensinogen and angiotensin-converting enzyme (ACE) genes. In the first study, normotensive myocardial infarction patients (n = 103) and control subjects (n = 103), who were matched for established risk factors with the myocardial infarction patients, were randomly selected. The angiotensinogen-TT genotype (T indicates threonine instead of methionine at position 235) was more frequent in the myocardial infarction group than in the control group (P < .05). The ACE-DD genotype (D indicates a deletion polymorphism in intron 16) was also more frequent in the myocardial infarction group (P < .0001). The odds ratio estimated by the combined analysis of the angiotensinogen-TT and ACE-DD genotypes (11.2) was markedly increased compared with that estimated separately from the angiotensinogen-TT (1.75) or ACE-DD (4.43) genotype. In the second study, we investigated 91 consecutive patients with acute myocardial infarction who underwent successful direct angioplasty. Combined analysis showed that the angiotensinogen-TT genotype did not enhance the predictability of myocardial infarction from the ACE-DD genotype. In conclusion, the angiotensinogen-TT genotype is a predictor for myocardial infarction, as well as the ACE-DD genotype, and the combined analysis of the angiotensinogen-TT and ACE-DD genotypes further enhanced the predictability of myocardial infarction in Japanese, suggesting its future clinical usefulness.

Association analysis of a polymorphism of the angiotensinogen gene with essential hypertension in Japanese

An association study of the polymorphism of the angiotensinogen gene, consisting of T-->C transition at nucleotide 704 in exon 2, with essential hypertension in the Japanese population was performed by restriction fragment length polymorphism (RFLP). The allele which contained the Tth 111-I restriction site in the presence of C transition was designated 'a' and the allele that lacked restriction site was designated 'A'. The frequency of aa genotype in our normotensive group was higher than the previously reported values in Caucasians. In spite of the high frequency of the aa genotype in Japanese, the aa genotype was significantly more frequent in 108 hypertensives than in 104 normotensive subjects compared with the two other genotypes (P = 0.009). These results suggested that this molecular variant of the angiotensinogen gene may be a preserved inherited predisposition for essential hypertension in various ethnic groups, including Caucasians and Japanese.

The effects of central administration of angiotensin II type-1 receptor antagonist, CV-11974, in nephrectomized spontaneously hypertensive rats

1. The role of the brain renin-angiotensin system in the pathogenesis of genetic hypertension was evaluated using a specific non-peptide angiotensin II type-1 receptor antagonist, TCV-116. 2. CV-11974 (active metabolite of TCV-116) was acutely injected either intravenously (i.v.) or intracerebroventricularly (i.c.v) in male spontaneously hypertensive rats (SHR; 12 week old). In separate groups of nephrectomized and sham-operated SHR, graded doses of CV-11974 were administered either i.v. or i.c.v. for 2 days using an osmotic minipump. In another group, the effects of nephrectomy on the depressor effect of chronic treatment with CV-11974 were investigated. Haemodynamics at three points: before infusion, before nephrectomy and 48 h after nephrectomy, were monitored. 3. Acute i.c.v. injection of CV-11974 decreased blood pressure in the presence of the kidney. Prolonged i.c.v. administration of the drug for 2 days decreased blood pressure even at the lowest dosage, which had no hypotensive effects when given i.v. The hypotensive effect of centrally administered CV-11974 was noted even 48 h after bilateral nephrectomy. 4. These results suggest that the brain renin-angiotensin system has a primary role in the maintenance of hypertension after eliminating the circulating renin-angiotensin system in SHR.

Association analysis of a polymorphism of the angiotensin converting enzyme gene with essential hypertension in the Japanese population

An association study of the insertion/deletion (I/D) polymorphism located in intron 16 of the ACE gene with essential hypertension in the Japanese population was performed. The 287 bp I/D polymorphism was detected by polymerase chain reaction. Derived allele frequencies for insertion and deletion were not significantly different between 133 hypertensive and 104 normotensive subjects. A significant relationship between I/D polymorphism and plasma ACE activity was observed in the normotensive group, but not in hypertensives. These results suggest that I/D polymorphism of the gene is not implicated in Japanese hypertensive subjects, and that studies involving various ethnic groups are important.

[Case report of a patient with pseudohypoparathyroidism associated with slight increase in serum level of unconjugated bilirubin]

We treated a 29-year-old male patient with pseudohypoparathyroidism type I, who showed a slight increase in serum indirect bilirubin without any signs of liver dysfunction. Serum levels of total, direct and indirect bilirubins were 2.4, 0.7 and 1.7mg/dl, respectively (normal ranges: 0.2-0.8, 0-0.2 and 0.2-0.6mg/dl, respectively). The cause of the increases in serum bilirubin levels was not clear; however, hemolytic anemia, hereditary unconjugated hyperbilirubinemia or ineffective erythropoiesis were ruled out as causes for the increase, since 1) his serum level of haptoglobin was normal, 2) increase in serum level of indirect bilirubin 120 minutes after the infusion of 50mg nicotinic acid was within the normal range, and 3) severe anemia was not observed. Osmotic fragility of his circulating red blood cells was also within normal range. Three other patients with pseudohypoparathyroidism visiting our clinic also showed slightly high levels of serum indirect bilirubin, although four outpatients with idiopathic hypoparathyroidism showed no such abnormality. Abnormality in the responsiveness to parathyroid hormone and/or to that in the cyclic AMP productivity in this disease may cause the increase in the circulating unconjugated bilirubin.