The effects of folic acid on markers of endothelial function in patients with type 1 diabetes mellitus

BACKGROUND

Endothelial dysfunction is considered as a fundamental and also preventable factor in the progression of vascular complications among type 1 diabetic patient. It occurs before the clinical manifestation of the mentioned complications. The aim of this study was to evaluate the effects of folic acid on endothelial function by measurements of adhesion molecules and von Willebrand factor (vWF) in patients with type 1 diabetes in Isfahan, Iran.

METHODS

This double blind, placebo-controlled crossover trial included type 1 diabetic patients aged 5-20 years old. Selected patients were randomized into two groups of A and B to receive folic acid 5 mg daily or placebo for 8 weeks. After a 2-week washout period, patients in the two groups were swapped to receive placebo or folic acid, respectively, for another 8 weeks. Blood and urine samples were taken to evaluate glycosylated hemoglobin (HbAlc), folic acid, vWF, intracellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), and microalbuminuria levels. Results of these measurements were compared in the two groups before and after folic acid and placebo administrations.

RESULTS

Fifty five type 1 diabetic patients aged 12.1 +/- 3.4 years with diabetes duration of 3.9 +/- 2.1 years were enrolled. Mean of folic acid level in the two studied groups was increased significantly (10.1 +/- 3.8 vs. 21.2 +/- 1.1 in group A and 15.5 +/- 1.9 vs. 19.9 +/- 2.8 in group B, p < 0.05). Mean of VCAM and microalbuminuria was decreased significantly after folic acid administration in the two groups (p < 0.05). Mean of HbA1c, ICAM and vWF did not significantly change after folic acid administration in the two groups (p > 0.05).

CONCLUSION

Folic acid administration decreased the level of endothelial dysfunction measured by adhesion molecules, especially VCAM and microalbuminuria. However, it did not significantly affect vWF. Further studies with larger sample size and long-term administration of folic acid are necessary for making precise decisions in this field. Key words: endothelial function, Diabetes Mellitus, folic acid.

The effect of Aloe vera leaf gel on fatty streak formation in hypercholesterolemic rabbits

BACKGROUND

Atherosclerosis is a complex disease that is associated with a variety of etiologic factors such as hyperlipidemia and inflammation. Aloe vera (Liliaceae family) has been used traditionally as an anti-inflammatory drug. The aims of this survey were to define the beneficial effects of Aloe vera leaf gel on some of the atherosclerosis risk factors, and also fatty streak formation in hypercholesterolemic rabbits.

MATERIALS AND METHODS

[corrected] 32 white male rabbits were randomly divided into four experimental groups (n = 8, each). During the study, the animals had a standard diet (control group), high cholesterol diet (HC group), high cholesterol diet with Aloe vera leaf gel (3.2%v/v) (HC+ Aloe group) and Aloe vera leaf gel (Aloe group) for 30 days. Fasting blood samples were collected from all animals at the beginning and end of the study. Then total cholesterol (TC), fasting blood sugar (FBS), triglyceride (TG) and CRP were measured before and after experimental periods. By the end of the study, the aortas were removed and investigated for atherosclerosis plaque formation.

RESULTS

Significant differences were observed in TC and CRP levels of the high-cholesterol diet with Aloe vera and the high-cholesterol diet alone (p < 0.05). The formation of fatty streaks in the aorta was also significantly lower in the same animals under the influence of dietary Aloe vera(p < 0.05). The control and Aloe group did not show any evidence of atherosclerosis. No significant difference was found between the groups in TG and FBS.

CONCLUSIONS

The data suggests that Aloe vera has beneficial effects on the prevention of fatty streak development; it may reduce the development of atherosclerosis through modification of risk factors. However, further studies are needed to understand the mechanisms whereby this plant exerts its anti-atherosclerotic effects.

Role of peroxisome proliferator-activated receptor β agonist on angiogenesis in hindlimb ischemic diabetic rats

INTRODUCTION

Studies indicated that PPARβ agonists play a role in modulation of angiogenesis. In this study, we evaluated the effect of specific PPARβ agonist, GW0742, on angiogenesis and serum vascular endothelial growth factor (VEGF), VEGF receptor-2 (VEGFR-2), and nitrite concentrations in hindlimb ischemia in normal and diabetic rats.

METHODS

Hindlimb ischemic rats were divided into four groups: control, diabetic, control, and diabetic treated with GW0742 (n=7 each). Diabetes was induced by injection of streptozotocin (55mg/kg, ip). GW0742 was injected 1day after surgery (1mg/kg, sc). After 21days, blood samples were taken, and gastrocnemius muscles were harvested for immunohistochemistry.

RESULTS

GW0742 significantly increased serum nitrite and VEGFR-2 concentrations and VEGF-to-VEGFR-2 ratio in control and diabetic rats. Capillary density was lower in diabetic animals compared to the control, and GW0742 significantly restored the capillary density in the control and diabetic hindlimb ischemic rats.

CONCLUSION

PPARβ agonists restore skeletal muscle angiogenesis and can be considered for prevention and/or treatment of peripheral vascular complications in diabetic subjects.

Interferon-beta-1b protects against multiple sclerosis-induced endothelial cells apoptosis

Disruption of the blood-brain-barrier (BBB) due to endothelial cell (EC) injury is an essential step in formation of multiple sclerosis (MS) lesions. We investigated the role of endothelial cell (EC) apoptosis in the pathophysiology of MS, studying the therapeutic effect of IFN-beta-1b against MS sera-induced endothelial apoptosis. Human umbilical vein endothelial cells were treated with sera from patients with active MS (in relapse), MS in remission, or sera from healthy volunteers (each n = 5). Apoptosis was assessed by annexin V-propidium iodide staining. Effects of IFN-beta-1b on EC apoptosis were tested at increasing doses (10, 100, and 1000 U/ml). Nitrite (NO₂-⁻) levels were determined in culture supernatants. EC apoptosis was increased by sera from exacerbating MS patients, but not remission, compared to healthy individuals (p less than 0.001). Effects were blocked by IFN-beta-1b at 10 U/ml (p less than 0.05), but not higher doses, and was associated with increased NO/NO₂- production (less than 0.05). EC apoptosis leading to disruption of the BBB may play a role in MS etiology and represents a novel therapeutic mechanism of action for IFN-beta-1b in MS therapy.

The effect of captopril on impaired wound healing in experimental diabetes

We aimed to investigate whether oral administration of captopril modulate wound healing, nitric oxide (NO), and vascular endothelial growth factor (VEGF) concentration in wound fluid of diabetic rats. 48 male Sprague-Dawley rats were divided in four groups (n = 12). The 36 rats were rendered diabetic by streptozotocin. The animals of the first and second groups received 25 and 50 mg/kg/day captopril, respectively, (DM-cap25 and DM-cap50). The animals of the third group were treated by distilled water (DM-control). Control rats had no intervention. The wound fluid level of NO and VEGF were measured. Wound specimens were investigated histopathologically. At the 5th day, there was significantly more NO(x) in wound fluid of DM-cap25 compared to other groups. At the 7th day, both captopril-treated groups had more NO(x) in wound fluid compared to other groups. At the 11th day, both captopril-treated groups had more NO(x) in wound fluid compared to DM-control group. VEGF concentration was significantly higher in both captopril-treated groups versus DM-control group (P < .05). There were significant higher wound healing scores in captopril-treated groups compared with DM-control group (P < .05). These results suggest that captopril might be useful in diabetic wound healing.

Interleukin-10 and Transforming Growth Factor-β in Early and Late Lesions of Patients with Leishmania major Induced Cutaneous Leishmaniasis

BACKGROUND

Cutaneous leishmaniasis is a neglected parasitic disease, which imposes massive human distress and financial costs to the endemic countries. Better understanding of host immune response to the parasite leads to helpful strategies for disease control. Interleukin (IL)-10 and transforming growth factor (TGF)-β are important immune regulatory cytokines, which appear to develop non-healing forms of leishmaniasis. However, there is little information about the function of IL-10 and TGF-β in old world cutaneous leismaniasis. The aim of this study was to analyze the role of IL-10 and TGF-β in human cutaneous leishmaniasis due to Leishmania major infection.

METHODS

Biopsies were obtained from lesions of twenty proven cases of L. major induced cutaneous leishmaniasis. IL-10 and TGF-β positive cells were detected by immunofluorescence staining of frozen sections and compared between two groups of patients with early and late lesions.

RESULTS

The mean percentage of IL-10 positive cells were significantly (P= 0.035) higher in late lesions (0.51±0.24) than early ones (0.15±0.07). Similar results were obtained for TGF-β with mean percentages of 0.16±0.05 and 0.53±0.28 in early and late lesions respectively (P= 0.008).

CONCLUSION

IL-10 and TGF-β are present in lesions of L. major induced cutaneous leishmaniasis and contribute to the pathogenesis of long lasting disease forms.

Circulating endothelial cells (CECs) and E-selectin: Predictors of preeclampsia

BACKGROUND

Circulating endothelial cells (CECs) and E-selectin are known as sensitive and specific markers of endothelial dysfunction. This study investigated whether CECs and E-selectin are surrogate biomarkers of preeclampsia and if measurement of CECs and E-selectin, early in the third trimester, could be a means of predicting preeclampsia.

METHODS

In this prospective, descriptive-analytic study, rollover test was performed on 523 pregnant women during 28-30 weeks of gestation. CECs were measured by anti-CD 146-driven immunomagnetic isolation in women with positive rollover test. They were followed up prospectively until delivery without any active intervention. Women with and without preeclampsia were determined. The number of CECs and level of E-selectin were compared in the two studied groups.

RESULTS

From the 47 pregnant women with positive rollover test who were selected and followed up, 22 individuals were diagnosed with preeclampsia while the remainder were normotensive. Mean CEC numbers was significantly higher in preeclamptic women than normal pregnancies (24.7 cells/mL vs. 13 cells/mL). The best cut-off point for CEC numbers was 6.5 with a sensitivity of 78.9% and a specificity of 69.1%. The level of E-selectin was significantly higher in mothers with preeclampsia (p < 0.05).

CONCLUSIONS

Higher levels of CECs and E-selectin in women with positive rollover test who developed preeclampsia prior to onset of the complication were predictive of preeclampsia. However, larger studies are needed to confirm these findings.

Interleukin-10 and Transforming Growth Factor-β in Early and Late Lesions of Patients with Leishmania major induced Cutaneous Leishmaniasis

BACKGROUND

Cutaneous leishmaniasis is a neglected parasitic disease, which imposes massive human distress and financial costs to the endemic countries. Better understanding of host immune response to the parasite leads to helpful strategies for disease control. Interleukin (IL)-10 and transforming growth factor (TGF)-β are important immune regulatory cytokines, which appear to develop non-healing forms of leishmaniasis. However, there is little information about the function of IL-10 and TGF-β in old world cutaneous leismaniasis. The aim of this study was to analyze the role of IL-10 and TGF-β in human cutaneous leishmaniasis due to Leishmania major infection.

METHODS

Biopsies were obtained from lesions of twenty proven cases of L. major induced cutaneous leishmaniasis. IL-10 and TGF-β positive cells were detected by immunofluorescence staining of frozen sections and compared between two groups of patients with early and late lesions.

RESULTS

The mean percentage of IL-10 positive cells were significantly (P= 0.035) higher in late lesions (0.51±0.24) than early ones (0.15±0.07). Similar results were obtained for TGF-β with mean percentages of 0.16±0.05 and 0.53±0.28 in early and late lesions respectively (P= 0.008).

CONCLUSION

IL-10 and TGF-β are present in lesions of L. major induced cutaneous leishmaniasis and contribute to the pathogenesis of long lasting disease forms.

Interferon-beta-1beta protects against multiple sclerosis-induced endothelial cells apoptosis

Disruption of the blood-brain-barrier (BBB) due to endothelial cell (EC) injury is an essential step in formation of multiple sclerosis (MS) lesions. We investigated the role of endothelial cell (EC) apoptosis in the pathophysiology of MS, studying the therapeutic effect of IFN-beta-1b against MS sera-induced endothelial apoptosis. Human umbilical vein endothelial cells were treated with sera from patients with active MS (in relapse), MS in remission, or sera from healthy volunteers (each n = 5). Apoptosis was assessed by annexin V-propidium iodide staining. Effects of IFN-beta-1b on EC apoptosis were tested at increasing doses (10, 100, and 1000 U/ml). Nitrite (NO₂-⁻) levels were determined in culture supernatants. EC apoptosis was increased by sera from exacerbating MS patients, but not remission, compared to healthy individuals (p less than 0.001). Effects were blocked by IFN-beta-1b at 10 U/ml (p less than 0.05), but not higher doses, and was associated with increased NO/NO₂- production (less than 0.05). EC apoptosis leading to disruption of the BBB may play a role in MS etiology and represents a novel therapeutic mechanism of action for IFN-beta-1b in MS therapy.

Von Willebrand factor, and soluble intercellular and vascular cell adhesion molecules as indices of endothelial activation in patients with congenital hypothyroidism

Considering the high prevalence of congenital hypothyroidism (CH) in Isfahan, the possible involvement of endothelial dysfunction in the pathogenesis of CH and the lack of studies in this field, the aim of this study was to determine the endothelial function in CH patients.

METHODS

During this case-control study, the endothelial function in CH neonates and in those with normal screening results was evaluated during a CH screening program in Isfahan. Peripheral blood samples were obtained for measurement of the von Willebrand factor (vWf), and intercellular and vascular cell adhesion molecule (ICAM and VCAM). In CH patients these biomarkers were measured twice: before and 4 weeks after treatment.

RESULTS

In this study, 56 neonates were evaluated: 30 of them were neonates with normal screening results and 26 were diagnosed with CH and classified into two groups according to their TSH levels. The mean ICAM and VCAM were higher in CH patients than in the control group (p < 0.05). The mean ICAM and VCAM decreased significantly after treatment in CH patients (p < 0.05). There is no significant relationship between TSH, ICAM, VCAM and vWf (p > 0.05).

CONCLUSION

The findings of this study demonstrate the possible involvement of the endothelial system in the pathogenesis of CH and its cardiovascular complications. Further studies with a larger sample size and with the measurement of other endothelial function markers are needed.

Relationship between echocardiographic findings and laboratory serum biomarkers in patients with and without low cardiac output

BACKGROUND

Cardiac dysfunction is seen in many patients and could be evaluated with echocardiography and serum biomarkers. The aim of this study was evaluation of the relationship between echocardiographic findings and laboratory serum biomarkers in children with and without low cardiac output.

METHODS

Thirty patients older than 1 month with and without low cardiac output were enrolled in this study. It composed of 13 patients with dilated cardiomyopathy (DCM), 7 with end stage renal disease (ESRD) and 10 who had a Fontan operation. Echocardiography was performed with emphasis on shortening fraction (SF) and ejection fraction (EF). Blood samples were collected for measurement of atrial natriuretic peptide (ANP), high sensitivity C-reactive protein (hs-CRP) and alkaline phosphatase (Alk-P). Both echocardiographic findings and laboratory data were compared with control levels in twenty-seven normal children. Pearson correlation and regression analysis were conducted to evaluate the aforementioned associations.

RESULTS

The mean of ANP and hs-CRP in the case group was statistically higher than control group (p < 0.001). The mean of ANP and hs-CRP were different in all groups (p < 0.001). There was a reverse linear regression between the SF and ANP in the case group (r = -0.594, p < 0.001).

CONCLUSIONS

Determination of the plasma ANP and hs-CRP level may be helpful for decisions related to early diagnosis of patient with low cardiac output.

Air pollution and hospitalization for respiratory diseases among children in isfahan, iran

BACKGROUND

Adverse effects of urban air pollution on human health notably the paediatric age group is of great importance. Limited data exist from developing countries. This study investigates the hospitalization of children because of respiratory diseases and air pollution levels in Isfahan, the second large city in Iran.

METHODS

Hospital admission data were collected retrospectively from 120 randomly selected respiratory patients in Pediatric wards from the main referral hospital in Isfahan from March 2005-2006, and simultaneous air pollution data were collected from two monitoring stations located in south and north parts of the city.

RESULTS

The result of statistical modeling using generalized linear Poisson regression showed that PM(10) and sulfur dioxide (SO(2)) concentrations had statistically significant positive association with number of respiratory admissions of children.

CONCLUSION

This study confirms the findings of previous studies about the association of air pollutants' levels with hospitalization because of respiratory diseases in young children. Air pollution continues to pose a threat to public health notably in the paediatric age group, and underscores the need to re-examine national environmental health policies and standards in developing countries.

Genetic variation in the association of air pollutants with a biomarker of vascular injury in children and adolescents in Isfahan, Iran

BACKGROUND

Some experimental studies revealed that exposure to air pollution increases the expression of tissue factor (TF) in atherosclerotic lesions. We aimed to investigate the role of TF +5466A>G (rs3917643) polymorphism in the association of air pollution on serum levels of TF as a biomarker of vascular injury in children.

METHODS

This cross-sectional study was conducted among 110 children, consisting of 58 (52.8%) girls and 52 (47.2%) boys with a mean age of 12.7 ± 2.3 years, living in Isfahan, Iran. Enzyme-linked immunosorbent assay were used for measurement of serum TF. Genotype of +5466A>G (rs3917643) polymorphism was determined by the polymerase chain reaction-restriction length fragment polymorphism (PCR-RFLP) method.

RESULTS

We identified 2 individuals with +5466AG genotype and 108 homozygous for the +5466A allele (no +5466GG homozygotes). The mean pollution standards index (PSI) value was at moderate level, the mean particular matter measuring up to 10 μm (PM(10)) was more than twice the normal level. Multiple linear regression analysis showed that after adjustment for confounding factors (weight status, dietary and physical activity pattern), serum TF level had significant relationship with PSI (beta: 0.55, SE: 0.07, p<0.000) and PM(10) (beta: 0.51, SE: 0.03, p=0.001).

CONCLUSIONS

In spite of similar genetic polymorphism of TF, air pollutants might have an independent association with systemic inflammatory and coagulation responses. The harmful effects of air pollutants on the first stages of atherosclerosis in the pediatric age group should be underscored in primordial and primary prevention of chronic diseases.

The effects of bare metal versus drug-eluting stent implantation on circulating endothelial cells following percutaneous coronary intervention

BACKGROUND

The purpose of this study was to compare the effects of bare metal stents (BMS) and drug-eluting stents (DES) implantation on circulating endothelial cells (CECs) which have been proposed as cellular markers of endothelial dysfunction following percutaneous coronary intervention (PCI). Recently, it has been established that DES further reduce restenosis and revascularization rate compared to bare metal stents in elective procedures. However, its benefits are compromised by the stent-related thrombosis events.

METHODS

22 patients who were candidate of PCI were included in this study. The patients underwent DES implantation (n = 11) or BMS implantation (n = 11). In all patients the numbers of CECs were determined before and a week after stent implantation using flow cytometry and the obtained data were compared within and between groups by paired and unpaired Student's t-test, respectively. CECs were defined as cells negative for CD45 (FITC) and highly double positive for CD146 (PE) and CD34 (PE-Cy5) expression.

RESULTS

There were no significant differences in the baseline levels of CECs between two groups (p = 0.96). Stent implantation led to a significant increase in CECs compared with the preprocedural levels in the BMS group (p = 0.005) whereas there was a significant decrease in CEC numbers in DES group (p < 0.001). One week after stent implantation CECs count in BMS group was significantly higher compared to DES group (p < 0.001).

CONCLUSIONS

The results indicate that patients undergoing DES implantation were subjected to less endothelial injury than patients receiving BMS as indicated by CEC enumeration.

Enalapril improves endothelial function in patients with migraine: A randomized, double-blind, placebo-controlled trial

BACKGROUND

There are increasing evidences of endothelial dysfunction in migraine. The ACE-inhibitors have previously been shown to be effective in migraine prophylaxis. Furthermore, ACE inhibitors have beneficial effects on endothelial dysfunction. We therefore investigated whether Enalapril is effective in endothelial function improvement.

METHODS

In this randomized clinical trial, 10 mg Enalapril daily was compared with matched placebo in 40 patients with migraine for two months. Flow Mediated Dilation (FMD), serum total nitrite and C-reactive protein (CRP) were measured in all patients at the baseline and after 2 months.

RESULTS

patients' FMD increased in the case group after treatment with Enalapril (p = 0.002) while there was no significant change in control group. Total nitrite concentration increased in case group (p = 0.000), while there was no significant difference before treatment. There was no significant difference in the CRP concentrations in two groups.

CONCLUSIONS

These results indicate that ACE inhibition can improve endothelial function in patients with migraine, as it has been shown by both FMD and serum levels of nitric oxide. The mechanism could be either that Enalapril limits the angiotensin IIinduced production of superoxide radicals which would normally inactivate nitric oxide, or that it may increase bradykinin-mediated nitric oxide release.

Effects of diabetes on myocardial capillary density and serum angiogenesis biomarkers in male rats

INTRODUCTION

Cardiovascular disease is one of the main causes of mortality and morbidity in diabetic patients. This study evaluated the effects of diabetes on myocardial capillary density and several serum angiogenic factors including nitric oxide, vascular endothelial growth factor, and soluble vascular endothelial growth factor receptors.

METHODS

Twelve male rats were divided into two groups: control and diabetic (n = 6 each). Diabetes was induced with a single dose of streptozotocin (50 mg/kg). After 21 days, capillary density in the myocardial tissue was evaluated using immunohistochemical staining and is reported as capillaries per mm². Blood samples were collected before and after the induction of diabetes.

RESULTS

In the diabetic group, serum nitric oxide and soluble vascular endothelial growth factor receptor 2 concentrations were lower than the levels in the control group, while the level of soluble vascular endothelial growth factor receptor 1 was significantly higher. There was no significant change in the serum vascular endothelial growth factor concentration between the diabetic and control groups; however, the ratio of vascular endothelial growth factor to vascular endothelial growth factor receptor 1 was significantly lower in the diabetic animals. The myocardial capillary density was also lower in the diabetic group compared with the control group (1549 ± 161 vs. 2156 ± 202/mm², respectively).

CONCLUSION

Reduced serum nitric oxide and vascular endothelial growth factor receptor 2 levels, increased serum vascular endothelial growth factor receptor 1 levels and a lower vascular endothelial growth factor to vascular endothelial growth factor receptor 1 ratio may be responsible for the decreased myocardial capillary density in diabetic rats.

The effects of cardiac tertiary prevention program after coronary artery bypass graft surgery on health and quality of life

OBJECTIVES

Cardiac tertiary prevention programs intend to support the recovery course following coronary artery bypass grafting (CABG). We investigated the effects of attendance at cardiac rehabilitation (CR) programs following CABG on patients' mortality, morbidity and health related quality of life.

METHODS

Eighty patients who underwent CABG were selected in a way that half of them had attended a cardiac rehabilitation program and the other half had not. Health related quality of life (HRQoL) was measured using the Short Form 36 (SF-36) questionnaire at a mean of 23.4 months postoperatively. Severity of cardiac symptoms on the basis of the New York Health Association (NYHA), the occurrence of any neurological symptoms, hospitalization and restoration of patients to their previous level of performance in social activities were assessed after CABG surgery.

RESULTS

There were no deaths. There were no differences in postoperative NYHA scores, neurological symptoms, and hospitalization. Three of the eight health domains measured by SF-36, namely general health (P = 0.010), physical function (P = 0.002), and mental health (P < 0.001), showed significantly better values for attendants than non-attendants. Rehabilitation participants returned to their previous level of performance in social activities more than their control counterparts.

CONCLUSIONS

Higher general health scores (SF-36) were associated with attendance at CR programs. The findings of this study provide rationale to consider a broader scope of physiological and psychosocial parameters to predict outcomes of CABG surgery.

Early prevention by L-Arginine attenuates coronary atherosclerosis in a model of hypercholesterolemic animals; no positive results for treatment

Background

Endothelial dysfunction (ED) is an independent predictor of cardiovascular events. ED is also a reversible disorder, and nitric oxide donors like L-arginine may promote this process. Despite the positive results from several studies, there are some studies that have shown that L-arginine administration did not improve endothelium-dependent dilation or the inflammatory state of patients. In this study the early and the late effects of L-arginine on coronary fatty streak formation and ED biomarkers were considered in hypercholesterolemic rabbits.

Methods

36 white male rabbits randomly assigned in 3 groups. Rabbits were fed 1% high-cholesterol diet (LP group, n = 15), or high-cholesterol diet with oral L-arginine (3% in drinking water) (EP group, n = 15) or standard diet (control group, n = 6) for 4 weeks (phase I). Afterward, all animals were fed normal diet for 4 weeks (phase II). In the second phase, L-arginine was discontinued for EP group and was begun for LP group. The plasma levels of lipids, von Willebrand factor (vWF), and nitrite were compared before and after 4 and 8 weeks of experiment. Coronary fatty streak formation was measure after 4 and 8 weeks of experiment.

Results

The plasma levels of lipids were increased significantly in both groups of LP and EP after phase I. The hypercholesterolemia induced significant increased vWF release in LP group. The L-arginine supplementation led to significant plasma nitrite increment in EP group. The vWF in LP group was higher than other groups (p < 0.05). By the end of phase II, despite of start of L-arginine supplementation for LP group and L-arginine discontinuation in EP group, there were significantly more fatty streaks lesions in LP group coronary arteries than EP group. Furthermore, L-arginine supplementation did not result in significant nitrite increment in LP group.

Conclusion

Early prevention by L-arginine may be helpful to prevent the ED, but our study did not suggest the treatment. It seems reasonable to consider ED-aside from control the cardiovascular risk factors in primary prevention of atherosclerosis and its clinical outcomes before development of irreversible vascular damage.

L-arginine supplementation influenced nitrite but not nitrate and total nitrite in rabbit model of hypercholesterolemia

BACKGROUND

The assessment of altered nitric oxide (NO) availability is of potentially important diagnostic and prognostic significance. The present study is aimed to investigate the effect of L-arginine (as a natural NO donor) supplementation on NO metabolite in a rabbit model of hypercholesterolemia to find a reliable marker for endothelial NO production.

METHODS

White male rabbits (n = 30) randomly assigned to 2 groups. Rabbits were fed 1% high-cholesterol diet (HC group, n = 15), or HC diet with oral L-arginine (3% in drinking water) (HC + L-arginine group, n = 15) for 4 weeks. The serum levels of lipids, L-arginine, total NO metabolites (NOx), nitrite and nitrate were measured before and after the study.

RESULTS

In this study, L-arginine supplementation led to a significant increased plasma level of L-arginine. The serum level of nitrite was significantly higher in L-arginine treated group while serum level of nitrate and NOx was significantly lower than HC group.

CONCLUSION

As the result of our study showed, nitrite is a useful marker of endogenous endothelial NO production and although frequently used, neither nitrate nor NOx are reliable markers of acute changes in endothelial NO synthase activity.