A novel model concept for modelling the leaching of natural toxins: results for the case of ptaquiloside.

Phytotoxins are a large class of highly diverse emerging environmental contaminants that have been detected at high concentrations in plants, water and soils. This study presents a novel modelling approach for assessing the fate of plant toxins in the soil-plant-atmosphere continuum, developed for the specific case of ptaquiloside (PTA), a carcinogenic phytotoxin produced by Pteridium aquilinum. The mechanistic model DAISY has been adapted for reproducing phytotoxin dynamics in plants, covering processes such as toxin generation in the canopy, wash off by precipitation and toxin recovery in the canopy after depletion events. Transport of the toxin in the soil was simulated by the advection-dispersion equation assuming weak sorption and degradation for two Danish soils. The model simulates realistic toxin contents in the plant during the growing season, where the actual PTA content is dynamic and a function of the biomass. An average of 48% of the PTA produced in the canopy is washed off by precipitation, with loads in the soil often in the order of mg m-2 and up to a maximum of 13 mg m-2 in a single rain event. Degradation in the soil removes 99.9% of the total PTA input to the soil, while only 0.1% leaches into the soil. The median annual flux-averaged predicted environmental concentrations during single events are often in the order of µg L-1, reaching up to 60 µg L-1 for the worst-case scenario. The simulated results for both degradation and wash off are of the same order of magnitude as the published data. Based on the results, we conclude that DAISY, with the newly implemented processes, is a useful tool for understanding, describing and predicting the fate of PTA in the soil. Further work comparing the model results with real data is needed for the calibration and validation of the model.

Strong sesquiterpene emissions from Amazonian soils.

The Amazon rainforest is the world's largest source of reactive volatile isoprenoids to the atmosphere. It is generally assumed that these emissions are products of photosynthetically driven secondary metabolism and released from the rainforest canopy from where they influence the oxidative capacity of the atmosphere. However, recent measurements indicate that further sources of volatiles are present. Here we show that soil microorganisms are a strong, unaccounted source of highly reactive and previously unreported sesquiterpenes (C15H24; SQT). The emission rate and chemical speciation of soil SQTs were determined as a function of soil moisture, oxygen, and rRNA transcript abundance in the laboratory. Based on these results, a model was developed to predict soil-atmosphere SQT fluxes. It was found SQT emissions from a Terra Firme soil in the dry season were in comparable magnitude to current global model canopy emissions, establishing an important ecological connection between soil microbes and atmospherically relevant SQTs.

Post-exercise ankle-brachial index is not an indispensable tool for the detection of peripheral arterial disease in an epidemiological survey. A post-hoc analysis of the Athens Study.

AIM: Previous studies have estimated the sensitivity, specificity and predictive value of non-invasive methods for the detection of peripheral arterial disease (PAD). The aim of our study was to evaluate the performance of non-invasive diagnostic tools and more specifically ankle-brachial index (ABI) at rest and after exercise for the detection of PAD in an epidemiological survey conducted in Greece. METHODS: Overall, a representative sample of 2089 adults (911 men and 1178 women), 18-90 years old (mean age 46.88+14.98 years) living in the greater Athens area, participated in the study. For the detection of intermittent claudication, the Rose questionnaire (RQ) was used. Moreover, physical examination (PE) of the lower extremities was performed, ABI both at rest and after exercise was measured. RESULTS: Thirty subjects were diagnosed with PAD, corresponding to a prevalence of 1.43%. Sensitivity and specificity of RQ, PE, ABI at rest and one minute after stress test were 53.33%, 66.67%, 100%, 64.71% and 98.79%, 97.77%, 99.81%, 94.94%, respectively. The combination of RQ with PE and ABI at rest yielded a 41.18% sensitivity, but a very high specificity (100%) and positive predictive value (100%). CONCLUSION: ABI at rest detected PAD in the epidemiological setting, and its combination with RQ and PE attained a very high specificity. Intermittent claudication and physical examination, while easier to evaluate, were considerably less sensitive. Finally, inclusion of postexercise ABI did not increase sensitivity which leads to the conclusion that this diagnostic tool is not needed for the detection of PAD in large epidemiological surveys.

Phytosterols supplementation decreases plasma small and dense LDL levels in metabolic syndrome patients on a westernized type diet.

BACKGROUND AND AIMS: Several studies have observed a hypocholesterolemic effect of plant sterols in hypercholesterolemic patients on a balanced diet. The aim of this study was to examine the effect of phytosterol supplementation on risk factors of coronary artery disease in metabolic syndrome patients on a Westernized type diet. METHODS AND RESULTS: In a randomized placebo-controlled design 108 patients with metabolic syndrome were assigned to consume either 2 plant sterol-enriched yogurt mini drink which provided 4 g phytosterols per day, or a yogurt beverage without phytosterols (control). The duration of the study was 2 months and the patients in both groups followed their habitual westernized type diet and recording it on food diaries. Blood samples were drawn at baseline and after 2 months of intervention. After 2 months supplementation with phytosterols, a significant reduction in total cholesterol, LDL-cholesterol, small and dense LDL (sdLDL) levels, as well as, apoB and triglycerides concentrations were observed in the intervention group (P < 0.05) compared to the control group. In addition, phytosterol supplementation lowered serum total cholesterol by 15.9%, LDL-cholesterol by 20.3% and triglyceride levels by 19.1% (P = 0.02, P < 0.001 and P < 0.001, respectively), although the patients kept their habitual westernized type diet. No differences were observed in HDL cholesterol, apoA1, glucose, C-reactive protein, fibrinogen levels and blood pressure. CONCLUSIONS: Phytosterol supplementation improves risk factors of coronary artery disease even if the diet is a westernized type.

Differential impact of angiotensin receptor blockers and calcium channel blockers on arterial stiffness.

AIM: Arterial stiffness, assessed by ambulatory arterial stiffness index (AASI), is an independent predictor of cardiovascular disease (CVD) mortality in hypertensives. However, it is unclear whether certain antihypertensive drugs are conducive to the reduction in CVD morbidity and mortality through their beneficial effect on arterial stiffness. Therefore, we compared the effect of angiotensin receptor blockers (ARBs) and calcium channel blockers (CCBs) on AASI in a hypertensive population. METHODS: We studied 188 individuals with newly-diagnosed essential hypertension without organ damage or CVD. AASI was calculated from twenty-four-hour ambulatory blood pressure monitoring (ABPM) readings at baseline and after twelve weeks of antihypertensive treatment. Therapy was initiated with a low-dose of CCB (group A) or ARB (group B). After six weeks, subjects with poor office blood pressure (BP) control were further randomized to high-dose monotherapy (CCB in group C or ARB in group D) or low-dose combination therapy (CCB plus ARB, group E). RESULTS: Groups A and B showed similar reductions in systolic and diastolic BP (r=-0.12, P=0.92 and r=-0.07, P=0.58 in group A and r=-0.06, P=0.67 and r=-0.04, P=0.73 in group B, respectively). However, only subjects in group B achieved significant AASI decrease (P<0.001). Similarly, subjects in groups C, D and E also displayed a comparable BP reduction, but only those in group E attained significant AASI decrease (P=0.001). CONCLUSION: ARB treatment, either as low-dose monotherapy or in combination with a CCB in hypertensives who do not achieve BP control with monotherapy, has a beneficial effect on arterial stiffness. As arterial stiffness is an important modifiable risk factor, our findings highlight the value of ARBs beyond their BP lowering properties.

Dynamic sorption of ammonium by sandy soil in fixed bed columns: Evaluation of equilibrium and non-equilibrium transport processes.

The release of excess nitrogen-containing compounds into groundwater is a major concern in aquifer recharge by the Soil Aquifer Treatment (SAT) process. Ammonium (NH(4)(+)) is one of the most nocive and common nitrogen compounds in wastewaters. In order to assess the risk of wastewater use for aquifer recharge, NH(4)(+)adsorption onto Souhil wadi soil sampled from the SAT pilot plant (Nabeul, Tunisia) was studied using laboratory columns experiments. Several experiments were conducted using aqueous synthetic solutions under different aqueous ammonium concentrations and flow rates. Furthermore, a real wastewater solution was used to test the effect of competitive cations contents on NH(4)(+) adsorption. Afterwards, the Hydrus-1D model was used in inverse mode to simulate the ammonium transport through the Souhil wadi soil. For the synthetic solutions, the adsorbed ammonium amount varied from 1 to 30.7 mg kg(-1) for aqueous ammonium concentrations between 4.9 and 36.4 mg L(-1). The linear isotherm model was found to be the most suitable for describing this adsorption. The flow rate decrease from 45 to 15 mL min(-1) induced an increase in the ammonium adsorption capacity by 49%. Indeed, the lesser the flow rate is, the longer the residence time and the higher the exchange between the aqueous solution and soil matrix. The use of wastewater instead of aqueous synthetic solution decreased about 7 times the Souhil wadi adsorption capacity of ammonium because of its relatively high concentrations of competitive ions such as calcium and magnesium. The use of the Hydrus-1D model showed that the chemical non-equilibrium model was the best to simulate the ammonium transport through the laboratory soil columns.

The effect of metformin on the incidence of type 2 diabetes mellitus and cardiovascular disease risk factors in overweight and obese subjects--the Carmos study.

UNLABELLED: We investigated whether the addition of metformin to the treatment of overweight and obese individuals further reduces the incidence of type 2 diabetes mellitus (T (2)DM), prediabetes and metabolic syndrome (MetS) and improves cardiovascular disease (CVD) risk factors (RFs). DESIGN AND METHODS: We studied 366 adults (mean age 53.0+/-0.5 SE years, and mean BMI 32.3+/-0.2 SE Kg/m (2)) without CVD. All subjects received lifestyle recommendations and drug management of CVD-RFs, whilst 95 of them were additionally given metformin. The follow-up period lasted 12 months. RESULTS: At the end of the study the frequency of T (2)DM in the metformin and non-metformin group was 1.1 and 8.1%, respectively (risk difference=-7% with 95% CI from -12.7% to -1.4%, p=0.012). Participants with prediabetes displayed a greater reduction in the incidence of T (2)DM after taking metformin compared to those who had not received this drug (risk difference=-18.5% with 95%CI from -33.1% to -3.9%, p=0.010). Metformin had a similar beneficial impact on subjects with MetS (risk difference=-12.9% with 95% from -25% to -0.7%, p=0.040) and this was attributed to the greater increase in HDL-C (p=0.046) and decrease in fasting plasma glucose levels (p=0.024). Metformin also achieved a greater reduction in total cholesterol and LDL-C levels (metformin vs. non-metformin treated subjects: -31.9 vs. -17.3 mg/dl, p=0.001, and -26.2 vs. -15.9 mg/dl, p=0.006, respectively). CONCLUSIONS: Metformin reduces the occurrence of T (2)DM in overweight and obese non-diabetic adults and decreases the rate of MetS by improving the CVD risk factor profile.

Metabolic syndrome and prediabetes identify overlapping but not identical populations.

OBJECTIVE: The metabolic syndrome (MetS) is a cluster of risk factors related to cardiovascular disease. Prediabetes, identified by impaired fasting glucose and/or impaired glucose tolerance, may predict future development of diabetes mellitus. However, it is not clear whether MetS and prediabetes represent the same or different clinical entities. This study compares MetS and prediabetes in terms of cardiovascular risk factors and target organ damage. RESEARCH DESIGN AND METHODS: A total of 524 overweight and obese (body mass index, BMI >or= 27 kg/m (2)) adults, mean age 53.6 +/- 10.3 years, 264 men and 260 women, were studied. All participants underwent a thorough clinical and laboratory evaluation, including an oral glucose tolerance test and insulin measurements. Echocardiography, carotid ultrasonography, and pulse wave analysis were also performed for the detection of target organ damage. NCEP-ATP III and ADA criteria were used for the diagnosis of MetS and prediabetes. RESULTS: The prevalence of MetS and prediabetes was 38.7 and 25.4 %, respectively. Overall, 129 individuals (24.6 %) had MetS without prediabetes (group M) and another 59 (11.3 %) prediabetes without MetS (group P). Group P had decreased albumin excretion (p = 0.033) and more thickened common carotid intima-media in comparison to group M (p = 0.032). Furthermore, group M was associated with higher C-reactive protein levels. Multiple logistic regression analysis revealed that advanced age (p < 0.0001, OR 1.11, 95 % CI 1.06 - 1.16), low insulin secretion (p < 0.0001, OR 0.05, 95 % CI 0.02 - 0.18 for insulinogenic index), and increased insulin resistance (p = 0.0003, OR 3.22, 95 % CI 1.71 - 6.07 for HOMA-IR) were associated with group P. CONCLUSIONS: Our data demonstrate that MetS and prediabetes have an overlapping pattern. MetS appears to have a more pronounced effect on early renal dysfunction and increased inflammatory activation, while prediabetes tends to be associated with early carotid structural changes. These findings may be due to a different pathophysiologic substrate of these clinical phenotypes in terms of insulin resistance and secretion, as well as to the varying prevalence of cardiovascular risk factors.

Early vascular lesions in subjects with metabolic syndrome and prediabetes.

AIM: The metabolic syndrome (MetS) is a cluster of cardiovascular risk factors, while prediabetes, identified by impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT), predicts future development of diabetes mellitus. Although MetS and prediabetes have a strong interrelation, it is unclear whether they denote the same risk for cardiovascular complications. The aim of the study was to compare overweight and obese individuals with MetS and prediabetes in terms of early carotid artery atheromatosis and renal dysfunction. METHODS: A total of 524 overweight and obese (body mass index, BMI = or >27 kg/m2) adults, mean age 56.7+/-11.8 years, 264 men and 260 women, were studied. All participants underwent a thorough clinical and laboratory evaluation, including an oral glucose tolerance test. Carotid artery ultrasonography was performed and 24 h urine albumin excretion was measured. NCEP-ATP III and ADA criteria were used for the diagnosis of MetS and prediabetes. RESULTS: Overall, 129 individuals (24.6%) had MetS without prediabetes and another 59 (11.3%) prediabetes without MetS. Individuals with prediabetes had lower albumin excretion (P=0.033) and more thickened common carotid intima-media in comparison to those with MetS (P=0.032). Furthermore, MetS was associated with higher C-reactive protein levels in comparison to prediabetes (P=0.05). CONCLUSIONS: The MetS seems to have a more pronounced impact on early renal dysfunction than prediabetes, while the latter to early carotid artery structural changes.

The control of dyslipidemia in outpatient clinics in Greece (OLYMPIC) Study.

The objective of this study was to determine the proportion of Greek patients referred to outpatient clinics for dyslipidemia who achieved the low-density lipoprotein cholesterol (LDL-C) goal defined by the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) guidelines, using lifestyle changes, lipid-lowering drug treatment (LLDT), or both. Adult patients with dyslipidemia, who had been receiving a hypolipidemic diet and/or LLDT for at least 3 months were assessed in a multicenter study performed at 66 sites across Greece. Patients were followed up for an additional 3-month treatment period. Lipid levels were recorded at baseline and at the end of the study. The primary endpoint was the proportion of patients achieving their individual LDL-C target at the end of the study, according to their coronary heart disease (CHD) risk status or its equivalents, as defined by the NCEP-ATP III guidelines. Multivariate logistic models were used to identify determinants of undertreatment. The study included 2,660 adults (20-75 years) from 7 regions of Greece. Of the evaluable sample (n = 2,211; men 51%; mean age 62 +/-9 years) 81% were receiving LLDT (96% with statins and 3% with fibrates), 44% had a history of CHD, 61% arterial hypertension, 36% diabetes, and 26% a family history of premature CHD. Overall, 6% were at low CHD risk, 30% at medium CHD risk, and 63% at high CHD risk. At the end of the study, 26% of all patients and 30% of those receiving LLDT achieved the NCEP-specified LDL-C target levels. The percentage of patients at LDL-C goal according to CHD risk status was: low risk 67% (95% CI = 59-75), medium risk 29% (95% CI = 26-33), and high risk 20% (95% CI = 18-22). Statins proved to be more effective than fibrates (p <0.0001). Atorvastatin-treated subjects (n = 1,222, mean dose 19 mg/day) attained the LDL-C target (31% of the cases) at a higher rate than those receiving other LLDT (n = 574, 26% at target, p <0.01) or not receiving drug treatment (n = 415, 8%, p <0.001). This outcome was more evident in the high-CHD risk group (n = 1,402, 26% with atorvastatin vs 16% with other LLDT and 3% not receiving LLDT attained the LDL-C goal, ANOVA, p <0.001). The majority of dyslipidemic patients receiving LLDT, mainly those with high-CHD risk, are not achieving the NCEP LDL-C target. This is mainly explained by inadequate dose titration to ensure target goals are met. Promoting healthy lifestyle and appropriate LLDT (potent statins with sufficient dose titration) must be implemented to ensure that patients attain LDL-C treatment goals and thus benefit from the reduction in individual CHD risk.

High-dose monotherapy vs low-dose combination therapy of calcium channel blockers and angiotensin receptor blockers in mild to moderate hypertension.

The objectives of the study were to compare long-acting dihydropyridine calcium channel blockers (CCBs) with angiotensin II receptor blockers (ARBs) according to the ambulatory blood pressure monitoring (ABPM) profile in stage 1 and 2 newly diagnosed hypertensives and also to evaluate the efficacy of high-dose monotherapy vs low-dose combination therapy of the two drug categories among the subjects with inadequate blood pressure (BP) control after conventional low-dose monotherapy. We obtained 24-h ABPM readings from 302 subjects with newly diagnosed stage 1 or 2 essential hypertension. The study protocol consisted of initial drug treatment with a low dose of either CCBs or ARBs. Hypertensives who did not achieve BP control were randomized to high-dose monotherapy of either category of drug or low-dose combination therapy. CCBs and ARBs in low-dose monotherapy achieved BP control in 53.8 and 55.3% of the cases, respectively. However, subjects under treatment with CCBs experienced side effects more often and required that treatment be discontinued. Hypertensives who failed to control their BP with low-dose monotherapy did significantly better with low-dose combination treatment (61.6%) than with high-dose CCBs (42.8%) or ARBs (40.5%) monotherapy (P<0.05). In terms of ABPM, low-dose combination therapy exhibited better 24-h BP profile according to trough-to-peak ratio, hypertensive burden and BP variability. In conclusion, low-dose ARBs and CCBs have a comparable effect in subjects with grade 1 and 2 arterial hypertension. In hypertensives who are not controlled by low-dose monotherapy, low-dose combination therapy proves be more efficacious than high-dose monotherapy.

Impaired erythrocyte deformability precedes vascular changes in experimental diabetes mellitus.

The effect of diabetes on the red blood cell (RBC) deformability and its association with histological vascular changes was investigated in 35 streptozotocin-induced diabetic Wistar rats in a 30-day experiment and compared to 10 controls. RBC deformability was significantly impaired in the diabetic rats on day 5 (p < 0.001) and continued to deteriorate until day 20. On the 20 (th) day, the diabetic rats were randomly divided into two groups (group A: insulin-treated; group B: non-insulin-treated). A slight, non-significant (p = 0.20) improvement in RBC deformability was noticed in the insulin-treated group. In vitro incubation of RBCs with insulin did not improve the acquired RBC rigidity in either diabetic group. In contrast, it caused a significant reduction in RBC-deformability in the controls. On day 30, histological examination of arterial specimens from various sites revealed moderate to significant thickening in medium- and small-size artery and arteriole walls in both diabetic groups, with no evidence of diabetes-related changes in large, elastic-type arteries. No vascular changes were noticed in nine diabetic rats that succumbed between days 10 and 15. The results of this study indicate that reduced RBC deformability is an early manifestation of abnormal blood rheology in experimental diabetes, and precedes the evolution of vascular changes.

HLA phenotypes as promoters of cardiovascular remodelling in subjects with arterial hypertension.

The objective of this study was to investigate the association between human leukocyte antigens (HLA) phenotypes and cardiovascular remodelling, as expressed by left ventricular mass (LVM) and carotid intima-media thickness (IMT), in hypertensives. We examined 153 subjects with arterial hypertension and 61 normotensive controls living in the greater Athens area. The population was classified into three groups and specifically group I (normotensives), group II with Grade 1 hypertension and group III with Grade 2 or 3 hypertension. HLA class I and class II antigens were studied by microlymphocytotoxic technique. Carotid IMT and LVM were determined by ultrasonography. The prevalence of HLA DQ7 in the hypertensive cohort was 27.4% that was significantly smaller than the 52.5% among the controls (P = 0.002). The HLA DR11 was found in 24.0% of the hypertensives and in 52.5% of the controls (P < 0.001). Group III hypertensives with HLA DR11 exhibited significantly higher LVM/h in comparison to the hypertensives without this HLA (199.0 +/- 28.8 vs 171.2+44.1g/m, P = 0.009). This association was not present in groups I and II. Similarly, group III hypertensives with HLA DQ7 were characterized by higher IMT in comparison to those without this HLA (0.94 +/- 0.19 vs 0.83 +/- 0.23 mm, P = 0.048). HLA DR17 was associated with higher IMT in both groups II and III (1.00 +/- 0.19 vs 0.82 +/- 0.19 mm, P = 0.046 and 1.01 +/- 0.23 vs 0.84 +/- 0.22 mm, P = 0.049, respectively) but not in group I. In conclusion, certain HLA phenotypes may be related to the levels of arterial blood pressure. Moreover, it seems that these HLA phenotypes may identify subjects with arterial hypertension that are more prone to develop cardiovascular hypertrophy.

Intermittent claudication unmasking underlying Fabry's disease.

In a 53-year-old woman, admitted to our Department with leg pain, peripheral arterial occlusive disease (PAOD) was diagnosed. The absence of cardiovascular risk factors in this middle-aged woman, the unexplained burning pain during both effort and rest of the lower extremities mimicking severe ischemia, decreased sweating and cold induced Raynaud's phenomenon raised the suspicion of an underlying predisposing disease. The coexistence of painful acroparesthesias, angiokeratomas, left ventricular hypertrophy (LVH), corneal opacities and lenticular lesions suggested the diagnosis of Fabry's disease, which was confirmed by low serum levels of a-galactosidase-A activity. This case, presented with intermittent claudication due to generalized atherosclerosis, is quite unusual, since Fabry's disease rarely produces symptoms in female carriers.

Atherosclerosis of carotid arteries and the ace insertion/deletion polymorphism in subjects with diabetes mellitus type 2.

BACKGROUND: The aim of the present study was to investigate the association of the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism with the ultrasonographically evaluated severity and characteristics of carotid artery atherosclerosis in subjects with diabetes mellitus type 2. METHODS: We assessed 184 subjects with diabetes mellitus type 2, 75 males and 109 females, mean age 61.4+/-7.7 years. All subjects were receiving oral antidiabetic drugs for glycemic control and were free of cardiovascular events. The ACE genotype was analyzed by the polymerase chain reaction (PCR) technique. The ultrasonographic examination of the carotid arteries was performed in both B-mode imaging and Doppler ultrasound. The common carotid artery intima-media thickness was assessed 15-20 mm proximal to the dilatation of the carotid bulb. The atheromatous lesions were classified according to their echogenic characteristics as predominantly echolucent, mixed and predominantly echogenic with under 30, 30-70 and over 70% of the total plaque area echogenicity, respectively. RESULTS: From the total cohort 29 (15.8%) subjects had the II, 86 (46.7%) the ID and 69 (37.5%) the DD ACE genotypes. The mean carotid artery diameter stenosis was 37+/-17%, 43+/-19% and 40+/-20% (p=NS) and the intima media thickness was 0.94+/-0.24 mm, 0.97+/-0.20 mm and 0.98+/-0.20 mm (p=NS) in the II, ID and DD subgroups, respectively. When the echogenicity was analyzed according to the ACE I/D polymorphism, 12 subjects (41.4%), 13 (44.8%) and 4 (13.8%) with II genotype had predominantly echogenic, mixed and predominantly echolucent lesions, respectively. The ID genotype diabetics were found to have predominantly echogenic plaques in 41 cases (47.7%), mixed in 30 (34.9%) and predominantly echolucent in 15 cases (17.4%). From the 69 DD subjects 19 (27.5%) had predominantly echogenic plaques, 26 (37.7%) had mixed and 24 (34.8%) had predominantly echolucent lesions. Predominantly echolucent plaques were more frequently encountered among diabetics with the DD genotype (p<0.05), even after correction for demographic characteristics, the main risk factors of atherosclerosis and blood glucose control. CONCLUSIONS: The ACE genotype seems to be associated with the echogenicity of carotid artery atheromatosis but not with the common carotid artery intima media thickness or the degree of internal carotid artery stenosis in subjects with type 2 diabetes mellitus. The DD genotype may be implicated in the increased cardiovascular risk that characterizes echolucent plaques.

Association of the HLA antigens with early atheromatosis in subjects with type 2 diabetes mellitus.

BACKGROUND: Inflammation plays an important role in the pathogenesis of atherosclerosis. The major histocompatibility complex, as expressed by the human leukocyte antigens (HLA) is considered to regulate the immune response. The aim of this study was to investigate the association of the HLA antigens with vascular remodeling estimated by the carotid intima-media thickness (IMT) in subjects with type 2 diabetes mellitus (DM). METHODS: We evaluated 197 patients with type 2 DM, 80 males and 117 females, mean age 61.8+/-7.8 years, with no history of cardiovascular events. The presence of other major cardiovascular risk factors was recorded. The currently identified HLA class I (-A, -B, -Cw) and class II (DR, -DQ) antigens were studied by a classical 2 step microlymphocytotoxic technique in peripheral blood T and B lymphocytes. Measurements of the IMT were performed in the right and left common carotid arteries, 15-20 mm proximal to the dilatation of the carotid bulb in an end-diastolic "frozen" and magnified B-mode ultrasonographic image. Glycosylated hemoglobin A1c (HbA1c) and C-reactive protein (CRP) were also measured. The results are presented as mean +/-1 standard deviation. RESULTS: Regarding the HLA phenotypes in the final analysis we tested a total of 24 HLA antigens that exhibited a frequency of at least 5% in our diabetic population. Only HLA A3 was found to be significantly associated with the carotid IMT. Forty-nine (24.9%) diabetics were HLA A3 positive (group A), while 148 (75.1%) were HLA A3 negative (group B) and had mean IMT of 0.89+/-0.16 mm and 0.98+/-0.21 mm, respectively (p<0.01). Also the two groups differed significantly in respect to CRP, with group A exhibiting lower serum levels (1.1+/-0.4 mg/dl vs 2.6+/-0.7 mg/dl for group A and B, respectively, p<0.05). However, no differences were observed between the two groups as far as blood glucose control, arterial hypertension and dyslipidaemia were concerned. CONCLUSIONS: Human leukocyte antigen A3 is associated with less vascular damage, as expressed by carotid wall thickness, in subjects with type 2 DM. These subjects may be characterized by a milder inflammatory response, as shown by the lower serum levels of CRP.