Early arterial lesions in maturity onset diabetes mellitus detected by an ultrasonic technique

Soluble tumor necrosis factor receptor 2 is independently associated with pulse wave velocity in nonobese Japanese patients with type 2 diabetes mellitus

The aim of the present study was to investigate the factors contributing to pulse wave velocity (PWV) in patients with type 2 diabetes mellitus. We focused on tumor necrosis factor (TNF) including soluble TNF receptors (sTNF-R1, sTNF-R2) in this study because TNF seems to be associated with the progression of atherosclerosis and because the relationships between PWV and TNF were not yet examined in type 2 diabetic patients. Univariate regression analyses showed that PWV was positively correlated with age (r=0.492, P<.001), diabetes duration (r=0.251, P=.021), systolic (r=.595, P<.001) and diastolic (r=0.248, P=.022) blood pressure, antihypertensive medication (r=0.268, P=.013), and the concentrations of sTNF-R1 (r=0.354, P=.001) and sTNF-R2 (r=0.415, P<.001). Although there was a positive correlation between TNF-alpha and sTNF-R1 (r=0.382, P<.001) or sTNF-R2 (r=0.394, P<.001), TNF-alpha was not associated with PWV. Other variables including gender were not associated with PWV. Multiple regression analyses showed that PWV was independently predicted by the level of age (F=15.1), systolic blood pressure (F=31.6), and sTNF-R2 (F=5.2), which explained 49.2% of the variability of PWV. From these results, it can be concluded that serum soluble TNF receptor is an important independent factor associated with aortic PWV in type 2 diabetic patients.

Sex differences in age-related stiffening of the aorta in subjects with type 2 diabetes

Hypertension and type 2 diabetes are associated with increased aortic pulse wave velocity (PWV), a measure of aortic stiffness and a powerful risk factor for cardiovascular events. The association of hypertension with type 2 diabetes may obscure the degree to which diabetes rather than hypertension contributes to an elevated PWV. The objective of this study was to determine whether the presence of type 2 diabetes is associated with an elevated PWV compared with nondiabetic subjects matched for mean arterial blood pressure. PWV was determined by measuring carotid to femoral transit time using applanation tonometry in 186 subjects (104 women) with (n=93) and without (n=93) type 2 diabetes. Diabetic and nondiabetic subjects were matched for age and mean arterial pressure (to +/-5 years and 5 mm Hg, respectively). PWV was strongly correlated with age and mean arterial blood pressure (R=0.59 and 0.29 respectively, each P<0.0001). PWV increased significantly more with age in women with diabetes (slope of regression line+/-SE: 0.19+/-0.03 m x s(-1) x year(-1)) than in nondiabetic women (0.08+/-0.02 m x s(-1) x year(-1), P<0.01 for difference). In men, however, the age-related increase in PWV was similar in diabetic (0.15+/-0.03 m x s(-1) x year(-1)) and nondiabetic subjects (0.13+/-0.03 m. s(-1) x year(-1), P=NS). The interaction of diabetic status with age and with sex was significant (P=0.01). Type 2 diabetes is associated with a greater age-related stiffening of the aorta in women compared with men, and this is not explained by hypertension.

Myogenic microvascular responses are impaired in long-duration type 1 diabetes

Post-ischaemic hyperaemia is a complex physiological response. Peak flow is predominantly an arteriolar myogenic response, whilst viscoelasticity of supplying arteries determines speed of vasodilatation. Impaired post-ischaemic hyperaemia has been described in neuropathic diabetic feet and might predispose to ulceration. However, the relationships of myogenic response and vasodilatation to diabetic control and microvascular complications are unclear. These relationships were therefore investigated using laser Doppler flowmetry to measure the hyperaemic response on the dorsum of the foot after 10 min ischaemia. Twenty control subjects were compared with 55 long-duration Type 1 diabetic patients in groups of uncomplicated, retinopathic and neuropathic patients. Peak flow (median (interquartile range)) was reduced from 1.40 (1.20-1.61) in control subjects to 1.15 (0.80-1.29), 1.08 (0.75-1.26), and 0.95 (0.62-1.29) arbitrary units in the diabetic groups respectively (p = 0.012-0.004). Time to half peak flow was shorter in neuropathic diabetic patients compared with all other groups: 9.5 (7-19), 14.5 (5-25), 12.5 (6-20), and 4 (3-6) s, respectively (p = 0.027-0.011). Neuropathic patients also had the steepest initial slope of vasodilatation. Thus, in long-duration diabetic patients, the myogenic peak post-ischaemic hyperaemic response is impaired, but this impairment is not specifically associated with microvascular complications and was not related to recent blood glucose control. The shortened time to half peak flow and rapid vasodilatation in neuropathic patients is likely to reflect increased rigidity of their arteries.

Risk factors for changes in aorto-iliac arterial compliance in healthy men

Doppler ultrasound was used to measure pulse wave velocity down the aorta and iliac arteries. Arterial wall compliance was calculated from pulse wave velocity in 45 apparently healthy men. Their arterial compliance fell significantly with advancing age, raised blood pressure, increased serum cholesterol and triglyceride levels, and reduced serum high density lipoprotein cholesterol levels. The correlation between compliance and age was independent of the other risk factors, and the correlation between compliance and lipid status was independent of age and blood pressure. There was no significant correlation between compliance and area under the glucose tolerance curve.

[Pathogenesis and clinical significance of Mönckeberg medial calcinosis]

Medial calcinosis of Mönckeberg is frequently observed in peripheral arteries of diabetics with neuropathy. The cause of this vessel alteration is unknown and the clinical significance has been questioned. Six to eight years after uni- or bilateral lumbar sympathectomy 60 patients were investigated radiologically for medial calcinosis of foot arteries. Of 60 patients, 55 had Mönckeberg's sclerosis. In 93% of the patients who had undergone bilateral operation medial calcification was seen in both feet. After unilateral sympathectomy the incidence of medial calcinosis on the operated side was significantly higher than on the non-operated side (88% versus 18%, p less than 0.01). There was no significant difference between diabetics and non-diabetics. These findings suggest that medial calcification is related to autonomic neuropathy of peripheral vessels. Fifty-two of 160 patients (32.5%) with severe arterial occlusive disease of the lower limbs showed medial calcification of foot arteries. Mönckeberg's sclerosis was significantly associated with the peripheral type of vascular disease (p less than 0.025). Two groups of patients with the same stage of occlusive vascular disease but without (group A) and with (group B) medial calcification were examined by Doppler ultrasound. In group A the mean ankle pressure (pD) was 51 mm Hg lower than the Riva-Rocci pressure (pRR). In spite of the severe ischemia mean pD in group B exceeded pRR by 14 mm Hg. Of the patients of group B 63% had a pD-pRR value greater than or equal to 0 mm Hg. In group A no positive difference pD-pRR could be shown.(ABSTRACT TRUNCATED AT 250 WORDS)

Elastic modulus in young diabetic patients (ultrasound measurements of pulse wave velocity)

Aim of this study is to confirm the validity of non-invasive evaluation with Doppler C.W. in the study of arterial diseases and in the identification of pre-clinical arterial lesions. We studied twenty-eight children suffering from diabetes mellitus, and dependent on insulin and a control group composed of twenty-eight healthy persons. All subjects were studied using the methodology of the transit time for the determination of the elastic modulus of the lower limb arterial wall and results were analysed according to a statistical method. Although the groups were small, an increase in pulse wave velocity was noted in diabetic children and a significative correlation was found between the elastic modulus and duration of diabetes.

Blood flow in the diabetic neuropathic foot

The mechanisms which underlie the development of Charcot joints and foot ulceration are poorly understood. The present study using non-invasive Doppler techniques demonstrates that in the neuropathic leg, the arteries are rigid, peripheral blood flow is increased and associated with arteriovenous shunting. We studied 10 diabetics with severe neuropathy (including five with Charcot changes), 16 diabetics without neuropathy and 10 control subjects. Markedly abnormal blood velocity profiles (sonograms) were demonstrated only in those patients with severe neuropathy. They showed increased diastolic flow (indicated by a reduced Pulsatility Index of 2.88 +/- 0.8 (mean +/- SD) compared with 9.53 +/- 4.0 (p less than 0.001) in the diabetics without neuropathy and 10.8 +/- 3.7 (p less than 0.001) in the control subjects) suggesting arteriovenous shunting. Increased rigidity was indicated by decreased transit times -57 +/- 6.3 ms (mean +/- SD) in the diabetics with neuropathy compared with 66 +/- 7.6 ms (p less than 0.01) in the diabetics without neuropathy and 67 +/- 9.1 ms (p less than 0.05) in the control subjects. This was accompanied by raised ankle systolic pressures -199 +/- 22 mmHg (mean +/- SD) in the diabetics with neuropathy compared with 151 +/- 15 mmHg, (p less than 0.001) in the diabetics without neuropathy and 146 +/- 18 mmHg (p less than 0.001) in the control subjects. Medial wall calcification occurred almost exclusively in the neuropathic subjects. These alterations in blood flow which include arteriovenous shunting may be important in the pathogenesis of complications of the neuropathic leg.