Subclinical atherosclerosis in normotensive subjects with exaggerated blood pressure response to exercise: role of inflammation

Exaggerated blood pressure response to exercise [EBPRE] is a predictor of future hypertension in normotensives. This study aimed to clarify whether EBPRE in normotensive subjects is associated with increased risk for atherosclerosis and to examine the possible role of inflammation in this process. A total of 90 normotensive male subjects were divided according to their blood pressure response to exercise into two groups; GI: 22 subjects with EBPRE and GII: 68 subjects with normal blood pressure response to exercise [NBPRE]. Ultrasound-measured carotid artery intima-media thickness [cIMT] was used as an index for atherosclerosis and plasma C-reactive protein [CRP] was measured as a marker for systemic inflammation. Despite similar levels of traditional atherosclerotic risk factors in GI and GII, cIMT was higher in GI compared to GII [0.77 +/- 0.23 mm and 0.62 +/- 0.15 mm; respectively] and there was a positive correlation between cIMT and maximal systolic blood pressure during exercise [r=0.69, p<0.001]. The percentage of patients with increased cIMT was significantly higher in subjects of GI compared to subjects of GII. Plasma CRP was higher in GI compared to GII [1.62 +/- 0.88 mg/L and 0.92 +/- 0.41 mg/L; respectively] and there was a weak positive correlation between cIMT and CRP [r=0.42, p<0.05]. From this study it can be concluded that, even in the absence of standard risk factors for atherosclerosis, exaggerated blood pressure reactivity during physical exercise is associated with increased risk for carotid atherosclerosis in normotensive subjects. Inflammatory reaction may have, even in part, a role in this increased risk

Insulin resistance and reduced nocturnal fall of blood pressure as risk factors for atherosclerosis in salt sensitive hypertension

Recent studies reported that salt sensitive [SS] hypertensive models are more susceptible to atherosclerotic complications than non-salt sensitive [NSS], and some other studies showed that a link may exist between salt sensitivity, reduced nocturnal fall of blood pressure and insulin resistance. The aim of the present study was to confirm these findings and to study the possible role of insulin resistance and reduced nocturnal fall of blood pressure in the suspected increase of atherosclerotic complications in SS hyertensive patients. This study was carried out on 26 patients with essential hypertension classified as 12 SS and 14 NSS. SS patients were at a significantly higher risk of being non-dippers than NSS [OR=11, 95% CI=1.35-114.75] and there was a significant negative correlation between salt sensitivity index [SSI] and nocturnal fall of blood pressure during high salt intake [r=-0.61, p<0.001]. Moreover, there was a significant positive correlation between SSI and both insulin resistance index [IRI] and insulin level during high salt intake [r=0.623, p<0.001 and r=0.621, p<0.001 respectively] and a significant negative correlation between nocturnal fall of blood pressure and both IRI and insulin level during high salt intake [r=0.517, p<0.01 and r=-0.486, p<0.05 respectively]. Nocturnal fall of blood pressure was preserved in SS patients during low salt intake and IRI and insulin level were significantly lower in SS patients during low salt intake compared to that during high salt intake [3.57 +/- 1.02 versus 5.64 +/- 1.67 and 15.92 +/- 3.82 micro lU/mL versus 23.5 +/- 5.99 micro lU/mL]. Carotid intima-media thickness [IMT] was significantly higher in SS patients compared to NSS [0.84 +/- 0.21 mm versus 0.65 +/- 0.16 mm] [p<0.05] and there was a significant positive correlation between carotid IMT and both IRI and insulin level [r=0.773, p<0.001 and r=0.700, p<0.001 respectively] and a significant negative correlation between carotid IMT and nocturnal fall of blood pressure [r=-0530, p<0.01]. It was concluded that insulin resistance, salt induced increase in blood pressure and reduced nocturnal fall of blood pressure are associated with each other in patients with essential hypertension. Insulin resistance and reduced nocturnal fall of blood pressure are closely related to atherosclerotic complications in hypertensive patients and are implicated, at least in part, in the increased atherosclerotic complications in SS patients. Dietary salt restriction can cause improvement of insulin sensitivity in SS patients and shift of circadian blood pressure rhythm from a non-dipper to dipper pattern

Role of nitric oxide in essential hypertension and its relationship to ventricular hypertrophy

Patients with essential hypertension exhibit blunted endothelium dependent vasodilator response, which is largely attributable to reduced bioavailability of nitric oxide [NO]. Therefore, this study was designed to estimate, more directly, nitric oxide production in patients with essential hypertension and to examine the possible association between NO and left ventrivular [LV] and vascular hypertrophy. The level of serum total nitrite and nitrate, the stable end products of NO oxidation, was measured in 40 hypertensive patients [group I] and 15 control subjects [group II]. Hypertensive patients were divided according to LV geometry into 21 patients with left ventricular hypertrophy [LVH] [group Ia] and 19 patients with normal LV geometry [group Ib]. Serum total nitrite and nitrate level was significantly lower in patients with essential hypertension compared to normal controls [25.07 +/- 8.78 micro mol/L verses 39.36 +/- 7.07 micro mol/L] [p<0.001]. It was significantly lower in patients with LVH compared to patients without LVH [20.50 +/- 8.07 micro mol/L versus 30.11 +/- 6.60 micro mol/L] [p<0.001]. There was a significant negative correlation between serum total nitrite and nitrate level and LVMI, IVS and PWT [p<0.001]. This study also showed a significant positive correlation between LVMI and carotid, femoral and aortic media to lumen [M/L] ratio [p<0.001]. Serum total nitrite and nitrate level was significantly lower in patients with higher M/L ratio and there was a significant negative correlation between serum total nitrite and nitrate level and carotid, femoral and aortic M/L ratio [p<0.01, p<0.001 and p<0.05 respectively]. It was concluded that NO level is reduced in patients with essential hypertension and that this reduced level has a role in the pathogenesis of left ventricular and vascular hy[ertrophy in patients with essential hyptertension