White-Coat Hypertension Contributes to the Presence of Carotid Arteriosclerosis

White-coat effect on orthostatic hypotension: a nationwide survey of Japanese general practitioners

OBJECTIVE

The relationship between the white-coat effect (WCE), defined as white-coat hypertension under treatment, and the frequency of orthostatic hypotension (OH) is not known. We conducted an orthostatic test in patients with WCE to determine the frequency of OH.

METHODS

This was a cross-sectional study of 5631 patients with hypertension visiting general practitioners nationwide, in which 4305 patients with hypertension recorded their home blood pressure (BP) and consented to the orthostatic test. Patients with hypertension were divided into four groups: controlled hypertension (CHT), masked hypertension (MHT), sustained hypertension (SHT), and WCE. The orthostatic test was performed, and BP and pulse rate were measured immediately and 1 min after orthostasis.

RESULTS

The OH frequencies immediately after standing in CHT, WCE, SHT, and MHT patients were 7, 11.7, 12.1, and 6.6%, respectively, and those at 1 min after standing were 7.1, 13.1, 11.6 and 6.9%, respectively (Chi-square test, P < 0.01, respectively). Logistic regression analysis was performed to examine the relationship between WCE and the frequency of OH. The frequency of OH immediately after standing was significantly increased [adjusted odds ratio (AOR), 1.702; 95% confidence interval (CI), 1.246-2.326; P < 0.01]. The frequency of OH at 1 min after standing was also significantly higher (AOR, 1.897; 95% CI, 1.396-2.578; P < 0.01).

CONCLUSION

When the standing test was performed for patients with WCE, the frequency of OH increased. Thus, it is important to recognize the possibility of OH in patients with WCE to avoid adverse events associated with excessive hypotension.

Cardiovascular Alterations and Management of Patients With White Coat Hypertension: A Meta-Analysis

A large and growing body of literature has focused on the association between "white coat hypertension" (WCH) and the underlying target organ damage. The evidence suggests that WCH is may not an entirely benign phenomenon. However, whether patients with WCH should receive antihypertensive drugs is unresolved. Therefore, we performed a meta-analysis to fully determine the ability of WCH to alter cardiovascular structure and to determine whether patients with WCH could benefit from drug intervention. Medline, EMBASE, and the Cochrane Library were searched from inception through 21 Oct 2019. A total of 25 studies (8,100 individuals) were included. In participants with WCH, values of aortic pulse wave velocity, augmentation index, intima-media thickness, interventricular septum thickness, left ventricular posterior wall thickness, and left ventricular mass index were lower than those with sustained hypertension, but greater than those in the normotensive group. Of note, antihypertensive drug therapy did not reduce the risk of cardiovascular events in patients with WCH. WCH is accompanied by alterations of cardiovascular structure; however, the benefits from antihypertensive therapy are limited.

The significance of blood pressure variation and metabolic risk factors in patients with different stages of hypertension

Objectives Blood pressure variation (BPV) and metabolic syndrome is an independent risk factor for cardiovascular events. Ambulatory blood Pressure (ABP) has been shown to be more closely related to cardiovascular events in hypertensive patients than conventional office BP (OBP). Using both OBP and ABP, 4 groups of patients were identified: (1) normotensive patients (NT); (2) white coat hypertensives (WCHT); (3) masked hypertensives (MHT); and (4) sustainedhypertensives (SHT). We investigated the significance of BPV and metabolic risks of these 4 groups. Methods This study is a retrospective analysis of patients between January 2008 and May 2013. Echocardiography and 24 hour ABP monitoring were performed. Results BMI was significantly higher in the MHT compared with the NT. There were progressive increases in fasting glucose level from NT to WCHT, MHT, and SHT.MHT and SHT had higher 24h and nighttime BPV than NT.MHT was significantly related with BMI (r = 0.139, P = 0.010), creatinine (r = 0.144, P = 0.018), fasting glucose (r = 0.128, P = 0.046), daytime systolic BPV (r = 0.130, P = 0.017), and daytime diastolic BPV (r = 0.130, P = 0.017). Dyslipidemia (r = 0.110, P = 0.043), nighttime systolic BPV (r = 0.241, P &lt; 0.001) and nighttime diastolic BPV (r = 0.143, P = 0.009) shown correlation with SHT. In multivariate logistic regression, MHT was independently associated with Body mass index (OR 1.086, 95% CI 1.005–1.174, P = 0.038) and creatinine (OR 1.005, 95% CI 1.001–1.010, P = 0.045). Conclusions BPV and metabolic risk factors were found to be greater in MHT and SHT compared with NT and WCHT. This suggests that BPV and metabolic risks may contribute to the elevated cardiovascular risk observed in patients with MHT and SHT.

Differential expression of hypertension-associated microRNAs in the plasma of patients with white coat hypertension

White coat hypertension (WCH) is a high cardiovascular risk condition, and a fundamental understanding of the cause and pathophysiology of the disorder is still lacking. Recent studies demonstrated that microRNAs (miRNAs) are involved in hypertension; however, the roles of miRNAs in WCH are not known. The expressions of selected 10 miRNAs were investigated independently in plasma samples from 30 hypertension (HT) patients, 30 WCH patients, and 30 normotensive (NT) subjects. MiR-21, miR-122, miR-637, and let-7e expression levels were significantly upregulated in the HT group compared with the NT groups (P = 0.017, P = 0.022, P = 0.048, and P = 0.013, respectively). MiR-122 and miR-637 expressions were also significantly upregulated in the WCH group compared with the NT group (P = 0.048 and P = 0.039, respectively). MiR-296-5p expression level was significantly downregulated in HT patients and upregulated in the WCH patients compared with the NT group (P = 0.049 and P = 0.039, respectively). Additionally, the ambulatory 24-hour and daytime systolic and diastolic blood pressures were negatively correlated with miR-296-5p. MiR-296 and miR-637 had area under the curve (AUC) values of 0.778 and 0.774, respectively, which demonstrates their sufficiency to distinguish WCH from NT individuals. MiR-296 and miR-637 had AUC values of 0.868 and 0.680, respectively, which shows their potential to distinguish WCH from HT individuals. We report for the first time a plasma miRNA profile for WCH patients and demonstrate a novel link between miRNA and WCH. These findings may reveal crucial insights into the development of WCH.

White-coat hypertension

1. Numerous studies have examined whether white-coat hypertension (WCHT) is associated with increased cardiovascular risk, but with definitions of WCHT that were not sufficiently robust, results have been inconsistent. The aim of the present review was to standardize the evidence by only including studies that used a definition of WCHT consistent with international guidelines. 2. Published studies were reviewed for data on vascular dysfunction, target organ damage, risk of future sustained hypertension and cardiovascular events. 3. White-coat hypertension has a population prevalence of approximately 15% and is associated with non-smoking and slightly elevated clinic blood pressure. Compared with normotensives, subjects with WCHT are at increased cardiovascular risk due to a higher prevalence of glucose dysregulation, increased left ventricular mass index and increased risk of future diabetes and hypertension. 4. In conclusion, management of a patient with WCHT should focus on cardiovascular risk factors, particularly glucose intolerance, not blood pressure alone.

Endothelial damage in white coat hypertension: role of lectin-like oxidized low-density lipoprotein-1

The aims of this study included an examination of soluble lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (sLOX-1) levels in hypertensive (HT) patients. Another aim examined sLOX-1 associations with oxidized LDL (oxLDL), nitric oxide synthase (eNOS) and nitric oxide (NOx). A final aim was to compare these parameters between HT patients, white-coat hypertensive (WCH) patients and healthy controls. The three groups, HT, WCH and controls, were comprised of 35 patients each. sLOX-1 and oxLDL levels were significantly increased in WCH and HT patients compared with controls. The eNOS activation was significantly lower in HT than in the control group. sLOX-1 and oxLDL levels were significantly negatively correlated with eNOS levels in the WCH and HT groups. Carotid intima-media thickness (CIMT) measurements were significantly higher in the WCH and HT groups compared with controls. There was a significant positive correlation between CIMT and sLOX-1 and oxLDL; however, there was a negative correlation with eNOS in WCH. Regression analysis revealed that sLOX-1 was the variable that had a significant effect on blood pressure (P<0.001, odds ratio (95% confidence interval=23.273 (5.843-92.688)). A possible endothelial impairment may act as a cardiovascular risk factor in WCH. Necessary measures should be considered in terms of atherosclerosis risk with HT, especially in early identification of endothelial damage by looking at sLOX-1 levels. We believe sLOX-1 levels are strong biomarkers for determining early endothelial damage in HT, and especially in WCH patients.

Comparison of demographic, clinical, and laboratory parameters between patients with sustained normotension, white coat hypertension, masked hypertension, and sustained hypertension

BACKGROUND

After measurement of office blood pressure (BP) and ambulatory BP monitoring (ABPM), 4 groups of patients were identified namely: (i) sustained normotensive patients (BPs are normal both clinically and by ABPM); (ii) white coat hypertensive patients (clinical BP were above limits, but ABPM were normal); (iii) masked hypertensive patients (clinical BP were normal, but ABPM were high); (iv) sustained hypertensive patients (both office and ABPM were high). The exact pathophysiologic mechanisms of these conditions are not exactly known. Besides in the literature there are only few studies that compare the 4 groups of patients together. Thus the study was carried out to compare patients with sustained normotension (SNT), white coat hypertension (WCHT), masked hypertension (MHT), and sustained hypertension (SHT).

METHODS

All patients underwent history taking, physical examination, laboratory analysis, and ABPM. They were referred to the cardiology department for echocardiographic evaluation.

RESULTS

In total 85 patients with SNT, 112 patients with WCHT, 31 patients with MHT, and 81 patients with SHT were included. Going from SNT to SHT, body mass index (p<0.0001), waist circumference (p<0.0001), fasting blood glucose (p=0.002), and uric acid (p=0.029) rose progressively. Presence of metabolic syndrome was also highest in SHT and lowest in SNT (p<0.0001).

CONCLUSION

Most of the metabolic risk factors were higher in patients with MHT and SHT when compared to SNT and WCHT. Studies are needed to determine whether metabolic risk factors play a causative role for the development of MHT and SHT.

Ambulatory blood pressure monitoring in the elderly

The incidence of hypertension is high in the elderly and is present in 2/3 of the patients older than 65 years. Prevalence can reach 90% in patients older than 80 years. The presence of isolated systolic hypertension (ISH) is characteristic of this population. However, the prevalence of hypertension by ambulatory blood pressure monitoring (ABPM) is not well known. In this study, we analyzed the special characteristics of hypertension in this population, giving special emphasis on ABPM readings.

Diagnosis and management of patients with white-coat and masked hypertension

White-coat hypertension is characterized by an elevation in clinic blood pressure but normal home or ambulatory blood-pressure values, whereas patients with masked hypertension have normal clinic blood pressure and elevated ambulatory or home blood-pressure load. Both white-coat and masked hypertension are frequent clinical entities that need appropriate recognition and a close diagnostic follow-up. White-coat and masked hypertension seem to be associated with organ damage and increased cardiovascular risk, although not invariably. In addition, patients with masked or white-coat hypertension have an increased risk of abnormalities affecting their glucose and lipid profiles. Therefore, the diagnosis of these conditions should be accurate and include the assessment of cardiovascular as well as of metabolic risk. Once diagnosed, first-line therapeutic interventions should be nonpharmacological and aim at lifestyle changes, but drug treatment can be indicated, particularly when the patient's cardiovascular risk profile is elevated or when target-organ damage is detected.

Aging and hypertension

Aging is known to be a dominant risk factor in the progression of hypertension. Thus, accompanied by an increasing mean age of the population in developed countries, prevention and management of hypertension in the elderly is a task of pressing urgency. Age-associated blood pressure elevation is a result of the aging process in organ systems, which play a key role in the regulation of blood pressure. In addition, advanced aging of the cardiovascular system contributes to the presence of a varied phenotype in elderly hypertension, such as nocturnal hypertension and morning hypertension. Therefore, in order to detect and treat age-associated hypertension appropriately, it is important to assess ambulatory blood pressure monitoring throughout the 24-h period.

Topography and severity of coronary artery disease in white-coat hypertension

BACKGROUND

White-coat hypertension (WCH) has been evaluated as a risk factor for cardiovascular disease. In this study, the role of WCH is evaluated in a cohort of patients with suspected coronary artery disease with both coronary angiography and non-invasive techniques.

METHODS

One hundred patients with suspected coronary artery disease underwent coronary angiography, 24-h ambulatory blood pressure monitoring (ABPM), and ultrasound imaging of the myocardium and carotids. The lesions in percentage of stenosis in the left coronary artery stem (LM), left anterior descending ramus (LAD), left circumflex artery (LCX), diagonal artery (D1), and right coronary artery (RCA), along with the Gensini score (GS), were recorded. After a series of manual blood pressure measurements, the patients were divided into two groups (patients with and patients without WCH).

RESULTS

GS was higher in the WCH group (P=0.042), a difference that could be attributed to lesions in the LAD (P=0.007). GS correlated significantly with left ventricular end-diastolic diameter (LVEDD - P=0.041), left ventricular end-systolic diameter (LVESD - P=0.005), end-diastolic volume (EDV - P=0.042), end-systolic volume (ESV - P=0.004), LvMass/BSA (P=0.012), right internal carotid artery intima-media thickness (RICA - P=0.018), left internal carotid artery intima-media thickness (LICA - P=0.021), and their mean (MICA - P=0.005) in the WCH group but not in normotensives.

CONCLUSIONS

Coronary disease may be more severe among patients with WCH than among those without. In this group, data from myocardial and carotid ultrasound may help to estimate coronary artery disease.

Prevalence of white coat hypertension in underweight and overweight subjects

The aim of the present study was to determine if there is any association between white coat hypertension (WCH) and body mass index. The study was performed in two phases. In the first phase, we studied consecutive underweight patients, while in the second phase, age-matched consecutive normal weight, overweight, and obese cases were studied. Although we detected 61 cases in the underweight group with a mean age of 24.1 years, we could only detect 12 age-matched cases in the obesity group, and thus the obesity group was not used for comparison. When we looked at the prevalences of sustained normotension (NT), WCH, and HT in the groups, there were gradual and significant increases in the prevalences of WCH in addition to the gradual and significant decreases in the sustained NT from the underweight towards the normal weight and overweight groups. Eventually, only 31.5% of the overweight group had sustained NT, even though the mean age of the cases was very young. Due to the gradually increased prevalence of WCH from the underweight towards the normal weight and overweight groups, parallel to the already known increasing prevalences of HT, type 2 diabetes mellitus, hyperbetalipoproteinemia, dyslipidemia, and coronary heart disease and the very low prevalence of sustained NT among the overweight cases even in the early decades here, WCH should preferentially be accepted as an alarming sign of excess weight and many associated disorders in the future, rather than just being considered a predisposing factor of HT or atherosclerosis alone.

Factors influencing white-coat effect

BACKGROUND

The transient blood pressure (BP) rise during clinical visits is usually referred to as white-coat effect (WCE). The aim of the present study was to investigate factors that may influence the WCE.

METHODS

A total of 2004 subjects underwent office BP measurements and 24-h ambulatory BP monitoring (ABPM) on the same day. The WCE was estimated as the difference between office and average daytime ambulatory BP (ABP). According to the office and daytime BP values, the study population was divided into normotensives (NTs), white-coat hypertensives (WCHs), masked hypertensives (MHTs), and sustained hypertensives (SHTs). Statistical analyses were performed using one-way analysis of variance and multiple linear regression models.

RESULTS

The mean systolic and diastolic WCE was 9 +/- 16 and 7 +/- 12 mm Hg, respectively. In the entire group of patients, multiple linear regression models revealed independent determinants of systolic WCE in the following rank order: office systolic BP (SBP) (beta = 0.727; P < 0.001), female gender (beta = 0.166; P < 0.001), daytime SBP variability (beta = 0.128; P < 0.001), age (beta = 0.039, P = 0.020), and smoking (beta = 0.031, P = 0.048). A 1.0 mm Hg increase in daytime SBP variability correlated with an increment of 0.589 mm Hg (95% confidence intervals, 0.437-0.741) in the systolic WCE. The regression analyses for diastolic WCE revealed the same factors as independent determinants. A 1.0 mm Hg increase in daytime diastolic BP (DBP) variability was independently associated with an increment of 0.418 mm Hg (95% confidence intervals, 0.121-0.715) in the diastolic WCE.

CONCLUSIONS

Factors such as gender, age, smoking, office BPV and daytime BPV may exert an important influence on the magnitude of the WCE.

Prevalence, predictive factor, and clinical significance of white-coat hypertension and masked hypertension in Korean hypertensive patients

BACKGROUND

The prevalence and clinical significance of white-coat hypertension (WCHT) and masked hypertension (MHT) are unknown in Koreans. Here we measure the frequency of WCHT and MHT in hypertensive subjects and identify the epidemiologic and/or clinical factors that predict it in Korean subjects.

METHODS

This study is a retrospective analysis of a random sample from February 2004 to October 2005. All patients had measurements of blood pressure (BP) in the clinic and 24-hour ambulatory blood pressure monitoring (ABPM). Subjects were classified into four groups on the basis of daytime ambulatory BP and clinic BP level: 1) Normotension (NT), 2) MHT, 3) WCHT, and 4) sustained hypertension (SHT).

RESULTS

For all 967 patients, the mean clinic BP was 157.7 +/- 22.0/ 95.3 +/- 13.1 mmHg, and the mean daytime ambulatory BP was 136.4 +/- 15.0/ 86.2 +/- 10.7 mmHg. The NT, MHT, WCHT, and SHT groups consisted of 51 (5.3%), 55 (5.7%), 273 (28.2%), and 588 (60.8%) subjects, respectively. The left ventricular mass index was significantly higher in SHT than in the other groups, and was positively correlated with BP, especially ABPM. Compared with NT, the factors associated with MHT were younger age, male gender, higher BMI, clinic BP > or = 130 mmHg, and alcohol consumption. Compared with SHT, the factors associated with WCHT were female gender, lower BMI, and clinic BP < 150 mmHg.

CONCLUSIONS

WCHT and MHT were prevalent in the hypertensive population. ABPM was more predictive of target organ damage than clinic BP, and could be useful in identifying subjects at risk for WCHT and MHT.

Comparison of Pulse Wave Analysis Between Persons With White Coat Hypertension and Normotensive Persons

White coat hypertension (WCH) is considered by some but not all investigators to be a benign condition without increased cardiovascular risk. Pulse wave analysis is a noninvasive method to measure how the reflected pressure wave interacts with central aortic blood pressure (BP) and to assess how it is related to vascular stiffness. The purpose of the study was to compare central aortic BP in normotensive and WCH participants. WCH participants were identified after ambulatory BP monitoring. Normotensive participants served as controls. Using radial artery applanation tonometry, aortic pulse wave analysis was performed. Augmentation index (AI), AI75, and differences in systolic BP between central aortic and peripheral vasculatures were calculated. Results show a difference in AI, AI75, (AI standardized to a heart rate of 75 beats per minute), and central aortic systolic pressures between WCH and normotensive participants. The WCH group had significantly higher systolic BP and pulse pressure; however, these were still within the normal range. In summary, WCH participants had increased central aortic pressures compared with normotensives, supporting the potential for increased cardiovascular risk in WCH.

Masked Nocturnal Hypertension and Target Organ Damage in Hypertensives with Well-Controlled Self-Measured Home Blood Pressure

It has been reported that masked hypertension, a state in which patients show normal clinic blood pressure (BP) but elevated out-of-clinic BP by self-measured home BP, is a predictor of cardiovascular morbidity much like sustained hypertension. In addition, nocturnal BP is closely associated with cardiovascular disease. This might mean that ambulatory and self-measured home BP monitoring each provide independent information. We performed ambulatory BP monitoring, self-measured home BP monitoring, echocardiography and carotid ultrasonography in 165 community-dwelling subjects. We subclassified the patients according to the ambulatory and self-measured home BP levels as follows: in the masked nocturnal hypertension group, the self-measured home BP level was <135/85 mmHg and the ambulatory nocturnal BP level was >or=120/75 mmHg; in the normotensive group, the self-measured home BP level was <135/85 mmHg and the ambulatory nocturnal BP level was <120/75 mmHg. The intima-media thickness (IMT) and relative wall thickness (RWT) were greater in the masked nocturnal hypertension group than in the normotensive group (IMT: 0.76+/-0.20 vs. 0.64+/-0.14 mm, p<0.05; RWT: 0.50+/-0.14 vs. 0.41+/-0.10, p<0.05). Even in hypertensives with well-controlled self-measured home BP, elevated ambulatory nocturnal BP might promote target organ damage. We must rule out masked hypertension using self-measured home BP monitoring, and we might also need to rule out nocturnal masked hypertension using ambulatory BP monitoring.

Nanobacteria, HIV and magic bullets--update of perspectives 2005

In 1997 a Finnish group speculated on the presence of nanobacteria in vaccines. In 2001, a report on the identification of nanobacteria in a number of vaccines attracted much attention. Experiments indicated that viable nanobacteria are excreted via urine. Their extreme survivability suggests that prior to discussing any possible contamination of vaccines, sources and routes of natural infection need to be examined. In view of 30,000,000 HIV infections in sub-Saharan Africa, the recently reported occurrence of nanobacteria in HIV-infected patients deserves concern. Clearly, it could indicate the origin of a giant reservoir and dissemination cycle. Here we discuss novel therapeutic strategies to prevent or reduce nanobacterial infection. In regard of the rapid progress in this field, we start with a brief introductory summary, and analyze possible implications.

What a high prevalence of white coat hypertension in society!

BACKGROUND

There are many patients in society using antihypertensive medication, which has been initiated just after a single office measurement but actually they are normotensive and in contrast, there are many patients not using any antihypertensive medication because of a normal blood pressure (BP) at the doctor's office but they are actually hypertensive.

MATERIALS AND METHODS

We randomly took 438 consecutive patients. Clinical BP was measured by the same physician, and a 10-day twice daily home blood pressure measurement (HBPM) and 24-hour ambulatory blood pressure measurement (ABPM) were obtained.

RESULTS

Among 438 patients, 170 (38%) normotension (NT), 190 (43%) white coat hypertension (WCHT), 10 (2%) masked hypertension (MHT), and 68 (15%) sustained hypertension (HT) cases were detected. Although the prevalences of sustained HT and MHT increased by decade, the prevalence of WCHT was much higher in all decades until the eighth decade. Even in the second decade, its prevalence was 33% and higher than 45% in the third, fourth, and fifth decades of life. No statistically significant difference was found for number of WCHT, MHT, and sustained HT cases between ABPM and HBPMs.

CONCLUSION

HBPM should be the preferred method of diagnosis of WCHT, MHT, and sustained HT against conventional BPM at the doctor's office and even ABPM due to its simplicity and equal effectiveness with ABPM. It should be applied to every patient above the age of 40 years once a year due to high prevalences of sustained and masked HT cases. Additionally, due to the very high prevalences of WCHT even in the very early decades, WCHT should be thought of as a normal response of the body against various stresses and its management should be limited to annual follow-up with HBPMs.

C-Reactive Protein and B-Type Natriuretic Peptides in Never-Treated White Coat Hypertensives

Arterial hypertension has been associated with increased plasma concentrations of C-reactive protein (CRP) and B-type natriuretic peptide (BNP). This study tested the hypothesis that patients with white coat hypertension have lower plasma CRP and BNP concentrations than those with sustained hypertension. A total of 109 consecutive medical outpatients with never-treated office hypertension underwent ambulatory blood pressure monitoring and blood sampling to determine CRP and BNP concentrations. Patients with treated hypertension, lipid-lowering therapy, renal insufficiency or structural heart disease other than left ventricular hypertrophy were excluded. White coat hypertension was defined as office hypertension associated with mean daytime blood pressure values below 135/85 mmHg. A control group of 48 consecutive, age- and sex-matched patients without office hypertension were recruited during the same period. Twenty-six patients (24%) had white coat hypertension. There were no statistically significant differences in baseline variables between patients with sustained hypertension and white coat hypertensives, except for mean blood pressure values. Mean CRP was 3.2+/-5.1 mg/l in patients with white coat hypertension compared to 3.4+/-4.2 mg/l in those with sustained hypertension (p=0.79). Control patients had significantly lower CRP values than patients with either white coat or sustained hypertension (1.2+/-0.9 mg/l, p=0.002 and p=0.038, respectively). Mean BNP concentrations were 21+/-25 pg/l and 44+/-125 pg/l in white coat and sustained hypertensives, respectively (p=0.36). The plasma concentrations of CRP and BNP did not differ between patients with white coat hypertension and those with sustained hypertension.

On How Insulin May Influence Ageing and Become Atherogenic throughout the Insulin-Like Growth Factor-1 Receptor Pathway: In vitro Studies with Human Vascular Smooth Muscle Cells

BACKGROUND

It is known that growth factors play a role in ageing and atherogenesis, and insulin develops mitogenic activity in vitro.

OBJECTIVES

This study focuses on the pathway by which insulin induces proliferation and mobility in vascular smooth muscle cells (SMCs) compared with that of insulin-like growth factor-1 (IGF-1), because they are two basic phenomena for atherogenesis that could also help to understand the role of insulin in the ageing process.

METHODS

Bromodeoxyuridine DNA incorporation, chemotaxis and the appearance of membrane ruffles were measured in cultured SMCs after incubation with insulin or IGF-1 in the presence of insulin or IGF-1 receptor-blocking antibodies.

RESULTS

Insulin-induced SMC proliferation through the IGF-1 receptors; indeed, the blockade of insulin receptors does not inhibit the mitogenic influence of insulin. On the contrary, insulin-induced cell migration was inhibited by blocking the insulin receptor but not the IGF-1 receptor. Nevertheless, in less differentiated SMCs from non-confluent cultures, the migratory response was significantly higher and insulin lost its receptor specificity. It was stimulated through receptors both for insulin and IGF-1. In these cases the IGF-1 action was similar. Insulin-induced F-actin rearrangements took place through both types of receptors, but IGF-1 was a little more specific through its own receptors.

CONCLUSION

The pathway activated by insulin to induce SMC proliferation is not different from that of IGF-1, whereas the unspecific mechanism inducing mobility in growing cells seems to be related to a higher sensitivity response. Cells with the highest mitotic activity have the highest mobility in which stimulation of receptor specificity is lost for either insulin or IGF-1. Extrapolating these results to in vivo, insulin could become relevant for inducing stabilization and also side effects in ageing.

Relationships between Echocardiographic Findings, Pulse Wave Velocity, and Carotid Atherosclerosis in Type 2 Diabetic Patients

The purpose of the present study was to analyze the relationships between echocardiographic findings, brachial-ankle pulse wave velocity, and carotid atherosclerosis in type 2 diabetic patients. In 70 type 2 diabetic patients without cardiovascular disease, pulse wave velocity was measured using an automatic waveform analyzer, and the carotid plaque score was obtained by carotid ultrasonography. The left ventricular wall thickness and the indexes of left ventricular diastolic function (the peak velocity of early rapid filling [E velocity], the peak velocity of atrial filling [A velocity], and the E/A ratio) were obtained by echocardiography. Brachial-ankle pulse wave velocity correlated significantly with the carotid plaque score, but the correlation was weak (r=0.37, p=0.001). The brachial-ankle pulse wave velocity demonstrated a strong correlation with the A velocity (r=0.73, p<0.001), the ratio of E to A (E/A) (r=-0.63, p<0.001), and the deceleration time of the E velocity (r=0.48, p<0.001). Stepwise regression analysis showed that the A velocity (beta coefficient=0.42, p<0.001) and ventricular septal thickness at the left ventricular outflow tract (beta coefficient=0.27, p=0.001) were independently associated with brachial-ankle pulse wave velocity. Stepwise regression analysis indicated that ventricular septal thickness at the left ventricular outflow tract (beta coefficient=0.38, p=0.001) was independently associated with the plaque score. These results indicate that left ventricular diastolic dysfunction as revealed by increased peak velocity of atrial filling reflects arterial stiffening in type 2 diabetic patients. In addition, myocardial wall thickening at the left ventricular outflow tract reflects not only arterial stiffening but also carotid atherosclerosis. Therefore, these abnormal echocardiographic findings of left ventricular diastolic dysfunction and myocardial wall thickening may be useful markers of the presence of progressive arteriosclerosis in type 2 diabetic patients.