Prevalence and Correlates of Anemia and Uncontrolled Anemia in Chronic Hemodialysis Patients – The Campania Dialysis Registry

Background

This study investigated prevalence and correlates of anemia and uncontrolled anemia in chronic hemodialysis patients.

Methods

A cross-sectional analysis was performed on registry data for 2,746 chronic (<6 months) hemodialysis patients aged 25–84. Data collection included years of dialysis, hours of dialysis/wk, disease causing hemodialysis, body mass index (BMI), erythropoietin (EPO) treatment, hemoglobin, markers of viral hepatitis, serum albumin, calcium, and phosphorus.

Results

Prevalence was 88.7% for anemia (hemoglobin <11 g/100 mL and EPO treatment at any Hb level), 39.4% for uncontrolled anemia (hemoglobin<11 g/100 mL). Gender, years of dialysis, hereditary cystic kidney disease (HCKD), and low BMI (<24 kg/m2) were independent correlates of anemia (P<0.001). Gender, HCKD, low BMI, serum albumin and calcium were independent correlates of uncontrolled anemia (P<0.05). An interaction was found between age (not correlated with anemia and uncontrolled anemia) and the association of gender with uncontrolled anemia (P<0.05). EPO doses were higher in patients with high prevalence of uncontrolled anemia than in patients with low prevalence (i.e., women vs men, other diseases vs HCKD, low vs not-low BMI, P<0.01). Gender, years of dialysis, HCKD, BMI, serum albumin, and calcium were independent correlates of the hemoglobin/EPO dose ratio in patients on EPO treatment (P<0.05).

Conclusion

Anemia and uncontrolled anemia are more frequent in hemodialysis patients with short-term dialysis, diseases other than HCKD, low BMI, and female gender. Gender effect was lower in elderly patients. Uncontrolled anemia was also associated with low serum albumin and calcium, suggesting that these parameters are indices of EPO resistance.

Difference in carotid artery elasticity in subjects with different brachial artery kinetic of vasodilatation

Increased carotid stiffness and impaired brachial artery flow-mediated dilatation (FMD) associate with cardiovascular events. We have previously reported three FMD patterns based on the time of maximal dilatation. The aim of the present study was to verify whether different FMD patterns associate with carotid artery stiffness. In all, 133 subjects were enrolled. All participants underwent complete clinical examination, blood sampling and ultrasound study. FMD was used as a measure of endothelial function. Based on the maximal brachial artery FMD, subjects were divided into Early dilators (peak FMD at 50 s), Late dilators (peak FMD over 50 s) and No dilators. Echo-Doppler evaluation of carotid arteries was performed in order to calculate elastic indexes (strain, β-stiffness index and distensibility). In all, 64 subjects were classified as Early FMD, 36 as Late FMD and 33 as No dilators. Age, gender and cardiovascular risk factors were comparable among three groups. Early FMD had higher values of strain compared with both Late and no Dilators (P<0.001). Furthermore, Early dilators showed a significantly lower stiffness and higher distensibility compared with Late and No dilators. No significant differences between Late FMD and No Dilators were detected. Our results demonstrate that common carotid artery elasticity indexes significantly differ among Early, Late and No dilators. Subjects with delayed or absent brachial artery dilatation have stiffer common carotid arteries compared with subjects with early dilatation. In conclusion, our research suggests that the assessment of the kinetics of FMD in a clinical setting might represent a useful screening tool to improve the cardiovascular risk stratification.

Blood urea impairs brachial artery flow mediated dilation

AIM

Urea, the main product of protein catabolism, is a biochemical marker of renal function. Though it is known that serum urea impairs vascular health, the relationship between its concentration and vascular reactivity in vivo has not been explored. Our study was undertaken to investigate possible association between serum urea and endothelial function in subjects without chronic kidney disease (CKD).

METHODS

Eighty free-living subjects with serum creatinine ≤1 mg/dL and without CKD were enrolled for the present study. Serum analyses and evaluation of endothelial function were performed in all subjects. Endothelial function was measured using the flow-mediated dilation (FMD) technique. Simple and multiple regression analyses were used to test the association between FMD and considered variables.

RESULTS

In correlation analyses FMD was found directly associated with HDL cholesterol (r=0.21; P=0.05) and eGFR (r=0.25; P=0.02) and inversely associated with age (r=-0.26; P=0.02), serum urea (r=-0.37; P<0.01), serum creatinine (r=-0.31; P<0.01) and brachial artery baseline diameter (r=-0.41; P<0.01). In multiple regression analysis only baseline artery diameter and serum urea predicted FMD; age, gender and cardiovascular risk factors did not relate with FMD.

CONCLUSION

Our study demonstrates the association between serum urea and FMD, suggesting that the accumulation of waste products of protein metabolism may impair vascular health in subjects without CKD.

Time course analysis of brachial artery flow mediated dilatation in subjects with gingival inflammation

AIM

Several investigations report an inverse association between periodontal disease and endothelial function measured by brachial artery Flow-Mediated-Dilatation (FMD) technique. These studies examined endothelial function by using the traditional approach to FMD calculation, that is from diameters assessed at 60 seconds after deflation. Nevertheless, possible relationship between gingival inflammation and endothelial dysfunction observed over this temporal threshold remains still unexplored. The purpose of our study was to explore the relationship between gingival inflammation and endothelial function, by considering the time course of brachial FMD.

METHODS

Forty-six free-living white subjects, participating in a cardiovascular disease prevention campaign, were enrolled. FMD was measured at 60s and at 2 and 3 min after forearm ischemia. Maximal FMD was calculated (Peak FMD), for each patient. Gingival Index (GI) was evaluated as measure of gingival inflammation.

RESULTS

In univariate analyses, GI was associated with both FMD at 60 sec (r=-0.30, P=0.038) and Peak FMD (r=-0.41, P=0.004). In multiple regression analyses including GI, age, gender, and known risk factors for atherosclerosis, only GI and age were independently and inversely associated with Peak FMD and FMD at 60 s, but this association was stronger with Peak FMD. Moreover, when we divided subjects on the basis of GI value, patients with GI > 1 presented lower Peak FMD and higher prevalence of absent FMD.

CONCLUSION

The present study extends previous observations about the negative effects of periodontal disease on endothelial function, highlighting the importance of the evaluation of time course of vascular reactivity.

Markers of insulin resistance and carotid atherosclerosis. A comparison of the homeostasis model assessment and triglyceride glucose index

AIMS

The present investigation was designed to test the association between carotid atherosclerosis and two simple markers of insulin resistance, i.e. HOMA-Index and TyG-Index.

MATERIALS AND METHODS

The study was performed in two different cohorts. In the first cohort, 330 individuals were enrolled. Blood pressure, lipids, glucose, waist and cigarette smoking were evaluated. HOMA-IR and TyG-Index were calculated as markers of prevalent hepatic and muscular insulin resistance respectively. Carotid atherosclerosis was assessed by Doppler ultrasonography. The association between cardiovascular risk factors, markers of insulin resistance and carotid atherosclerosis was assessed by multiple logistic regression analyses. In the second cohort, limited to the evaluation of TyG-Index, 1432 subjects were studied.

RESULTS

In the first cohort, TyG-Index was significantly associated with carotid atherosclerosis in a model including age, sex, diabetes, cigarette smoking and LDL cholesterol, while HOMA-IR was not. When components of metabolic syndrome were added to the model as dichotomous variables (absent/present), TyG-Index retained its predictive power. The same result was obtained when the metabolic syndrome was added to the model (absence/presence). The association between TyG-Index and carotid atherosclerosis was confirmed in the second cohort.

CONCLUSIONS

The present findings suggest that TyG-Index is better associated with carotid atherosclerosis than HOMA-IR.

Metabolic syndrome in subjects at high risk for type 2 diabetes: the genetic, physiopathology and evolution of type 2 diabetes (GENFIEV) study

BACKGROUND AND AIM

We evaluated the relationship between insulin resistance (IR) and insulin secretion with the metabolic syndrome (MS) in 885 subjects (377 men/508 women, age 49±11 years, BMI 29±5.2kgm(-2)) at risk of diabetes enrolled in the genetics, pathophysiology and evolution of type 2 diabetes (GENFIEV) study.

METHODS AND RESULTS

All subjects underwent a 75-g oral glucose tolerance test (OGTT) for the estimation of plasma levels of glucose and C-peptide, as well as fasting insulin and lipid profile. IR was arbitrarily defined as HOMA-IR value above the 75th centile of normal glucose tolerance (NGT) subjects. Overall MS prevalence (National Cholesterol Treatment Panel-Adult Treatment Panel (NCEP-ATPIII) criteria) was 33%, 19% in subjects with NGT, 42% in impaired fasting glucose (IFG), 34% in impaired glucose tolerance (IGT), 74% in IFG+IGT subjects, and 56% in newly diagnosed diabetic patients. Prevalence was slightly higher with IDF criteria. MS prevalence was >50% in subjects with 2h glucose >7.8mmoll(-1), independently of fasting plasma glucose. IR prevalence was higher in subjects with MS than in those without (63% vs. 23%; p<0.0001) and increased from 54% to 73% and 88% in the presence of three, four or five traits, respectively. IR occurred in 42% of subjects with non-diabetic alterations of glucose homeostasis, being the highest in those with IFG+IGT (IFG+IGT 53%, IFG 45%, IGT 38%; p<0.0001). Individuals with MS were more IR irrespective of glucose tolerance (p<0.0001) with no difference in insulinogenic index. Hypertriglyceridaemia (OR: 3.38; Confidence Interval, CI: 2.294.99), abdominal obesity (3.26; CI: 2.18-4.89), hyperglycaemia (3.02; CI: 1.80-5.07) and hypertension (1.69; CI: 1.12-2.55) were all associated with IR.

CONCLUSIONS

These results show that in subjects with altered glucose tolerance (in particular IFG+IGT) MS prevalence is high and is generally associated to IR. Some combinations of traits of MS may significantly contribute to identify subjects with IR.

Primary hyperlipidemias in children: effect of plant sterol supplementation on plasma lipids and markers of cholesterol synthesis and absorption

Plant sterols lower serum cholesterol concentration. Available data have confirmed the lipid-lowering efficacy in adults, while there is a relative dearth of data in children and almost exclusively restricted to subjects with familial hypercholesterolemia (FH). Aim of the present study was to evaluate the efficacy, tolerability and safety of plant sterol supplementation in children with different forms of primary hyperlipidemias. The effect of plant sterol consumption on plasma lipids was evaluated in 32 children with heterozygous FH, 13 children with Familial Combined Hyperlipidemia (FCH) and 13 children with Undefined Hypercholesterolemia (UH) in a 12-week open-label intervention study using plant sterol-enriched yoghurt. Plasma lipids and apolipoproteins were measured by routine methods. Markers of cholesterol synthesis (lathosterol) and absorption (campesterol and sitosterol) were measured by GC-MS. Tolerability and adherence to recommended regimen was very high. A significant reduction was observed in LDL-cholesterol in the three groups (10.7, 14.2 and 16.0% in FH, FCH and UH, respectively). Lathosterol concentrations were unchanged, reflecting a lack of increased synthesis of cholesterol. Of the two absorption markers, only sitosterol showed a slight but significant increase. Daily consumption of plant sterol dairy products favorably changes lipid profile by reducing LDL-cholesterol. To our knowledge, this is the first report of the use of plant sterols-enriched foods in treating children with primary hyperlipidemia such as FCH and UH, likely to be the most frequent form also in the young age in the western populations.

Plasma and blood viscosity in metabolic syndrome

BACKGROUND AND AIM

The relationship between metabolic syndrome (MS) and blood and plasma viscosity has been scarcely investigated. In the present study we have evaluated the difference in blood and plasma viscosity between subjects with and without MS, in order to verify whether viscosity measurement can add more information on the overall cardiovascular risk connected with the presence of the MS.

METHODS AND RESULTS

Two hundred and sixty nine women and 520 men have been enrolled. Blood and plasma viscosity have been measured with a cone-plate viscometer equipped with a cp-40 spindle. MS has been defined according to the third report of the National Cholesterol Education Program, Adult Treatment Panel III. Eighty four women and 154 men fulfilled the criteria for MS. Hematocrit adjusted blood viscosity was higher in subjects with MS compared to those without the syndrome, both in males (shear rate 225 s(-1): 4.60+/-0.38 vs. 4.52+/-0.33 cP, p<0.01) and females (4.57+/-0.28 vs. 4.46+/-0.31 P, p<0.01). Blood viscosity was correlated with all components of MS but glucose, and after adjustment for them the difference between subjects with or without MS was completely abolished. Plasma viscosity was significantly higher only in females with MS.

CONCLUSIONS

These data demonstrate that blood viscosity is increased in subjects with MS, but the increase seems to depend on the metabolic alterations of the syndrome. The independent contribution of the rise in blood viscosity to the cardiovascular risk connected with the presence of MS seems therefore negligible. The increased plasma viscosity in females with MS needs further clarification.

Stromelysin gene promoter polymorphism and common carotid geometry in diabetic subjects

AIM

Stromelysin (MMP3), through its action on collagen and other matrix metalloproteinases, influences arterial wall remodeling. In healthy subjects, the 5A/6A polymorphism located in the promoter of the MMP3 gene is associated with common carotid remodeling, 6A/6A subjects having increased arterial diameter, wall thickness (intima-media thickness, IMT) and decreased wall shear stress (WSS). In the present study, we have investigated the influence of the 5A/6A polymorphism on common carotid remodeling in subjects with diabetes mellitus.

METHODS

Diabetic subjects (N.=136) and age-matched healthy male controls (N.=101) have been studied. Common carotid diameter, IMT and flow velocity have been measured by echo-Doppler. Blood viscosity has been measured by a cone/plate viscometer. WSS has been calculated.

RESULTS

Diabetic patients had increased common carotid diameter, IMT, and decreased flow velocity and WSS (all P<0.05), compared with controls. In controls, subjects homozygous for the 6A allele had increased diameter, IMT and decreased WSS. In diabetics, no difference was observed in vascular parameters among the three genotypes.

CONCLUSION

The 5A/6A polymorphism of the MMP3 gene influences arterial remodeling of the common carotid artery in healthy subjects, but not in patients with diabetes mellitus. Therefore, the significance of the 5A/6A polymorphism as a marker of risk in this high cardiovascular risk population seems to be somehow blunted.

Beta-sitosterolaemia: a new nonsense mutation in the ABCG5 gene

BACKGROUND

Sitosterolaemia is a rare autosomal recessive disorder characterised by elevated plasma levels of plant sterols and cholesterol. Sitosterolaemia is caused by gene mutations in either of two ATP-binding cassette (ABC) half transporters, ABCG5 and ABCG8. The plasma sterol profile and genetic analysis of a 10-year-old girl who had tuberous xanthomas is the subject of this report.

MATERIALS AND METHODS

Genomic DNA was isolated from white blood cells from the proband, her family and a control group of healthy people. All exons of ABCG5 and ABCG8 were sequenced. Plasma cholesterol and triglycerides were measured by routine methods. All other plasma sterols were measured by Gas Chromatography coupled to Mass Spectrometry.

RESULTS

The proband was found to be homozygous for a single nucleotide mutation in exon 10 of the ABCG5 gene, consisting of a C to T transition at nucleotide 1336 of the coding sequence, which results in the premature termination of the ABCG5 protein at amino acid 446 (Arg446X). Her mother and brother were also homozygous for the same mutation and all had elevated plasma beta-sitosterol levels. The father was heterozygous and showed normal beta-sitosterol levels. This mutation was not found in healthy normolipidaemic subjects.

CONCLUSIONS

We describe a novel nonsense mutation in exon 10 of the ABCG5 gene in a 10-year-old girl showing clinical and biochemical features of sitosterolaemia. This family study broadens the spectrum of the ABCG5/ABCG8 mutations causing sitosterolaemia and helps highlight the correlations between such gene mutations, biochemical phenotype and the development of cardiovascular disease.

Flow-mediated vasodilatation of the brachial artery and intima-media thickness of carotid artery in never-treated subjects

AIM

Data on the association between brachial artery flow-mediated dilatation (FMD) and common carotid intima-media thickness (IMT) are contrasting. The present study investigated the relationship between FMD and IMT and carotid atherosclerosis in never treated subjects.

METHODS

Seventy-seven subjects were investigated: 46 had no coronary heart disease (CHD) risk factors, 21 had only one, and 10 had more than one risk factor. IMT of the common carotid was measured by ultrasonography and FMD was evaluated according to standardized methods.

RESULTS

IMT increased with increasing number of risk factors (0.66+/-0.12, 0.69+/-0.12 and 0.8+/-0.17 mm, respectively, ANOVA P<0.05). FMD decreased with increasing number of risk factors (10.44+/-5.2, 6.52+/-7.11 and 7.35+/-4.42%, respectively, P<0.05). Endothelium-independent vasodilatation was similar in the 3 groups. IMT and FMD did not correlate neither in subjects without risk factors (r=-0.151, P=0.3), nor in those with 1 (r=-0.196, P=0.4) or with 2 or more risk factors (r=-0.387, P=0.2), while in the group as a whole the correlation was borderline significant (r=-0.217, P=0.058). Eleven subjects had carotid atherosclerosis and higher values of IMT, but not reduced FMD. In multiple regression analysis, diabetes and IMT, but not FMD, were associated with carotid atherosclerosis.

CONCLUSIONS

The present findings indicate that, in never treated subjects, FMD is not strictly associated with IMT or atherosclerosis of the carotid arteries.

Effects of iodinated contrast media on common carotid and brachial artery blood flow and wall shear stress

The aim of our study was to evaluate the effect of the intravenous contrast media iomeprol on wall shear stress, blood flow and vascular parameters in the common carotid and brachial artery. Thirty outpatients undergoing thoracic or abdominal spiral CT scans were studied. The internal diameter and flow velocity of the common carotid and brachial artery were evaluated by ultrasound, and blood viscosity was measured before and after low osmolality iomeprol (Iomeron 350) injection. The wall shear stress, blood flow and pulsatility index were calculated. To test the differences between groups, the Wilcoxon rank test and Mann Whitney U test were applied. Blood viscosity decreased slightly, but significantly after contrast media (4.6+/-0.7 vs. 4.5+/-0.7 mPa.s, P = 0.02). Contrarily, blood flow and wall shear stress did not change in the common carotid artery, but significantly decreased in the brachial artery (0.9+/-0.4 vs. 0.6+/-0.3 ml/s, P < 0.0001, and 41.5+/-13.9 vs. 35.3+/-11.0 dynes/cm2, P < 0.002, respectively), whereas the pulsatility index significantly increased in the brachial artery (5.0+/-3.3 vs. 7.5+/-5.3, P < 0.001). Iomeprol injection causes blood flow and wall shear stress reduction of the brachial artery; the rise in the pulsatility index suggests an increase in peripheral vascular resistance. Further investigation is needed to evaluate whether these modifications can be clinically relevant.

A multiplex PCR-based DNA assay for the detection of paraoxonase gene cluster polymorphisms

Paraoxonase (PON) is a high-density lipoprotein (HDL) associated protein which is supposed to protect low-density lipoprotein (LDL) against oxidation and to play a role in the development of atherosclerosis. Interindividual variability in serum PON activity is attributable to common variants in components of the PON gene cluster on chromosome 7. We describe experimental conditions that permit the simultaneous determination of three common PON polymorphisms (PON1-192, PON1-55 and PON2-311) that are tightly associated with an increased risk of atherosclerosis. We used a multiplex PCR-based DNA assay using mismatch primers that introduce a unique recognition site for the endonuclease HinfI in the PCR products in case of presence of the R allele of PON 1-192, of the L allele of PON1-55 and of the S allele of PON2-311. The restriction analysis with HinfI allows to identify an electrophoretic band pattern which is specific for the combination of the three polymorphisms. This technique could be applied in the association studies aimed at assessing the role of PON and their polymorphisms in many clinical settings. In a preliminary study on a small population sample from south Italy about 10% of chromosomes exhibited the presumed risk-related haplotype R(192)/L(55)/S(311).

Comparison of endothelial function evaluated by strain gauge plethysmography and brachial artery ultrasound

Strain gauge plethysmography and brachial artery ultrasound are widely used to study endothelial function. No data on correlation between these two procedures are reported. The present study compared these two methods and investigated the correlation between vasodilation and brachial wall shear stress. In six healthy subjects and ten patients with hypertension or obesity, strain gauge plethysmography was performed in resting conditions and after infusion of 7.5,15 and 30 microg/min of acetylcholine, and brachial artery ultrasound in resting conditions and after 5 min hand ischemia. Wall shear stress was calculated as: blood viscosity x blood velocity/internal diameter. Forearm blood flow following acetylcholine infusion increased more in healthy subjects than in patients with hypertension or obesity. In addition, brachial artery dilated more in the former group. Change in brachial artery diameter correlated with change in forearm blood flow, calculated as area under the curve of acetylcholine infusion (r=0.739, P<0.001). Wall shear stress was higher in healthy subjects (67.8+/-20.0 dynes/cm(2)) than in patients with either hypertension or obesity (39.2+/-16.7, P<0.001), and correlated with variations of diameter (r=0.796, P<0.0002), and marginally of blood flow (r=0.516, P<0.05). The present findings demonstrate that there is a high correlation between endothelial function evaluated by strain gauge plethysmography and brachial artery ultrasound. Wall shear stress correlates with brachial artery diameter change following hand ischemia, and marginally with blood flow change following acetylcholine infusion.

Association between wall shear stress and flow-mediated vasodilation in healthy men

Wall shear stress contributes to the endothelial production of vasoactive mediators, like nitric oxide (NO). Brachial artery vasodilation that follows increased blood flow is regulated by NO release. Aim of the present study was to investigate whether resting wall shear stress of the brachial artery is related to flow-mediated vasodilation (FMD) induced by forearm ischemia. Wall shear stress was calculated according to the following formula: Wall shear stress=Blood viscosity x Blood velocity/Internal diameter. FMD was calculated as percentage change of brachial artery diameter following forearm ischemia. Twenty-seven healthy male subjects were investigated. Peak wall shear stress and FMD were 37.3+/-12.8 dynes/cm(2) and 110.7+/-5.6%, respectively (mean+/-S.D.). In simple regression analyses, age was inversely associated with wall shear stress (r=48, P<0.01) and, marginally, with FMD (r=0.33, P=0.08). Wall shear stress and FMD were directly related (r=0.60, P<0.001). In multiple regression analysis, including wall shear stress, age, blood pressure, lipids, glucose and Body Mass Index as independent variables, wall shear stress was the only variable independently associated with FMD (standardized beta coefficient=0.690, P</=0.005). To avoid the influence of brachial artery size on FMD, the regression analysis was restricted to subjects with similar diameter (n=12). In these subjects wall shear stress continued to be significantly associated with FMD (r=0.69, P=0.01). Our results demonstrate a strong association between resting wall shear stress and FMD in the brachial artery in healthy men in vivo. This association is independent of age and vessel diameter.

Genetic variation in human stromelysin gene promoter and common carotid geometry in healthy male subjects

A common variant in the promoter of the human stromelysin gene, causing reduced enzyme expression, has been associated with the progression of coronary atherosclerosis. On the other hand, increased stromelysin activity may promote plaque rupture. The present study was undertaken to investigate the relationship between the genetic variation in the human stromelysin gene promoter and common carotid geometry. Forty-two healthy male subjects without major coronary heart disease risk factors were investigated. The polymorphism in the stromelysin gene promoter was studied through polymerase chain reaction amplification with the use of mutagenic primers. Age, blood pressure, lipids, glucose, viscosity, and body mass index were similar in homozygotes for the 5A allele (5A/5A), heterozygotes (5A/6A), and homozygotes for the 6A allele (6A/6A). Serum matrix metalloproteinase-3 levels did not differ significantly among genotypes. Common carotid diameters and intima-media thickness, measured by noninvasive ultrasonography, were significantly larger in 6A/6A subjects (for respective 6A/6A, 5A/6A, and 5A/5A subjects, diameter at the R wave was 0.63+/-0.09, 0.55+/-0.06, and 0.53+/-0.04 cm [mean+/-SD], P<0.005 by ANOVA; intima-media thickness was 765+/-116, 670+/-116, and 630+/-92 microm [mean+/-SD], P<0.05 by ANOVA). Wall shear stress, calculated as blood velocityxblood viscosity/internal diameter, was significantly lower in 6A/6A subjects (for respective 6A/6A, 5A/6A, and 5A/5A subjects, mean wall shear stress was 10.4+/-2.9, 13.5+/-3.5, and 12.6+/-1.9 dyne/cm(2) [mean+/-SD], P<0.05 by ANOVA). The results demonstrate that the gene polymorphism in the promoter region of stromelysin is associated with structural and functional characteristics of the common carotid artery in healthy male subjects without major risk factors for atherosclerosis. Individuals with the 6A/6A genotype (associated with lower enzyme activity) show a triad of events, namely, increased wall thickness, enlarged arterial lumen, and local reduction of wall shear stress, which might predispose them to atherosclerotic plaque localization.

Lack of association between carotid intima-media thickness and methylenetetrahydrofolate reductase gene polymorphism or serum homocysteine in non-insulin-dependent diabetes mellitus

We assessed the contribution of the serum homocysteine (Hcy) level, an independent risk factor for vascular disease, and methylene tetrahydrofolate reductase (MTHFR) gene polymorphism to the variability of intimal-medial thickness (IMT) of the common carotid artery in middle-aged non-insulin-dependent diabetes mellitus (NIDDM) subjects. One hundred thirty NIDDM patients (60 males and 70 females) with a mean age of 53 +/- 10 years and a mean diabetes duration of 11.3 +/- 7.9 years were enrolled for the study. Exclusion criteria included liver, heart, kidney, or other major-organ disease. Fasting total serum Hcy, folate, and vitamin B12 and clinical chemistry analyte levels were measured. MTHFR polymorphism was determined by polymerase chain reaction (PCR). IMT and plaques or stenosis in the common carotid were measured by ultrasonography. Serum Hcy was inversely correlated with vitamin levels and was slightly higher in subjects with the Val/Val genotype versus Ala/Val and Ala/Ala (P = .02); no differences in genotype were found in subjects with folate or vitamin B12 at or above the median level. In univariate analysis, common carotid IMT was significantly associated with age (P = .00001), the body mass index ([BMI] P = .0003), uric acid (P = .004), systolic blood pressure (P = .03), glycemia (P = .03), and total cholesterol (P = .04). No significant association was found between serum Hcy or MTHFR polymorphism and IMT. In multiple regression analysis, age (P = .0001), uric acid (P = .03), glycemia, and the BMI (P = .05) were independently associated with IMT and explained about 42% of IMT variability. In 130 NIDDM patients without nephropathy, basal levels of serum Hcy, as well as MTHFR polymorphism, did not predict significant changes in common carotid IMT.

[Statins: similarities and differences in the pharmacological, clinical and laboratory aspects]

The inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase (or statins) are the most powerful drugs affecting lipid and lipoprotein levels in plasma. Results obtained from large controlled trials using simvastatin, pravastatin and lovastatin for the primary or secondary prevention of coronary heart disease have demonstrated that treatment with statins is associated with a significant reduction in coronary morbidity and mortality and in total mortality. This is probably due to a more general anti-atherogenic effect of these drugs beyond their lipid-lowering activity. Meta-analysis of data from these large trials indicates that statins have an impact also on the incidence of cerebrovascular events. Currently, six statins have been approved for therapeutic use in different countries. In spite of the similarities in their chemical structure and mechanisms of action, statins may differ in many aspects such as pharmacological properties (hydrophilic vs lipophilic, elimination half-life, cytochrome P450 metabolism, etc.), effects on lipid and other biochemical variables, or pleiotropic effects on different metabolic processes related to atherosclerosis (endothelial function, platelet aggregation, immune function, etc.). In general, the safety and tolerability profile for all statins currently in use is good with a < 2% incidence of undesirable effects.

Influence of the human paraoxonase polymorphism (PON1 192) on the carotid-wall thickening in a healthy population

BACKGROUND

Serum paraoxonase (PON1) is a high-density lipoprotein-bound enzyme that can prevent oxidation of low-density lipoprotein and thus exert an anti-atherogenic effect. A polymorphism at codon 192 (Gln/Arg) of the PON1 gene gives rise to two isoforms that differ in substrate-dependent activity.

OBJECTIVE

To determine any independent contribution of this polymorphism to the variability of intimal-medial thickness (IMT) of the common carotid artery for a sample of asymptomatic adult subjects from southern Italy by ultrasonography.

METHODS

We studied 196 unrelated asymptomatic subjects (mean age 55.1 years), drawn from participants in a cardiovascular-disease-prevention campaign. Plasma levels of lipids and glucose were measured by routine methods. PON1 polymorphism was determined by polymerase chain reaction. IMT was measured from high-resolution B-mode echo-Doppler ultrasonography images.

RESULTS

Prevalences of alleles A (Gln) and B (Arg) were 0.68 and 0.32, respectively. We found no significant difference with regard to plasma levels of lipids and glucose and other variables among the PON1 genotypes, although subjects with BB had higher levels of triglycerides and lower levels of high-density lipoprotein cholesterol. Common carotid artery IMT was slightly greater in subjects with BB, although no significant association between PON1 genotypes and common carotid artery IMT was found, even after adjustment for confounding variables.

CONCLUSIONS

Our findings demonstrate that there is no significant association between PON1 gene polymorphism at codon 192 and common carotid artery IMT for an Italian population. However, the fact that we found slightly greater IMT in subjects with genotype BB would suggest that the study should be performed again with a larger sample.

Evaluation of common carotid hemodynamic forces. Relations with wall thickening

The localization of atherosclerotic lesions is influenced by hemodynamic factors, namely, shear stress and tensive forces. The present study investigated the relationships between shear stress and circumferential wall tension and between these hemodynamic factors and the intima-media thickness (IMT) of the common carotid artery in healthy men. Fifty-eight subjects were studied. Shear stress was calculated as blood viscosityxblood velocity/internal diameter. Circumferential wall tension was calculated as blood pressurexinternal radius. Blood velocity, internal diameter, and IMT were measured by high-resolution echo-Doppler. Mean shear stress was 12.6+/-3.3 dynes/cm(2) (mean+/-SD; range, 4.8 to 20.4) and was inversely related with age, blood pressure, and body mass index (BMI). Mean circumferential wall tension was 3.4+/-0.6x10(4) dynes/cm (range 2.4 to 5.6) and was directly associated with age and BMI. IMT was inversely associated with shear stress (r=0.55, P<0. 0001) and directly associated with circumferential wall tension (r=0. 43, P<0.0001). Shear stress and circumferential wall tension were inversely correlated (r=0.66, P<0.0001). In multiple regression analysis, shear stress and (marginally) cholesterol were independently associated with IMT, whereas circumferential wall tension, age, and BMI were not. These findings confirm that common carotid shear stress varies among healthy individuals and decreases as age, blood pressure, and BMI increase. Our findings also demonstrate that circumferential wall tension is directly associated with wall thickness, age, and BMI and that shear stress is associated with common carotid IMT independent of other hemodynamic, clinical, or biochemical factors.

NIDDM is associated with lower wall shear stress of the common carotid artery

The mechanisms underlying macrovascular complications in NIDDM are partially understood. In addition to increased prevalence and severity of systemic cardiovascular risk factors, local alterations of arterial wall and hemodynamics may play a role. Atherosclerotic lesions usually lie in regions of low wall shear stress. We therefore investigated the wall shear stress--that is, the frictional force acting tangentially to the endothelial surface--in the common carotid artery of diabetic and control subjects. Enrolled were 18 male NIDDM subjects and 18 age-matched control subjects. None of the participants were hypertensive, hyperlipidemic, or a cigarette smoker. Common carotid wall shear stress was calculated according to the following equation: blood viscosity x blood velocity/internal diameter. Blood viscosity was measured by use of a cone/plate viscometer. Blood velocity and internal diameter were measured by high-resolution echo-Doppler. Wall shear stress was significantly lower in NIDDM subjects than in control subjects (mean wall shear stress: 9.7 +/- 2.4 vs. 11.7 +/- 2.6 dynes/cm2, P < or = 0.005). Six diabetic participants had a plaque in one carotid tree and no lesions in the contralateral carotid. Among these subjects, mean wall shear stress was significantly lower in the side with lesion (8.1 +/- 1.6 vs. 10.5 +/- 2.4 dynes/cm2, P < or = 0.02). These findings suggest that diabetes is associated with a more atherosclerosis-prone carotid hemodynamic profile, which might represent an additional factor contributing to the increased prevalence and severity of carotid atherosclerosis in diabetic patients compared with general population.

Common mutation in methylenetetrahydrofolate reductase. Correlation with homocysteine and other risk factors for vascular disease

A common mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene results in elevated homocysteine levels and, presumably, in increased atherosclerotic risk. We evaluated serum homocysteine levels, MTHFR genotype, and a panel of variables in a sample of 155 middle-aged Italian subjects (mean age 38.1 years). Biometrical, hematological, and biochemical variables (including serum folate and vitamin B12) and lifestyle characteristics were investigated. MTHFR genotype was studied by polymerase chain reaction. The frequency of the genotype Val/Val (homozygosity for the mutant allele) was 16.13%. The Val/Val genotype was associated with increased levels of homocysteine; no differences among genotypes were seen in individuals with folate or vitamin B12 levels at or above the median values. In multivariate analysis, MTHFR genotype was an independent predictor of homocysteine levels in both biochemical and non biochemical regression models. Sex and diastolic blood pressure emerged as non biochemical variables independently associated with homocysteine. Apart from cofactors, uric acid was the only biochemical variable independently associated with homocysteine, particularly in subjects with Val/Val genotype. The observed parallel increases in homocysteine and uric acid levels in subjects with thermolabile MTHFR warrant further investigation.

Whole blood viscosity and haematocrit are associated with internal carotid atherosclerosis in men

BACKGROUND

Alterations in blood viscosity and haematocrit have been described in patients with coronary and cerebrovascular diseases. The results have not been conclusive, as modifications of these parameters are often associated with the presence of coronary heart disease (CHD) risk factors. The aim of this study was to verify whether blood viscosity and haematocrit are increased in patients with carotid atherosclerosis, independently of the presence of CHD risk factors.

METHODS

Male patients with internal carotid atherosclerosis (ICA+, n = 28) were selected from participants in a cardiovascular disease prevention campaign. Controls (ICA-, n = 28), also participating in the prevention campaign, were matched for age and all the classical CHD risk factors. Plasma lipids, glucose and fibrinogen were determined by routine methods. Cigarette smoking and current drug therapy was established by questionnaire. Whole blood viscosity was measured at shear rates of 450 and 225/s, using a cone-plate viscometer. Echo-Doppler of carotid arteries was performed with an ATL Ultramark 9 HDI using a 5-10 MHz multifrequency probe.

RESULTS

Blood pressure, plasma lipids, glucose, body mass index, fibrinogen and plasma viscosity were similar in the two groups. ICA+ patients, compared with the ICA- group, had significantly greater values of blood viscosity (4.52 +/- 0.37 cP compared with 4.18 +/- 0.45 cP, P < 0.005 respectively; shear rate 450/s) and haematocrit (48.57 +/- 3.19% compared with 45.57 +/- 4.81%, P < 0.008 respectively).

CONCLUSIONS

Our findings demonstrate that blood viscosity and haematocrit are increased in men with internal carotid atherosclerosis, independently of the presence of risk factors for atherosclerosis.

Carotid atherosclerosis in subjects with different hyperlipidaemia phenotypes

OBJECTIVE

To evaluate the presence of carotid plaque and/or stenosis in patients with different phenotype of hyperlipidaemia.

EXPERIMENTAL DESIGN

Case-control study.

SETTING

Outpatients metabolic clinic.

PATIENTS

Sixty type IIa, 50 type IIb and 40 type IV hyperlipidaemic subjects were compared with 50 normolipidaemic controls, matched for sex and age.

INTERVENTIONS

Blood lipid analysis for phenotype classification was performed after two months of diet. Blood pressure was measured by a zero-random sphygmomanometer. CHD risk factors, smoking habit, previous and ongoing drug therapy were assessed by a self-administered questionnaire. Echo-Doppler examination of the extracranial arteries (common, internal and external carotid artery and bulb) was done by a Multigon Angioview 600 provided with a 7.5 MHz probe for B-mode and 5 MHz for pulsed Doppler. Subjects were classified as having carotid atherosclerosis when a plaque and/or a stenosis was found in at least one of the examined segments and as normal when no atherosclerotic lesions were detected.

RESULTS

There were more hypertensives among type IV subjects whereas the prevalence of smokers and diabetics was similar in all four groups. The prevalence of carotid atherosclerosis was higher in type IIb and IIa subjects than in controls (58% and 38% respectively vs 14%, p<0.01) while in type IV subjects it was comparable to that of controls (25%).

CONCLUSIONS

The present findings show that hypercholesterolaemia and mixed hyperlipidaemia are frequently associated with carotid atherosclerosis, whereas hypertriglyceridaemia is not. The role of hypertriglyceridaemia in the development of atherosclerosis seems mediated by mechanisms other than plaque formation.

Awareness, treatment and control of hyperlipidaemia, hypertension and diabetes mellitus in a selected population of southern Italy

The purpose of the present study was to assess the degree of awareness, treatment and control of hyperlipidaemia compared with hypertension and diabetes mellitus in a selected population of southern Italy. All participants to a cardiovascular disease prevention campaign examined between April 1994 and July 1995 were screened for hyperlipidaemia, hypertension and diabetes mellitus. Subjects received also ECG, echo-Doppler of carotid arteries and filled in a questionnaire concerning personal and familial cardiovascular diseases, smoking habit and drug consumption. Of the 742 participants, 327 were found to have hypertension, 73 to have diabetes mellitus, 287 to have mild hyperlipidaemia and 322 to have moderate-severe hyperlipidaemia. Among hypertensive subjects, 60.2% were aware of their condition, 53.5% were treated and 15.6% had their blood pressure controlled at the recommended level (< 140/90 mmHg). Among diabetic subjects, 76.7% were aware, 64.4% treated and 19.2% reached fasting blood glucose level of less than 7.77 mmol/l (140 mg/dl). Only 24.0% of subjects with mild hyperlipidaemia were aware of their condition. Of the subjects found to have moderate-severe hyperlipidaemia, 64.9% were aware, 32.3% were treated and 9.0% had plasma cholesterol and triglycerides concentration of less than 6.45 and 5.65 mmol/l (250 and 500 mg/dl), respectively (cutoffs chosen to separate mild from moderate-severe hyperlipidaemia). These results show that mild hyperlipidaemia is almost neglected whereas awareness of moderave-severe hyperlipidaemia is quite widespread and comparable to that of hypertension and diabetes mellitus. Prevalence of treatment and control of moderate-severe hyperlipidaemia is, however, much lower than that of hypertension and diabetes.

In vivo association between low wall shear stress and plaque in subjects with asymmetrical carotid atherosclerosis

BACKGROUND AND PURPOSE

It is known that atherosclerosis does not involve both carotid arteries to the same extent. Pathological investigations have demonstrated that lesions develop in regions of low wall shear stress. The aims of the present study were to verify the degree of carotid atherosclerosis asymmetry in a population-based study and to evaluate whether wall shear stress is lower in carotids with atherosclerotic lesions than in carotids without lesions.

METHODS

Participants in a cardiovascular disease prevention campaign (n = 1166) were screened for carotid atherosclerosis by echo-Doppler examination. Of these, 23 subjects who presented plaque in the common carotid or bulb of one side and no plaque in the contralateral carotid tree were enrolled for common carotid wall shear stress measurement. Shear stress was calculated according to the following formula: Shear Stress = Blood Viscosity x Blood Velocity/Internal Diameter.

RESULTS

Of the 1166 subjects screened, 400 (34%) had plaque and/or stenosis in the carotids. Ninety subjects had lesions exclusively in the right carotid, 111 had lesions exclusively in the left, 70 had lesions in both carotids but with different degrees of severity, and only 129 had similar lesions in both carotids. In the 23 subjects in whom wall shear stress was measured, peak shear stress was 18.7 +/- 4.1 and 15.3 +/- 4.0 dynes.cm-2 (mean +/- SD) (P < .0001) in the side without and the side with plaque, respectively. Mean shear stress yielded similar results.

CONCLUSIONS

The present results demonstrate that the atherosclerotic involvement of carotid arteries is usually asymmetrical and that wall shear stress is lower in the carotid arteries where plaques are present than in plaque-free arteries. These findings provide in vivo evidence for a strong association between shear stress and atherosclerotic lesions.

[Non-Hodgkin's lymphoma of the spleen and hepatitis C. Report of a clinical case]

We report a clinical case of a patient affected by splenic non-Hodgkin lymphoma and virus C hepatitis. It seems that this kind of association is original because as far as we know the association between non-Hodgkin lymphoma and HCV did not include non-Hodgkin lymphoma involving the spleen. Indeed, in our patient, there was an increase of CD/57 lymphocytes. In our opinion this could be interesting in the disorders of the immune system associated with lymphoma.

Correction of erythrocyte shape abnormalities in familial hypercholesterolemia after LDL-apheresis: does it influence cerebral hemodynamics?

It is well known that red blood cells incubated in low-density lipoprotein (LDL)-rich medium show shape abnormalities that revert to normal after reincubation in normal plasma. Patients with homozygous familial hypercholesterolemia (HFH) have an increased percentage of abnormally-shaped erythrocytes (mostly stomatocytes, knisocytes, and crenated cells) compared to normocholesterolemic controls: 7.73+/-0.96 versus 3.52+/-0.52 (mean+/-SEM; P = 0.001). To confirm the role of high LDL concentration in inducing red cell shape abnormalities we determined the percentage of abnormally shaped erythrocytes in seven HFH patients 1 day after the procedure of LDL-apheresis with a 40% cholesterol decrease. A reduction in kniscocytes, stomatocytes, and crenated cells was observed in the patients treated by LDL-apheresis (P < 0.01). To investigate the possible benefit of a reduction in erythrocyte shape abnormality on cerebral hemodynamics, cerebral flow velocity, as evaluated by transcranial Doppler, was evaluated concomitantly and found to be remarkably increased after apheresis (P < 0.01). No significant change in hematocrit, plasma viscosity, blood viscosity, mean pressure, or cardiac output was detected, 1 day after apheresis. An inverse correlation was demonstrated (r = 0.55; P = 0.04) between changes in the percentage of knisocytes+stomatocytes +crenated cells and percent changes in middle cerebral artery peak systolic velocity. The correction of erythrocyte shape abnormalities after LDL-apheresis might be related to dramatic changes in plasma phospholipid concentration and proportion occurring after this procedure in HFH patients. The reduction of erythrocyte shape abnormalities could contribute, together with other hemorheological factors, to the improvement of cerebral hemodynamics after LDL-apheresis.

Association between intima-media thickness and wall shear stress in common carotid arteries in healthy male subjects

BACKGROUND

Atherosclerotic lesions lie in regions of low wall shear stress. No relationship between wall shear stress and intima-media thickness in vivo has been reported. Aims of the present study were to verify the reproducibility of wall shear stress measurement in vivo and to evaluate its association with intima-media thickness in the common carotid artery in healthy subjects.

METHODS AND RESULTS

Wall shear stress was calculated according to the following formula: Shear Stress = Blood Viscosity x Blood Velocity/Internal Diameter. Blood viscosity was measured by use of a cone/plate viscometer. Blood velocity, internal diameter, and intima-media thickness were measured by high-resolution echo Doppler. Twenty-one healthy male subjects were investigated. Peak and mean shear stress values were 29.5 +/- 8.2 and 12.1 +/- 3.1 dynes/cm-2 (mean +/- SD), respectively. Peak shear stress was inversely related to intima-media thickness (r = .62), age (r = .77), systolic blood pressure (r = .61), and body mass index (r = .59) (P < .001 for all coefficients). Mean shear stress yielded similar results. The relationship between shear stress and intima-media thickness was independent of age, blood pressure, and body mass index. The reproducibility, calculated by Kendall's W test, was statistically significant.

CONCLUSIONS

Our results demonstrate that common carotid artery wall shear stress measurement in vivo is reproducible. It inversely relates to intima-media thickness, age, systolic blood pressure, and body mass index. These findings confirm in vivo the role of shear stress in intima-media thickening.

[Rendu-Osler-Weber disease. Report of a clinical case]

Rendu-Osler-Weber disease is an hereditary disorder characterized by cutaneo-mucous telangiectasis and vascular abnormalities in several organs. Bleeding, especially epistaxis, represents the most important clinical feature. Pulmonary arteriovenous fistulae can cause hypoxaemia, haemoptysis, polycythaemia and clubbing. Diagnosis is based on family and personal history, teleangiectasis, laboratory (haemochrome, fibrinogen, PT, PTT) and instrumental findings (endoscopy and/or roentgen). Therapy depends on symptoms. Embolization of pulmonary arteriovenous fistulae and laser treatment of intestinal vascular abnormalities have been successful. Danazol treatment yielded controversial results. We report the case of a patient admitted for arterial hypertension and recurrent epistaxis. Rendu-Osler-Weber disease diagnosis was made based on positivity at family and personal history, clinical examination, laboratory and instrumental findings. In conclusion we underline the pivotal role of anamnesis and clinical examination in the differential diagnosis of hereditary bleeding disorders and emphasize the importance of early diagnosis for the correct therapeutic approach.