Evaluation of endothelial function and arterial stiffness in obese individuals with insulin resistance

BACKGROUND

Obesity is associated with metabolic imbalance, including insulin resistance and endothelial dysfunction.

AIM

We aimed to evaluate clinical and vascular parameters in obese with or without insulin resistance.

METHODS

Participants ( n=39) were divided into two groups according to Homeostasis Model Assessment - Insulin Resistance lower (group 1) or higher (group 2) than 2.7. All patients were submitted to clinical, anthropometric, biochemical, vascular structure and endothelial function assessment.

RESULTS

The mean age (53±9 vs. 52±7 years, p=0.784) and body mass index (34.3±4.1 vs. 35.2±3.9 kg/m², p=0.464) were similar in both groups, and 74.4% were treated hypertensive subjects. Fasting glucose (84±7 vs. 97±18 mg/dl, p=0.004) and insulin (9.32±2.48 vs. 22.74±7.49 μU/ml, p<0.001) were higher in group 2. Group 2 presented lower HDL-cholesterol (59±14 vs. 42±12 mg/dl, p<0.001) and higher triglycerides (122±87 vs. 191±112 mg/dl, p=0.042) levels compared with group 1. HOMA-IR was correlated with abdominal circumference ( r=0.51, p=0.001), abdominal/hip ratio ( r=0.57, p<0.001) and triglycerides/HDL ratio ( r=0.53, p=0.001). Differences in brachial flow-mediated dilation did not reach statistical significance (10.2±6.2 vs. 7.9±4.7%, p=0.245). Carotid intima-media thickness, carotid-femoral pulse wave velocity (8.5±1.9 vs. 9.1±1.5 m/s, p=0.334) and central hemodynamic parameters were also similar between groups.

CONCLUSION

Obese individuals with insulin resistance have higher visceral adiposity associated with impaired glucose and lipid metabolism. Endothelial function and arterial stiffness were similar between the groups, perhaps because of antihypertensive treatment in most of these subjects.

Beneficial effects of acute trans-resveratrol supplementation in treated hypertensive patients with endothelial dysfunction

Endothelial dysfunction is a surrogate marker of cardiovascular risk. Resveratrol is known to improve endothelial function in animals, however, clinical trials are limited. We hypothesized that the acute trans-resveratrol supplementation improves endothelial function in treated hypertensive patients with endothelial dysfunction. Twenty-four hypertensive patients between 45 and 65 years-old with baseline endothelial dysfunction were enrolled in a randomized, cross-over, double-blind, placebo-controlled trial. Individuals received either a single dose of trans-resveratrol (300 mg) or placebo and were crossed-over after a one-week washout period. Blood pressure (BP) measurements, aortic systolic blood pressure (SBP) and brachial flow-mediated dilation (FMD) were performed before and 1.5 hours after the intervention. FMD was significantly increased in women (4.2 ± 0.5 vs 7.1 ± 1.3%, p = 0.026) but not in men (4.4 ± 0.9 vs 4.9 ± 0.8%, p = 0.588) in the trans-resveratrol group. There was no statistical difference between baseline and final values of brachial BP and also no changes in aortic SBP. Patients with higher low-density lipoprotein (LDL) cholesterol had better FMD response to trans-resveratrol than patients with lower LDL cholesterol (7.4 ± 1.2 vs 4.3 ± 1.0%, p = 0.004). Our study demonstrated that the acute supplementation of trans-resveratrol promoted an improvement in endothelial function, especially in women and those with higher LDL-cholesterol, despite no changes in BP. List of Abbreviation: Aix: augmentation index; AP: augmentation pressure; BP: blood pressure; BMI: body Mass Index; CVD: cardiovascular disease; FMD: flow-mediated dilation; FRS: Framingham Risk Score; HDL: high-density lipoprotein; LDL: low-density lipoprotein; NO: nitric oxide; SPSS: Statistical Package for Social Sciences; ROS: reactive oxygen species; SBP: systolic blood pressure; TG: triglycerides.

Assessment of the impact of changes in temperature in Biomphalaria glabrata (Say, 1818) melanic and albino variants infected with Schistosoma mansoni (Sambon, 1907)

Fluctuations in population density of planorbid hosts of S. mansoni are influenced by climatic factors. The knowledge about interference from changes in water temperature in these populations is an important aspect of the epidemiology of schistosomiasis. In this experiment, it is explored the influence of different temperatures on the development of Schistosoma mansoni in Biomphalaria glabrata melanic and albino variants. The results indicated an intrinsic relationship between temperature and development of the parasite in the intramollusc phase, independent of the pigmentation of the mantle of the molluscs. The higher the temperature, the shorter the period necessary for the development of the parasite was while the higher the mortality of infected mollusks. It is concluded that, in the presence of climate change, the increasement of temperature in cold and flooded regions may encourage the establishment of new foci of transmission of schistosomiasis by changing the geographic extent and extending the epidemiological transmission potential. In warm climates, higher temperatures, however, could compromise the transmission of the disease because of biological stress suffered by parasite and host. Under these conditions, it can result in the death of the parasite or a change in their ability to infect new host species of molluscs in new areas. Mantle pigmentation patterns in molluscs have not shown significant interference in the development of the parasite.

Host-parasite relationship between Biomphalaria amazonica (Paraense, 1966) and Schistosoma mansoni (Sambon, 1907)

Biomphalaria amazonica is a planorbid species considered a potential host of Schistosoma mansoni. It is widely distributed in the Neotropical zone, particularly in the North and Centre-West of Brazil and in the North of Bolivia. The aim of the present study was to determine the host-parasite relationship between B. amazonica and S. mansoni (BH and SJ strains). Specimens of B. amazonica and their snail-conditioned water were examined in terms of their ability to attract miracidia. The infectivity of the mollusks was determined by exposing them to 20 miracidia of both strains. Sporocyst development and amebocyte reactions were studied after each mollusk specimen was exposed to 100 miracidia. Although no cercariae were eliminated, specimens of B. amazonica proved capable of attracting 77% of the miracidia they were exposed to. Viable sporocysts with no amebocyte reaction were found 96 hours after the exposure to miracidia. These results indicate the susceptibility of B. amazonica to the BH and SJ strains of S. mansoni, and therefore demonstrate the importance of this planorbid species as a potential vector of the trematode in the areas where it occurs.

Allopurinol attenuates L-NAME induced cardiomyopathy comparable to blockade of angiotensin receptor

It is widely recognized that L-NAME exposed rats develop myocardial fibrosis and hypertrophy. The aim of this study was to evaluate the contribution of xanthine oxidase (XO) to these phenomena using allopurinol, isolated or associated with olmesartan. Thirty adult male Wistar rats were divided into 5 groups (n=6) and studied for 5 weeks: L group (L-NAME, 40mg/kg/day); L+A group (L-NAME and allopurinol, 40 mg/kg/day); L+O group (L-NAME and olmesartan, 15mg/kg/day); L+A+O group (L-NAME, allopurinol, and olmesartan); and control group. L-NAME caused arterial hypertension and cardiomyocyte hypertrophy. Hypertension was prevented by olmesartan, but not by allopurinol. There was an increase of left ventricular mass index in the L-NAME group that was prevented by allopurinol, olmesartan and by the combination of both. The increase in mean cardiomyocyte transversal area caused by L-NAME was prevented by the allopurinol and olmesartan combination, or by olmesartan used as monotherapy, but not by allopurinol alone. There was a reduction in the myocardial vascularization index caused by L-NAME which was abolished by allopurinol or by olmesartan, but not by the association. L-NAME caused a reduction in the total number of cardiomyocyte nuclei. This was prevented by olmesartan alone or associated with allopurinol, but not by allopurinol alone. We conclude that XO has an important contribution to adverse cardiac remodeling in L-NAME exposed animals. Moreover, allopurinol acts without interfering with L-NAME induced hypertension. The protective action of this drug is comparable to the results obtained with olmesartan. Antioxidative mechanisms are proposed to account for the pressure independent effects of allopurinol.

Humoral immune response of water buffalo monitored with three different antigens of Toxocara vitulorum

Humoral immune response of water buffalo naturally infected with Toxocara vitulorum was monitored using three different antigens of this parasite in serum and colostrum of buffalo cows and calves. Soluble extract (Ex) and excretory/secretory (ES) larval antigens and perienteric fluid antigen (Pe) of adult T. vitulorum were used to measure the antibody levels by an indirect ELISA. Serum of 7-12 buffalo cows for the first 365 days and colostrum of the same number of buffalo cows for the first 60 days of parturition, and serum of 8-10 buffalo calves for the first 365 days after birth were assayed. The ELISA detected antibodies against all three T. vitulorum antigens in the colostrum and serum of 100% of buffalo cows and calves examined. The highest antibody levels against Ex, ES and Pe antigens were detected in the buffalo cow sera during the perinatal period and were maintained at high levels through 300 days after parturition. On the other hand, colostrum antibody concentrations of all three antigens were highest on the first day post-parturition, but decreased sharply during the first 15 days. Concomitantly to the monitoring of immune response, the parasitic status of the calves was also evaluated. In calves, antibodies passively acquired were at the highest concentrations 24 h after birth and remained at high levels until 45 days coincidentally with the peak of T. vitulorum infection. The rejection of the worms by the calves occurred simultaneously with the decline of antibody levels, which reached their lowest levels between 76 and 150 days. Thereafter, probably because of the presence of adults/larvae stimulation, the calves acquired active immunity and the antibodies started to increase slightly in the serum and plateaued between the days 211 and 365. All three antigens were detected by the serum antibodies of buffalo calves; however, the concentration of anti-Pe antibody was higher than anti-EX and anti-ES, particularly after 90 days of age. By conclusion, the buffalo cows develop immunity and keep high levels of antibodies against T. vitulorum-Ex, ES and Pe antigens and these antibodies are transferred to their calves through the colostrum. This passively acquired immunity does not protect the calves against the acquisition of the infection, but these antibodies, passively or actively acquired, may have an important role during worm rejection by the calves and prevention of intestinal reinfection.

Aortopulmonary window and double aortic arch. A rare association

We report the case of a 27-year-old male patient with dyspnea on physical exertion. Clinical assessment and various tests led to the diagnosis of aortopulmonary window and double aortic arch. According to a literature search, this may be the first report on such association.

[Morphological changes in muscular arterial walls in hypertensive patients]

PURPOSE

To identify structural lesions in the wall of uterine arteries in hypertensive women.

METHODS

Twenty six patients who underwent an elective hysterectomy were selected and separated in two groups. Group 1 was formed by women with normal blood pressure and group 2 consisted of hypertensive patients without regular treatment. Two segments of the uterine artery were obtained from every patient shortly after surgery. The fragments were fixed, sliced and stained. The morphological study was carried out using optical microscopy.

RESULTS

Age was similar in both groups with means of 46.8 +/- 7.6 and 46.7 +/- 6.4 years-old in groups 1 and 2, respectively. The average maximal systolic and diastolic blood pressure during hospital admission were 130.0 +/- 3.4 and 83.8 +/- 6.5 mmHg in the control group and 163.8 +/- 4.3 and 105.8 +/- 9.9 mmHg in the hypertensive group (p < 0.0001). Hypertensive women had larger intimal thickness (p < 0.05). Elastic fibers were also more numerous and homogeneous in group 2. Cellular hypertrophy was more common in this group than in control patients (53.8% vs 23.1%).

CONCLUSION

Hypertension seems to accelerate the age-related increase in intima thickness. Hypertensive women have more numerous and homogeneous elastic fibers in the wall of the uterine artery. These findings indicate that hypertension may determine structural changes similar to vascular aging.

[Directional coronary atherectomy. The initial experience]

Four male patients, 38 to 59 years old (mean 49 +/- 2.5), with angina and the angiographic features has been the classical indications for the method, underwent directional coronary atherectomy. Vessels treated were, respectively, left anterior descending artery (LAD), right coronary artery (RCA), saphenous vein graft (SVG) to LAD and SVG to left marginal branch. Reductions to 50% or less of the internal diameter was considered a satisfactory result. Early success was obtained in all four patients. Obstructions of 75 to 95% (mean of 83 +/- 7.5%) were reduced to 0-25% (mean 12 +/- 5%) after atherectomy. Only one patient died suddenly five days after de procedure. So, directional coronary atherectomy may represent a reliable and safe method for special situations.

[Anatomical limitations for the performance of angioplasty in coronary multivessel disease]

PURPOSE

To study anatomical limitation of coronary angioplasty, as alternative therapy in patients with multivessel disease and submitted to bypass surgery.

METHODS

In 380 patients with multivessel disease and submitted to previous coronary bypass surgery, age ranged from 41 to 72 (average = 51) years, being 68% males. The following parameters were analyzed in the coronary arteriographies: anatomic aspects of the coronary arteries and distribution of the atherosclerotic stenosis. The patients were arranged in accordance to the criteria: complete revascularization, incomplete and no indication for coronary angioplasty.

RESULTS

The patients were arranged in 3 different groups: I-80 (21%) patients included those in whom complete revascularization would be possible; II--55 (14.5%) patients in whom only incomplete revascularization but satisfactory would be possible and III--245 (65.5%) those patients in whom coronary angioplasty would no have indication. The data referind the patients of groups I and II were analyzed together--135 (35.5%) and arranged according to the number of arteries involved. It was observed: two vessel disease--71.8%, three vessel--18.6% and 4 or more vessel--9.6%. In group III it was observed 51.0% of the patients with 3 or more vessel disease. The major factors to contra indicate coronary angioplasty in group III included: chronic coronary obstruction 99 (40.4%); diffuse disease 11 (4.5%); technical difficulties 10 (4.1%); left main coronary artery obstruction 5 (2%) or when two or more causes were combined 120 (49%).

CONCLUSIONS

Patients with multivessel disease and classic indication for coronary bypass surgery, have a basic limitation for angioplasty due to several anatomic factors. However, coronary angioplasty could be beneficial for a selected group of patients (35.5%) whenever a complete or incomplete revascularization could be obtained.