Massimo Puato

Blood pressure and atherogenic lipoprotein profiles of fish-diet and vegetarian villagers in Tanzania: the Lugalawa study

BACKGROUND There is evidence that populations with a high intake of fish, and specifically fish oils, are at reduced risk of cardiovascular disease. To explore the effect of fish intake, we compared two groups of Bantu villagers in Tanzania; one group live on the shores of Lake Nyasa and their diet includes large amounts of freshwater fish; the other group live in the nearby hills and have a vegetarian diet. METHODS We carried out a cross-sectional study of 622 fish-consuming villagers and 686 vegetarian villagers. 618 (99.4%) and 645 (94.0%), respectively, agreed to take part. Anthropometric and self-reported medical history data were collected by one local physician and a medical assistant, who also measured blood pressure and took blood samples for measurement of plasma lipids. A dietary questionnaire was administered to 25 families (about 15% of the study population) in each village. FINDINGS After adjustment for age, sex, and alcohol intake the fish-consuming group had lower mean blood pressure than the vegetarian group (123/72 vs 133/76 mm Hg, p < 0.001). The frequencies of definite and borderline hypertension (by WHO criteria) were lower in the fish-consuming than in the vegetarian group (2.8 vs 16.4%; 9.7 vs 22.3%, respectively). Plasma concentrations of total cholesterol (mean 3.53 [SD 1.04] vs 4.10 [1.04] mmol/L), triglycerides (0.92 [0.64] vs 1.31 [0.64] mmol/L), and lipoprotein(a) (201 [213] vs 321 [212] mg/L), were all lower (p < 0.0001) in the fish-consuming group than in the vegetarian group. The proportions of n-3 polyunsaturated fatty acids in plasma lipids were higher (p < 0.0001) in the fish-consuming group than in the vegetarian group (eicosapentaenoic acid 2.3 [1.3] vs 0.7 [0.2]%; docosapentaenoic acid 1.1 [0.4] vs 0.6 [0.3]%; docosahexaenoic acid 5.7 [1.6] vs 1.5 [1.1]%). INTERPRETATION In these villagers, consumption of freshwater fish (300-600 g daily) was associated with raised plasma concentrations of n-3 polyunsaturated fatty acids, lower blood pressure, and lower plasma lipid concentrations.

Assessment of flow-mediated dilation reproducibility: a nationwide multicenter study

Objective: Impaired flow-mediated dilation (FMD) is associated with cardiovascular risk factors and provides prognostic information. Despite the noninvasive nature of this technique, a major limitation to its widespread use is low reproducibility. The aim of this study was to evaluate impact of methodological standardization among different investigation sites on brachial artery FMD reproducibility. Methods: Seven Italian centers recruited 135 healthy volunteers, aged 20–60 years. FMD was assessed by high-resolution ultrasound equipped with a stereotactic probe-holding device. Certified sonographers recorded brachial artery scans at baseline (day 1a), 1 h after (day 1b), and 1 month later (day 30). Endothelium-independent vasodilation (EIVD) to sublingual glyceril-trinitrate was recorded at day 1 and day 30. FMD and EIVD were blindly evaluated at the coordinating center by an automated edge detection system. The intra-session (day 1a versus 1b) and inter-session (day 1a versus 30) coefficients of variation were calculated. Results: FMD was not significantly (P = 0.91) different at day 1a, day 1b and day 30 (6.52 ± 2.9, 6.42 ± 3.1, 6.57 ± 2.8%, respectively). The FMD intra-session coefficient of variation was 9.9 ± 8.4% (from 7.6 to 11.9% across centers). The FMD inter-session coefficient of variation was 12.9 ± 11.6% (from 11.6 to 16.1% across centers). Inter-session coefficient of variation for EIDV was 19.7 ± 16.8%. Conclusions: This study shows a homogeneous coefficient of variation for FMD among different centers. The inter-session coefficient of variation was similar to the intra-session coefficient of variation, representing the intrinsic FMD variability. We demonstrate for the first time that rigorous and standardized procedure may provide reproducible FMD assessment to study endothelial function in multicenter clinical trials.

Increase in Carotid Intima-Media Thickness in Grade I Hypertensive Subjects. White-Coat Versus Sustained Hypertension

We studied 74 never-treated grade I hypertensive subjects aged 18 to 45 years and 20 normotensive control subjects to define the rate of increase in carotid intima-media thickness (IMT) and the potential role played by the various risk factors. IMT was assessed as mean IMT and as maximum IMT in the right and left common carotid artery, carotid bulb, and internal carotid artery at baseline and at the 5-year follow-up. In grade I hypertensive subjects, both mean IMT and mean of maximum IMT were significantly higher compared with baseline values. Compared with normotensive subjects, both mean IMT and maximum IMT increased significantly (at least P<0.01) in each carotid artery segment. The increase in cumulative IMT was 3.4-fold for mean IMT and 3.2-fold for mean of maximum IMT. Levels of mean arterial pressure at 24-hour monitoring and total serum cholesterol were factors potentially linked to the increment in mean IMT and mean of maximum IMT. Age was also relevant for the increment in mean of maximum IMT, whereas body mass index played some role in the increment of mean IMT. During the follow-up, mean IMT and mean of maximum IMT increased to a greater degree in white-coat hypertensive subjects (n=35) and sustained hypertensive subjects (n=39) than in normotensive control subjects. No differences were found between white-coat hypertensive subjects and sustained hypertensive subjects for both mean IMT and maximum IMT. Levels of mean arterial pressure at 24-hour monitoring affected the increment in IMT in both white-coat hypertensive subjects and sustained hypertensive subjects. In conclusion, our findings indicate that carotid IMT is greater and grows faster in white-coat hypertensive subjects than in normotensive subjects without significant differences with sustained hypertensive patients.

Effects of a traditional lifestyle on the cardiovascular risk profile: the Amondava population of the Brazilian Amazon. Comparison with matched African, Italian and Polish populations.

OBJECTIVE To determine the relationships between lifestyle and cardiovascular risk factors among the Brazilian Amondava, one of the worlds most isolated populations. DESIGN Cross-sectional, population-based study. Four age- and sex-matched samples from Brazil Africa, Italy and Poland, representing different levels of modernization, were compared. Body weight, height, blood pressure, serum cholesterol and glycaemia were measured, and a standard questionnaire administered. Data concerning dietary habits and physical activity were collected. A personal socio-economic score was calculated, on the basis of type of economy, level of formal education, type of occupation, type of habitat, availability of piped water and electricity, main source of income, housing conditions, availability of radio, television or personal computer, knowledge of a second language, and organized health facilities. SETTING Primary epidemiological screening, at an institution. RESULTS Among the Amondava blood pressure was always <140/90 mm Hg, it did not increase with age and was not correlated with any other variable; 46.6% of subjects had systolic blood pressure <100 mm Hg. Blood pressure among the Amondava (109.6+/-11.1/69.5+/-6.4 mm Hg) was on average lower (P<0.0001) than in all other samples. Among the Amondava, the concentration of total cholesterol was always <200 mg/dl, i.e. similar to that of Africans whose diet included large amounts of vegetable foodstuffs; 90% had glycaemia (<80 mg/dl), and their mean value was the lowest (55.1+/-14.9 mg/dl) of all the groups. CONCLUSIONS In addition to a possible genetic predisposition not analysed in this study, a traditional lifestyle (no contact with civilization, diet based on complex carbohydrates and vegetables, high energy expenditure) may protect against the development of hypertension, hypercholesterolaemia, and diabetes.

Fish-Rich Diet, Leptin, and Body Mass

Background—Leptin has been implicated in cardiovascular disease. A diet rich in fish has been associated with decreased cardiac and vascular risk. Methods and Results—We examined the relationship between diet and leptin in 2 related homogeneous African tribal populations of Tanzania. One tribe consumes freshwater fish as their main diet component (n=279), and the other tribe consumes a primarily vegetarian diet (n=329). In multivariate analysis, plasma leptin levels were associated with type of diet (F=14.3, P <0.001), independent of age, body mass index, body fat, alcohol consumption, or insulin. Both male (2.5±2 [fish diet] versus 11.2±2.4 [vegetarian diet] ng/mL, P =0.017) and female (5.0±1.9 [fish diet] versus 11.8±1.4 [vegetarian diet] ng/mL, P =0.007) fish eaters had lower plasma leptin levels than did their vegetable diet counterparts, even though body mass index values were virtually identical. Conclusions—A diet rich in fish is associated with lower plasma leptin, independent of body fat. These findings may have implications for understanding the reduced cardiovascular risk in subjects on a high-fish diet.

Atorvastatin Reduces Macrophage Accumulation in Atherosclerotic Plaques A Comparison of a Nonstatin-Based Regimen in Patients Undergoing Carotid Endarterectomy

Background and Purpose— The object of our study was to compare the effect of high-dose vs low-dose atorvastatin vs nonstatin-based treatment (cholestyramine plus sitosterol) on cell composition of carotid plaque. Methods— We recruited 60 hypercholesterolemic patients (total cholesterol, 5.83-7.64 mmol/L) eligible for carotid endarterectomy. Three months before surgery, patients were randomized into 3 groups (n=20) receiving atorvastatin 10 mg/day (AT-10) or atorvastatin 80 mg/day (AT-80) or cholestyramine 8 g/day plus sitosterol 2.5 g/day. Analysis of cell composition was performed on endarterectomy specimens. Results— The 3 treatments resulted in a significant reduction of total cholesterol and low-density lipoprotein cholesterol (LDL-C), although the decrease in total cholesterol and LDL-C was of smaller magnitude in the cholestyramine plus sitosterol group. The 3 regimens did not influence the levels of inflammatory markers (including high-sensitivity C-reactive protein). Macrophage content was significantly lower in the AT-10 group plaques compared to the cholestyramine plus sitosterol group. It was further reduced in the AT-80 group plaques. These differences were no longer significant after adjustment for changes in LDL-C. No difference in lymphocyte number was observed among treatments, whereas the content of smooth muscle cells was higher in the AT- 80 group. An inverse association was observed between LDL-C changes in the 3 groups and macrophage content in the plaques. Conclusions— Short-term treatment with high-dose statin is superior to a nonstatin lipid-lowering regimen in reducing the macrophage cell content within atherosclerotic lesions, but this effect was determined by the degree of LDL-C-lowering.

Fish Intake, Independent of Apo(a) Size, Accounts for Lower Plasma Lipoprotein(a) Levels in Bantu Fishermen of Tanzania The Lugalawa Study

Plasma lipoprotein(a) [Lp(a)] levels are largely genetically determined by sequences linked to the gene encoding apolipoprotein(a) [apo(a)], the distinct protein component of Lp(a). Apo(a) is highly polymorphic in length due to variation in the numbers of a sequence encoding the apo(a) kringle 4 domain, and plasma levels of Lp(a) are inversely correlated with apo(a) size. In 2 racially homogeneous Bantu populations from Tanzania differing in their dietary habits, we found that median plasma levels of Lp(a) were 48% lower in those living on a fish diet than in those living on a vegetarian diet. Considering the relationship between apo(a) size and Lp(a) plasma concentration, we have extensively evaluated apo(a) isoform distribution in the 2 populations to determine the impact of apo(a) size in the determination of Lp(a) values. The majority of individuals (82% of the fishermen and 80% of the vegetarians) had 2 expressed apo(a) alleles. Additionally, the fishermen had a high frequency of large apo(a) isoforms, whereas a higher frequency of small isoforms was found in the vegetarians. When subjects from the 2 groups were matched for apo(a) phenotype, the median Lp(a) value was 40% lower in Bantus on the fish diet than in those on the vegetarian diet. A significant inverse relationship was also found between plasma n-3 polyunsaturated fatty acids and Lp(a) levels (r=-0.24, P=0.01). The results of this study are consistent with the concept that a diet rich in n-3 polyunsaturated fatty acids, and not genetic differences, is responsible for the lower plasma levels of Lp(a) in the fish-eating Bantus and strongly suggest that a sustained fish-based diet is able to lower plasma levels of Lp(a).

Absence of vascular remodelling in a high angiotensin-II state (Bartter's and Gitelman's syndromes): implications for angiotensin II signalling pathways

BACKGROUND Angiotensin II (Ang II) is a powerful proinflammatory cytokine and growth factor that activates NF-kappaB, as well as NAD(P)H oxidase, and thus is a key factor for the induction and progression of cardiovascular diseases. Our previous studies have shown high Ang II and high blood pressure-driven proatherogenic remodelling in an animal model. To further explore Ang II in proatherogenic vascular remodelling independent of blood pressure, we used Bartters/Gitelmans syndrome (BS/GS) patients given their elevated plasma Ang II, yet normo/hypotension, because extensive mechanistic studies in these patients suggest they are a good model to explore Ang II-mediated signalling. METHODS The study evaluated BS/GS patients for nitric oxide-dependent (FMD) and -independent vasodilation and intima-media thickness (IMT) of the carotid arteries compared with healthy subjects and essential hypertensive patients. RESULTS The results showed the absence of IMT growth in BS/GS patients as cumulative mean-IMT and mean maximum-IMT levels in BS/GS did not differ from normotensives: 0.58 +/- 0.09 mm versus 0.60 +/- 0.09 and 0.67 +/- 0.09 versus 0.70 +/- 0.13 respectively, P = ns, but were significantly lower compared with hypertensive patients: 0.69 +/- 0.13, P < 0.046 and 0.85 +/- 0.19, P < 0.018, respectively. FMD was increased in BS/GS versus hypertensives or normotensive controls (10.8 +/- 2.7% versus 6.5 +/- 2.3 and 8.7 +/- 1.9, P < 0.002 respectively) while endothelium-independent dilation did not differ (10.2 +/- 3.6% versus 7.2 +/- 1.9 and 8.2 +/- 3.3, P = ns) between groups. CONCLUSIONS Our study in BS/GS provides to our knowledge the first clinical data that point to a direct proatherogenic role for Ang II. However, because the data are derived from findings in BS/GS and therefore are indirect, further studies in this and other models using more direct approaches should be pursued to demonstrate a direct proatherogenic effect of Ang II as well as further studies on Ang II type 2 receptor (AT2R) signalling that the spectrum of findings of this and other studies indicate as involved in the lack of vascular remodelling.

Blood pressure, serum cholesterol and nutritional state in Tanzania and in the Amazon: comparison with an Italian population.

Objective To confirm that westernization of dietary habits represents a stimulus for the expression of cardiovascular risk. Design Three representative age- and sex-matched samples of general populations of three continents were compared cross-sectionally by analysis of variance. Participants In total 1110 subjects aged 22–89 years, divided into three groups (370 from Tanzania and Uganda, 370 from the Amazonian region of Brazil, and 370 from northern Italy; 111 men and 259 women in each group). Results The blood pressure of Africans eating a low-salt ‘fish and vegetable’ diet was lower than those of Brazilians, whose diet was based on cereals and meat, and highly urbanized Italians. The systolic blood pressure was correlated to the body mass index for all three populations, but with age only for the Brazilians and Italians. The total cholesterol level and body mass index, both of which are low among Africans, increased progressively with increasing economic level. Conclusions Transition from a rural to an urbanized lifestyle is accompanied by a rise in the main cardiovascular risk factors; the present data also show that environmental rather than racial factors have a crucial impact on the risk pattern of populations.

Specific Cellular Features of Atheroma Associated With Development of Neointima After Carotid Endarterectomy The Carotid Atherosclerosis and Restenosis Study

BACKGROUND The purpose of this study was to investigate whether some cellular and molecular features of tissue retrieved at carotid endarterectomy are associated with the extent of neointima formation at ultrasound follow-up. METHODS AND RESULTS One hundred fifty patients were studied. Endarterectomy specimens were tested by immunocytochemistry with the use of (1) monoclonal antibodies that identify smooth muscle cells (SMCs) and fetal-type SMCs on the basis of smooth muscle and nonmuscle myosin content, (2) the anti-macrophage HAM 56, and (3) the anti-lymphocyte CD45RO. The maximum intima-media thickness (M-IMT) of the revascularized vessel was assessed by the use of B-mode ultrasonography 6 months after surgery. The M-IMT values were related positively to the number of SMCs (r=0.534, P<0.0005) and negatively to that of macrophages and lymphocytes (r=-0.428, P<0.0005, and -0.538, P=0.001, respectively). Patients were classified as class 1 (M-IMT </=1.0 mm), class 2 (1. 01.3 mm). An abundance of SMCs, mostly of fetal type, was found in the plaque of class 3 patients, whereas lesions from class 1 patients were rich in macrophages and lymphocytes. In the multivariate analysis, factors related to M-IMT were the number of SMCs and the percentage of fetal-type SMCs present in the plaque. CONCLUSIONS Although the classic risk factors did not play a role, an abundance of SMCs and a scarcity of macrophages characterized the primary lesion of patients in whom neointima developed after surgery. In patients in whom neointima did not develop, lesions were rich in macrophages and lymphocytes. This approach can be useful in defining patients at risk of restenosis.