Asymmetric dimethylarginine as a risk factor for cardiovascular disease in Japanese patients with type 2 diabetes mellitus

Alcohol Drinks Induce Acute Lowering in Circulating l-Arginine in Obese and Type 2 Diabetic Subjects

Since low serum l-arginine (Arg) and high asymmetric dimethylarginine (ADMA) can predict microvascular complications in type 2 diabetes mellitus (T2DM), we tested whether Arg and ADMA are affected by diet and physical activity in overweight/obese and T2DM subjects. We tested the effects on serum Arg and ADMA of single loads of dextrose, protein, fat, or alcohol (∼300 calories each); one episode of physical exercise; and 12 weeks of standard lifestyle modification (dietary and physical activity counseling). Alcohol drink was followed by ∼30% lowering in Arg. Arg and ADMA increased after a protein load but remained stable after glucose or fat load or 30 min of treadmill walk. Following 12 weeks of lifestyle modification, ADMA declined only in subjects achieving weight loss >5%. In conclusion, alcohol is a previously unrecognized acute suppressor of serum Arg. Lifestyle modification lowers ADMA in subjects who achieve weight loss >5%. Clinical Trial Registration Number: NCT04406402.

DDAH1 promoter -396 4N insertion variant is associated with increased risk of type 2 diabetes in a gender-dependent manner

Background

Asymmetrical dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthases, making it a contributing factor for diabetes. Endogenous ADMA is hydrolyzed by dimethylarginine dimethylaminohydrolase 1 (DDAH1), and a DDAH1 promoter ‐396 4N deletion/insertion polymorphism (DDAH1: ‐396_‐395insGCGT) regulates its transcriptional activity. This study aimed to explore the association between this polymorphism and type 2 diabetes (T2DM).

Methods

In a case–control study, all participants were genotyped for this polymorphism within two sets of populations (discovery: 1,227 T2DM patients and 1,339 controls; replication: 1,190 patients and 1,651 controls). The disease association was assessed by a unconditional logistic regression model. Homeostasis model assessment calculations were conducted among different genotypes.

Results

We identified that DDAH1: ‐396_‐395insGCGT insertion allele was significantly associated with increased risk of T2DM (discovery: adjusted odds ratio [OR] = 1.380, 95% CI = 1.128–1.687, p = .002; replication: OR = 1.231, 95% CI = 1.007–1.504, p = .043). The homeostasis model assessment of insulin resistance was increased in participants carrying Ins/Ins alleles (p = .0452). Interestingly, the insertion allele increased the risk of T2DM in males but not in females (male discovery: OR = 1.528, 95% CI = 1.141–2.047, p = .004; replication: OR = 1.439, 95% CI = 1.083–1.911, p = .012; female discovery: OR = 1.218, 95% CI = 0.913–1.626, p = .18; replication: OR = 1.161, 95% CI = 0.871–1.548, p = .308).

Conclusion

The DDAH1: ‐396_‐395insGCGT insertion allele is associated with increased risk of T2DM in a gender‐dependent manner, affects males but not females.

Prehypertension increases the risk of atherosclerosis in drug-naïve Japanese patients with type 2 diabetes mellitus

Purpose

Hypertension is a risk factor of atherosclerotic diseases. However, the importance of prehypertension in Japanese patients with type 2 diabetes mellitus (T2DM) is controversial. The aim of this study was to examine association between prehypertension, hypertension and atherosclerosis in T2DM.

Methods

We recruited 179 Japanese patients with T2DM, who never took any medication for diabetes, hypertension, dyslipidemia, or atherosclerosis. Intima-media thickness (IMT) of common carotid artery was evaluated by high-resolution B-mode ultrasonography.

Results

Multiple regression analysis adjusted for age, duration of diabetes, body mass index, HbA1c, fasting C-peptide, triglyceride, HDL-cholesterol, LDL-cholesterol, and estimated glomerular filtration rate showed that systolic blood pressure (SBP), but not diastolic BP, was significantly and positively associated with maximum IMT (IMT-max), mean IMT, and plaque score (β = 0.28, p<0.001; β = 0.26, p = 0.047; and β = 0.25, p = 0.006, respectively). ROC analysis showed that the cut-off value of SBP to detect atherosclerosis (IMT-max 1.8mm, the mean of IMT-max of this subjects) was 133.5 (p = 0.008), while DBP was not useful to detect it (p = 0.433). Then, participants were categorized as normotension (SBP <119 mmHg), prehypertension (SBP 120–139 mmHg), and hypertension (>140 mmHg). Multiple logistic regression analysis adjusted for the variables described above plus gender and smoking showed that prehypertension and hypertension were significantly associated with the increased risk of atherosclerosis [prehypertension; odds ratio (OR) 3.45, 95% confidence interval (CI) 1.11–10.76, p = 0.033, and hypertension; OR 7.29, 95%CI 1.99–26.78, p = 0.003].

Conclusion

These findings suggest that prehypertension categorized by SBP is an important risk factor of atherosclerosis independently of conventional risk factors in patients with T2DM.

Asymmetric dimethylarginine levels and diabetes duration: Relationship with measures of subclinical atherosclerosis and cardiac function in children and adolescents with Type 1 diabetes

AIMS

We aimed to evaluate asymmetric dimethylarginine levels in young patients with Type 1 diabetes mellitus according to diabetes duration and to examine the relationship between these levels and measures of atherosclerosis and myocardial function.

MATERIALS AND METHODS

In total, 83 patients (8.5-22 years) with Type 1 diabetes mellitus were stratified by diabetes duration: 12-60 months (Group 1, n = 27), >60-120 months (Group 2, n = 29) and >120 months (Group 3, n = 27). Asymmetric dimethylarginine levels were assessed. Carotid intima-media thickness was measured. Myocardial function was assessed by M-mode, conventional Doppler and tissue Doppler echocardiography.

RESULTS

Asymmetric dimethylarginine level was significantly higher in Group 1, while carotid intima-media thickness was significantly greater in Group 3 ( p < 0.05). Tissue Doppler echocardiography showed the ratio of peak early to peak late diastolic myocardial annular velocity decreased significantly in Groups 2 and 3 with a negative correlation with duration (r: -0.310, p = 0.004) and HBA1c levels (r = -0.391, p < 0.001). Myocardial performance index in all groups and isovolumic relaxation time in Group 3 increased significantly. Asymmetric dimethylarginine levels were negatively correlated with carotid intima-media thickness and isovolumic relaxation time ( p < 0.05).

CONCLUSION

In contrast to adult diabetics, asymmetric dimethylarginine concentration decreases as diabetes duration increases in young Type 1 diabetic patients and is associated with worsening measures of cardiovascular risk and poorer diastolic function.

Asymmetric dimethylarginine and symmetric dimethylarginine prospectively relates to carotid wall thickening in black men: the SABPA study

The relationship of both asymmetric (ADMA) and symmetric (SDMA) dimethylarginine with carotid wall thickness is inconclusive especially among black populations. We aimed to compare carotid intima media thickness (cIMT) and dimethylarginine levels in 75 black and 91 white men at baseline and after a 3-year follow-up, and to investigate associations of percentage change in cIMT with percentage change in dimethylarginine levels (ADMA and SDMA). Plasma levels of ADMA and SDMA were determined with a liquid chromatography mass spectrometry method and B-mode ultrasonography was used to determine the cIMT at baseline and follow-up. In black men, mean cIMT (p = 0.79) and ADMA levels (p = 0.67) remained the same, but SDMA levels were lower (p < 0.001) when comparing baseline and follow-up. In white men, cIMT increased (p < 0.001), but both mean ADMA and SDMA levels decreased (p < 0.001) over time. In black men, percentage change in cIMT was positively associated with percentage change in ADMA (R ² = 0.49; β = 0.46; p < 0.001) and percentage change in SDMA (R ² = 0.46; β = 0.41; p < 0.001). These associations were absent in the white men. Despite lower mean SDMA and similar ADMA and cIMT in black men, percentage change in cIMT was independently associated with percentage change in ADMA and percentage change in SDMA. These results suggest an important role for ADMA and SDMA lowering strategies to delay carotid wall thickening, especially in black populations prone to the development of cardiovascular disease.

Serum asymmetric dimethylarginine and arginine levels predict microvascular and macrovascular complications in type 2 diabetes mellitus

BACKGROUND

Increased oxidative stress in diabetes increases nitric oxide (NO) oxidation and low l-arginine (Arg) could further reduce NO and impair vascular function, thereby accelerating, in the long run, vascular complications. We therefore measured Arg and asymmetric dimethylarginine (ADMA) levels in patients with type 2 diabetes mellitus (T2DM) and healthy controls. Additionally, we observed the diabetic individuals over time to see if Arg and asymmetric dimethylarginine predicted T2DM complications.

METHODS

We examined baseline serum Arg and ADMA levels in a cohort of 105 participants with type 2 diabetes and compared them with an age- and weight-matched nondiabetic group of 137 individuals who served as a reference population. Additionally, we assessed whether Arg and/or ADMA predicted macrovascular and microvascular complications over 6 years of follow-up.

RESULTS

Serum Arg was lower in individuals with T2DM than in controls (64 ± 28 vs 75 ± 31 μmol/L; P = .009) and inversely related to hemoglobin A1c (r = -0.2; P = .002). Over follow-up, we observed that participants with T2DM in the lowest quartile of Arg had increased risk for the subsequent evolution of nephropathy, peripheral neuropathy, and composite microvascular complications (odds ratio [OR] = 5.5; 95% confidence interval [CI] -1.9 to 16; P = .002). The highest ADMA quartile was associated with increased risk for both microvascular (OR = 4.5; 95% CI -1.4 to 14.1; P = .009) and 6.5-year incident macrovascular complications (OR = 8.3; 95% CI 1.9-35.5; P = .004).

CONCLUSION

l-Arginine levels are lower in individuals with T2DM than in matched controls. Both low Arg and high ADMA, independent of each other and adjusted for classical risk factors, predict the incidence of microvascular complications.

Asymmetric dimethylarginine, a biomarker of cardiovascular complications in diabetes mellitus

Cardiovascular (CV) complications are an essential causal element of prospect in diabetes mellitus (DM), with carotid atherosclerosis being a common risk factor for prospective crisis of coronary artery diseases and/or cerebral infarction in DM subjects. From another point of view, asymmetric dimethylarginine (ADMA) has been established as an inhibitor of endogenous nitric oxide synthesis and the relationship between ADMA and arteriosclerosis has been reported. In our study with 87 type 2 DM (T2DM) patients, we have examined whether ADMA and other CV risk factors are the useful predictors of DMCV complications. After the measurement of the respective CV risk factors, we have followed the enrolled T2DM patients for 5 years. We have finally analyzed 77 patients. DMCV complications developed in 15 cases newly within 5 years, and 4 cases recurred. The concentrations of ADMA in plasma were markedly more elevated in 19 DM patients with CV complications than in 58 DM patients without CV complications. Urinary albumin (U-Alb), mean intimal-medial thickness (IMT) and ankle brachial index (ABI) were also higher in patients with CV complications. Multiple regression analyses showed that U-Alb had an influence on the high level of ADMA (standardized β = 6.59, P = 0.00014) independently of age, systolic BP, fibrinogen, mean IMT, plaque score, and ABI. The review indicates what is presently known regarding plasma ADMA that might be a new and meaningful biomarker of CV complications in DM subjects.

The effects of breastfeeding on serum asymmetric dimethylarginine levels and body composition in children

INTRODUCTION

The purpose of this work was to investigate the association of serum asymmetric dimethylarginine (ADMA) and high-sensitivity C-reactive protein (hs-CRP) levels with duration of breastfeeding and body composition in children.

PATIENTS AND METHODS

The study group consisted of 88 patients with a median age of 12 months (42 boys, 46 girls), classified as never breastfed or fully breastfed. ADMA and hs-CRP were measured by immunoenzymatic enzyme-linked immunosorbent assay commercial kits. Body composition analysis was performed by bioelectrical impedance.

RESULTS

We found significantly higher serum ADMA levels but not serum hs-CRP levels in never breastfed compared with the fully breastfed group (p<0.05). Serum ADMA was inversely associated with high-density lipoprotein-cholesterol levels and breastfeeding duration (p<0.05). Positive correlation was found between ADMA and body fat mass (p<0.05).

CONCLUSIONS

In never breastfed children, increased ADMA is observed; however, further studies are needed to assess whether breastfeeding duration affects body fat and body composition at older ages.

Plasma arginine/ADMA ratio as a sensitive risk marker for atherosclerosis: Shimane CoHRE study

BACKGROUND

Asymmetric dimethylarginine (ADMA), which acts an endogenous inhibitor of nitric oxide synthase (NOS), is involved in the pathogenesis of cardiovascular disease. Arginine (Arg) may regulate vascular endothelial function, since Arg is the substrate of NO competing with ADMA. In our previous study, low Arg/ADMA ratio is an independent risk for microangiopathy-related cerebral damage.

PURPOSE

Here, we performed a cross-sectional study to evaluate the association between the Arg/ADMA ratio and the maximal intima-media thickness (IMT) in the carotid artery.

SUBJECTS AND METHODS

Participants were 785 community-dwelling Japanese people without any severe disorders. Plasma concentration of Arg and ADMA in fasting blood sample was determined using HPLC. IMT was measured in the bilateral carotid artery by ultrasonography.

RESULTS

Among quartiles stratified by the Arg/ADMA ratio, ANOVA showed a significant difference in IMT and the IMT in Q1 (the lowest quartile) was significantly higher than that in Q4 (the highest quartile). In multiple linear regression analysis, age, the male gender, lower BMI, the presence of hypertension and lower Arg/ADMA ratio were independently correlated with IMT, while IMT was not correlated with Arg or ADMA alone. In addition, the Arg/ADMA ratio was associated with IMT independent of age, sex, BMI and the presence of hypertension with odds ratio 0.21 (95%CI: 0.05-0.88) in multiple logistic regression analysis for IMT 1.5 mm or more.

CONCLUSION

Imbalance of Arg and ADMA is independently involved in the progression of atherosclerosis, and the Arg/ADMA ratio may be a sensitive marker for atherosclerosis.

Asymmetric dimethylarginine and long-term adverse cardiovascular events in patients with type 2 diabetes: relation with the glycemic control

Background and aims

Elevated plasma asymmetric dimethylarginine (ADMA) levels have been observed in patients with insulin resistance and diabetes, and have been reported to predict adverse cardiovascular events in type 2 diabetic patients. However, the relationship between ADMA and glycemic control in patients with type 2 diabetes remained controversial.

Methods and results

We evaluated 270 patients with type 2 diabetes and measured their plasma ADMA and hemoglobin A1c (HbA1c) levels by high performance liquid chromatography. The mean age was 67 ± 12 years. The mean plasma ADMA and HbA1c level were 0.46 ± 0.09 μmol/l and 7.8 ± 1.6%, respectively. There was no significant correlation between plasma ADMA level and HbA1c level (r = −0.09, p = 0.13). During the median follow-up period of 5.7 years (inter-quartile range: 5.0 − 7.3 years), major adverse cardiovascular event (MACE, including cardiovascular death, myocardial infarction and stroke) was observed in 55 patients (20.4%). Multivariate Cox regression analysis revealed that the ADMA tertile was an independent risk factor for MACE (ADMA tertile III versus ADMA tertile I: p = 0.026, HR: 2.31, 95% CI: 1.10 − 4.81). The prognosis predictive power of ADMA disappeared in patients with well glycemic control (HbA1c ≤6.5%), and the ADMA-HbA1c interaction p value was 0.01.

Conclusions

In patients with type 2 diabetes, ADMA might be an independent risk factor for long-term adverse cardiovascular events. However, ADMA was not correlated with serum HbA1c level, and in diabetic patients with HbA1c ≤6.5%, elevated ADMA level was no longer associated with increased risk of long-term prognosis. Our findings suggested that the prognosis predictive value of ADMA in type 2 diabetes might be modified by the glycemic control.

Serum Asymmetric Dimethylarginine, and Adiponectin as Predictors of Atherosclerotic Risk among Obese Egyptian Children

BACKGROUND: Obesity is associated with an increased risk of developing hyperinsulinemia, dyslipidemia, hypertension, premature atherosclerosis, and coronary artery disease in the future.AIM: This study is designed to assess the relationship between serum adiponectin, asymmetric dimethylarginine (ADMA), and lipid profile among Egyptian overweight and obese children.METHODS: This cross sectional case control study included 40 selected pre-pubertal overweight and obese children, 24 girls (60%) and 16 boys (40%) aged between 5 to 13 years (8.85 ± 2.7 years), from new cases attending the National nutrition institute clinic during 2013. Forty apparently healthy children of matched age and sex were recruited as a control group.RESULTS: Obese group showed highly significant higher levels of serum ADMA, triglycerides, and total cholesterol compared with healthy controls (P <0.000 in all). However, serum adiponectin levels were highly significant lower in obese children compared to healthy controls (P < 0.000). Serum ADMA showed significant positive correlations with height, serum total cholesterol and serum triglycerides levels and significant negative correlation with the body mass index and weight for age z score.  Serum adiponectin showed significant negative correlations with BMI, weight, and weight for age z score and significant positive correlation with serum triglycerides. By linear regression analysis; serum adiponectin, and serum triglycerides levels were significant predictors of high serum ADMA level (p =0.045 and 0.015 respectively). BMI, weight, height and serum triglycerides were significant predictors of low serum adiponectin levels (p = 0.005, 0.022, 0.026 and 0.015 respectively).CONCLUSIONS: Our results revealed that ADMA, Adiponectin and lipid profile can be considered as predictive biomarkers in prediction and prevention of atherosclerotic risk in the future among overweight and obese Egyptian children.

Asymmetric and symmetric dimethylarginine in adolescents with hyperuricemia

The purpose of this work was to investigate if in adolescents with hyperuricemia serum levels of asymmetric and symmetric dimethylarginine (ADMA, SDMA) are increased and if their levels correlate with serum uric acid (UA). Patients and Methods. The study group consisted of 58 hyperuricemic patients aged median 16.15 Q1–Q3 (14–17). The reference group contained 27 healthy individuals with normal serum UA level. ADMA and SDMA were measured by immunoenzymatic ELISA commercial kits and expressed in μmol/L. Serum UA was measured by the colorimetric method. Results. In hyperuricemic patients serum ADMA values did not differ between two estimated groups (P > 0.05); however, SDMA was significantly higher than in reference group (P < 0.01). Serum ADMA and SDMA correlated positively with UA (r = 0.34, P < 0.01) (r = 0.31, P < 0.01) and hs-CRP (r = 0.20, P < 0.05) (r = 0.36, P < 0.01), respectively. Conclusion. We demonstrated increased SDMA but not ADMA levels in adolescents with hyperuricemia and their correlation with serum uric acid levels. However, at the moment it is difficult to answer the question if it is just coexistence of these factors or any mechanism linking uric acid and methylated arginines really exists.

Statin use in patients with diabetes and kidney disease: the Japanese experience

Diabetes is a leading cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD) in developed nations, including Japan and the United States. Japan has the unenviable distinction of having one of the world's highest rates of dialysis: in 2011, there were over 300,000 dialysis patients (2,383 per million people), with diabetic patients accounting for almost half of all incident cases. Concomitance of CKD and diabetes predicts a greater risk of cardiovascular disease (CVD) than either condition in isolation. Hence, appropriate management of modifiable cardiovascular (CV) risk factors, including dyslipidemia, is paramount in this high-risk group. The United States and Japan have distinct approaches to cholesterol management, with more stringent therapeutic targets for lipid control advocated in US guidelines. However, upward trends in cholesterol levels and coronary heart disease incidence in Japan may provide justification for more intensive CV risk factor management strategies by Japanese physicians to achieve maximum benefit. Attainment of recommended lipid goals in Japan is poor, particularly in patients with diabetes and/or CKD in whom CV risk factors are often undertreated. Statin therapy has been shown to be safe and effective in reducing CV risk in patients with diabetes and/or CKD stages 1-5. Moreover, statins may impart a renoprotective effect by preventing or delaying progressive loss of kidney function. This review summarizes evidence from studies in Western and Japanese populations to highlight the CV and renal benefits of lipid-lowering agents in CKD patients, including those with diabetes.

Association of circulating levels of asymmetric dimethylarginine (ADMA) with carotid intima-media thickness: evidence from 6168 participants

BACKGROUND

Epidemiologic investigations have linked the circulating levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), to carotid intima-media thickness (IMT). However, these studies result in various extent of relation between ADMA and IMT, the conclusions were inconsistent, and the precise relationship is therefore under debate. The objective of this systematic review and meta-analysis is to provide an overview of the relevant studies evaluating the association of levels of ADMA with carotid IMT and to gain more robust estimate of the relationship.

METHODS

Studies were identified through PubMed, Cochrane Library, Embase, reviews, and reference lists of relevant papers. Weighted means of the correlation coefficient (R) and partial correlation coefficient (PR) were calculated for relations by using random-effect models.

RESULTS

22 studies with a total of 6168 subjects were included in our meta-analysis. In an overall pooled estimate of correlation coefficient (R), levels of ADMA were significantly related to carotid IMT (pooled R: 0.29; 95% confidence interval [CI]: 0.20-0.38, P<0.001). Pooled estimate of partial correlation coefficient (PR) also resulted in a significant association of ADMA with carotid IMT (pooled PR: 0.21; 95% CI: 0.14-0.29; P<0.001). Furthermore, subgroup analysis found that the relation between ADMA and IMT was stronger in patients with chronic kidney diseases (CKDs) than that in subject with normal renal function.

CONCLUSIONS

Circulating levels of ADMA were positively related to carotid IMT, especially in patients with CKDs. The findings need confirmation in longitudinal and interventional studies.

Asymmetric dimethylarginine and carotid atherosclerosis in Type 2 diabetes mellitus

BACKGROUND

Circulating asymmetric dimethylarginine (ADMA) concentration is elevated in patients with Type 2 diabetes mellitus (T2DM).

AIM

To assess the relationship between plasma ADMA concentration and carotid atherosclerosis in patients with T2DM.

SUBJECTS AND METHODS

A total of 72 newly diagnosed and untreated T2DM individuals and 72 healthy controls were studied. Carotid atherosclerosis was determined by ultrasonographically evaluated intima- media thickness (IMT) and plaque score. Plasma concentration of ADMA was measured by high-performance liquid chromatography.

RESULTS

Plasma ADMA, mean IMT, and plaque score were higher in diabetic patients compared with controls. Univariate and multivariate analyses demonstrated an independent association between ADMA and mean IMT in diabetic patients. On a multiple logistic regression analysis, ADMA was the sole predictor of carotid plaque formation (plaque score ≥1.1) (odds ratio 2.43, 95% confidence interval 1.19 to 4.94, p<0.05).

CONCLUSION

Our results suggest that increased levels of ADMA might be involved in the development of carotid atherosclerosis in T2DM.

Relationship between adipocytokines and cardiovascular risk factors in patients with type 2 diabetes mellitus

The aim of this study was to explore the relationship between serum profiles of adiponectin, leptin, resistin and visfatin and traditional and non-traditional cardiovascular risk factors in patients with type 2 diabetes mellitus (T2DM). A total of 85 patients with T2DM and 30 non-diabetic controls were enrolled in the study. Levels of adipocytokines (adiponectin, leptin, resistin and visfatin), lipids (total cholesterol, triglycerides), lipoproteins [HDL-cholesterol, LDL-cholesterol, lipoprotein (a)], apolipoproteins (Apo-A1 and Apo-B), non-traditional cardiovascular risk markers [asymmetric dimethylarginine (ADMA), homocysteine] and the inflammatory marker hs-CRP were measured, and anthropometric variables were determined. Serum adiponectin levels were decreased and leptin, resistin and visfatin levels were increased in T2DM patients compared to controls. They were associated with obesity (BMI), insulin resistance (HOMA-IR) and various markers of glucose/lipid profile, inflammation and endothelial dysfunction markers. These results suggest that decreased serum adiponectin and increased leptin, resistin and visfatin levels in T2DM may be novel biochemical risk factors for cardiovascular complications.

Pioglitazone delays proximal tubule dysfunction and improves cerebral vessel endothelial dysfunction in normoalbuminuric people with type 2 diabetes mellitus

AIM

The renal and cerebral protective effects of pioglitazone were assessed in normoalbuminuric patients with type 2 diabetes mellitus (DM).

METHODS

A total of 68 normoalbuminuric type 2 DM patients were enrolled in a one-year open-label randomized controlled trial: 34 patients (pioglitazone-metformin) vs. 34 patients (glimepiride-metformin). All patients were assessed concerning urinary albumin: creatinine ratio (UACR), urinary alpha1-microglobulin, urinary beta2-microglobulin, plasma asymmetric dymethyl-arginine (ADMA), GFR, hsC-reactive protein, fibrinogen, HbA1c; pulsatility index, resistance index in the internal carotid artery and middle cerebral artery, intima-media thickness in the common carotid artery; cerebrovascular reactivity was evaluated through the breath-holding test.

RESULTS

At 1 year there were differences between groups regarding ADMA, urinary beta2-microglobulin, urinary alpha1-microglobulin, parameters of inflammation, serum creatinine, GFR, UACR, the cerebral haemodynamic indices. Significant correlations were found between alpha 1-microglobulin-UACR (R(2)=0.143; P=0.001) and GFR (R(2)=0.081; P=0.01); beta2-microglobulin-UACR (R(2)=0.241; P=0.0001) and GFR (R(2)=0.064; P=0.036); ADMA-GFR (R(2)=0.338; P=0.0001), parameters of inflammation, HbA1c, duration of DM, cerebral indices. There were no correlations between ADMA-UACR, urinary alpha1-microglobulin and beta2-microglobulin.

CONCLUSION

Proximal tubule (PT) dysfunction precedes albuminuria and is dissociated from endothelial dysfunction in patients with type 2 DM. Pioglitazone delays PT dysfunction and improves cerebral vessels endothelial dysfunction in normoalbuminuric patients with type 2 DM.