Vascular dysfunction programmed in male rats by topiramate during peripubertal period.

AIM: The present study evaluated whether topiramate (TPM) treatment during the peripubertal period affects vascular parameters of male rats and whether oxidative stress plays a role in these changes. MAIN METHODS: Rats were treated with TPM (41 mg/kg/day, gavage) or vehicle (CTR group) from the postnatal day (PND) 28 to 50. At PND 51 and 120 the rats were evaluated for: thoracic aorta reactivity to phenylephrine, in the presence (Endo+) or absence of endothelium (Endo-), to acetylcholine and to sodium nitroprusside (SNP), aortic thickness and endothelial nitric oxide synthase (eNOS) expression. In serum were analyzed: the antioxidant capacity by ferric reducing antioxidant power assay; endogenous antioxidant reduced glutathione, and superoxide anion. Results were expressed as mean ± s.e.m., differences when p < 0.05. STATISTICS: Two-way ANOVA (and Tukey's) or Student t-test. KEY FINDINGS: At PND 51, the contraction induced by phenylephrine in Endo+ ring was higher in TPM when compared to CTR. At PND 120, the aortic sensitivity to acetylcholine in TPM rats was reduced in comparison with CTR. The aortic eNOs expression and the aortic thickness were similar between the groups. At PND 51 and 120, TPM group presented a decrease in antioxidants when compared to CTR groups and at PND 120, in TPM group the superoxide anion was increased. SIGNIFICANCE: Taken together, the treatment of rats with TPM during peripubertal period promoted permanent impairment of endothelial function probably mediated by oxidative stress.

High prevalence of food insecurity, the adverse impact of COVID-19 in Brazilian favela.

OBJECTIVE: To investigate food insecurity (FI) prevalence in two favelas in Brazil in the early weeks of the social distancing policy, from 27 March 2020 to 1 June 2020. DESIGN: A cross-sectional study using an online questionnaire to elicit information on socio-economic and demographic characteristics, the types of stores visited to buy food, and FI screening. The FI experience was evaluated according to the Brazilian Food Insecurity Scale. Factors associated with moderate or severe FI were investigated using the logistic regression model. SETTING: São Paulo city, Brazil. PARTICIPANTS: Totally, 909 householders. RESULTS: Eighty-eight per cent of the households included young women working as cleaners or kitchen assistants and in sales services. One-fifth of the participants were involved in the federal cash transfer programme, called Bolsa Família. There were 92 % households with children. The most frequent experience reported was uncertainty about food acquisition or receiving more (89 %), eating less than one should (64 %), not being able to eat healthy and nutritious food (46 %), and skipping a meal (39 %). Forty-seven per cent of the participants experienced moderate or severe FI. Factors associated with moderate and severe FI were low income, being a Bolsa Família recipient, having a low level of education and living in a household without children. CONCLUSIONS: Half of the participants experienced moderate or severe FI, and almost 10 % experienced hunger. Our data suggest that families with children were at a lower risk of moderate to severe FI. It is possible that nationally established social programmes such as Bolsa Família were protecting those families.

Body Mass Index and Cardiovascular Risk Factors in Children and Adolescents with High Birth Weight.

BACKGROUND/AIMS: This study aimed to identify a possible association among high birth weight with overweight/obesity, high arterial blood pressure, dyslipidemia, and insulin resistance in children and adolescents. METHODS: This is a cross-sectional study with 719 children and adolescents (6-12 years) stratified according to birth weight (low birth weight [LBW] <2,500 g, adequate birth weight [ABW] 2,500-3,999 g, and high birth weight [HBW] ≥4,000 g). Data collected were anthropometric data, arterial blood pressure levels, lipid profile, and insulin resistance (fasting glucose and insulin, used to calculate homeostatic model assessment-IR). RESULTS: The mean age of schoolchildren was 9.5 ± 2.0 years and 371 (51.6%) were male. LBW and HBW were observed in 79 of 719 (10.9%) and 40 of 719 (55.6%) children/adolescents, respectively. There was no increased risk of overweight (OR 0.9; 95% CI 0.4-2.1; p = 0.964) and obesity (OR 1.4; 95% CI 0.6-3.5; p = 0.588) in HBW group compared to LBW and ABW groups. HBW was not associated with high blood pressure, dyslipidemia, and insulin resistance. The LBW group was independently associated with higher values of systolic (OR 1.07; 95% CI 1.05-1.10; p < 0.01) and diastolic blood pressure (OR 1.04; 95% CI 1.00-1.07; p = 0.044). CONCLUSION: There was no association between HBW with overweight/obesity and classic cardiovascular risk factors in this group of children/adolescents. Only LBW was related to higher blood pressure levels.

Intrauterine undernutrition in rats interferes with leukocyte migration, decreasing adhesion molecule expression in leukocytes and endothelial cells.

Experimental and epidemiologic data have shown that malnutrition predisposes individuals to infections. Immune responses are compromised, particularly in undernourished children. Therefore, we investigated the migratory capacity of leukocytes, using the intravital microscopy technique, in male Wistar rats (8-9 wk of age) that were undernourished in utero after their dams were fed 50% less food than the amount consumed by control dams. The number of leukocytes rolling along the venular endothelium, sticking after stimulation with leukotriene B4, tumor necrosis factor-alpha (TNF-alpha) or zymosan-activated plasma, or migrating after TNF-alpha stimulation was significantly reduced in the undernourished rat offspring. Compared with nourished rat offspring, undernourished offspring had significantly reduced numbers of circulating leukocytes, higher blood pressure, and higher leukocyte rolling velocity (V(WBC)), as well as a higher ratio between V(WBC) and RBC velocity (V(RBC)). Endothelial P-selectin and intercellular adhesion molecule-1 (ICAM-1) expression, analyzed by immunohistochemistry, and basal leukocyte L-selectin expression, analyzed by flow cytometry, were significantly reduced in the undernourished rat offspring. Because the groups did not differ in leukocyte CD11/18 expression, endothelial expression of platelet-endothelial cell adhesion molecule-1, or venular blood flow velocity and, consequently, venular shear rate, we conclude that intrauterine undernutrition in rats reduces leukocyte migration, downregulates endothelial expression of P-selectin and ICAM-1, as well as leukocyte expression of L-selectin, while reducing leukocyte counts. The higher V(WBC) and V(WBC)/V(RBC) ratio may also play a role in this reduced leukocyte migration. Our data suggest that this phenomenon is involved in the increased predisposition to infections in undernourished subjects.

Tetrahydrobiopterin improves endothelial dysfunction and vascular oxidative stress in microvessels of intrauterine undernourished rats.

In the present study, we investigated the effects of the exogenous application of tetrahydrobiopterin on the endothelium-dependent vasorelaxation and superoxide anion generation in the mesenteric microvessels of intrauterine undernourished rats. In addition, we investigated the presence of peroxynitrite in these rats by evaluation of nitrotyrosine-containing proteins, a stable end-product of peroxynitrite oxidation. For this, female pregnant Wistar rats were fed either normal or 50% of the normal intake diets during the whole gestational period. Male offspring (16 weeks of age) were studied to assess microvascular reactivity, superoxide production using a hydroethidine staining assay, nitric oxide synthase (NOS) activity and nitric oxide (NO) production. Western blot analysis was used to quantify nitrotyrosine-containing proteins and relative multiplex RT-PCR analysis for endothelial NOS (eNOS) mRNA expression. Superfusion with tetrahydrobiopterin significantly decreased superoxide generation and improved vascular function. Intrauterine malnutrition induced a decrement of NOS activity and NO production without affecting the gene expression of eNOS. However, incubation with tetrahydrobiopterin significantly improved NO production after stimulation with acetylcholine or bradykinin in intrauterine undernourished rats. The fact that the nitrotyrosine-containing proteins were increased could, at first sight, suggest that the peroxynitrite is the mediator responsible for the excessive oxidation and depletion of tetrahydrobiopterin. Our study shows that exogenous application of tetrahydrobiopterin leads to a significant improvement of endothelium-dependent vasodilatation, enhanced NO production and decreased superoxide generation in microvessels of intrauterine undernourished rats. Since we found a decrease in NOS activity without an alteration in the gene expression of eNOS, we suggest that impaired NOS-dependent responses of mesenteric arterioles are related to the impairment of tetrahydrobiopterin pathways.

Gender differences in superoxide generation in microvessels of hypertensive rats: role of NAD(P)H-oxidase.

OBJECTIVE: This study is aimed to explore whether gender plays a role in the generation of nitric oxide (NO) and superoxide anion (O(2)(-)) in microvessels of hypertensive rats (SHR), as well as the potential mechanisms involved in these effects. METHODS AND RESULTS: NO generation in mesenteric arterioles was evaluated by measuring NO synthase (NOS) activity and protein expression. Oxidative stress was studied in vivo in mesenteric arterioles from male and female SHR by hydroethidine microfluorography. Although we did not observe any sex-related differences in NO generation, we found that hydroethitine oxidation is markedly increased (30.9+/-2.4%) in male compared to female (12.3+/-2.5%; p<0.05), demonstrating a gender difference in O(2)(-) production. The treatment of mesenteries with DPI (NAD(P)H-oxidase inhibitor) and treatment of SHR with losartan [Angiotensin-II type 1 (AT-1) receptor antagonist] markedly reduced O(2)(-) production in male, while produced a minor effect in female, suggesting that overexpression/activity of AT-1 receptor and NAD(P)H-oxidase contribute for the sexual dimorphism in superoxide generation. Immunoblot analyses provide evidences of overexpression of the NAD(P)H-oxidase components p22(phox), gp91(phox), p47(phox) and p67(phox) in arterioles from male in comparison to female. Losartan treatment inhibited the overexpression of these subunits in male, without affecting the responses in female. CONCLUSION: Taken together, our findings demonstrate that male SHR presents higher superoxide anion concentration under basal condition than does female. An AT-1-dependent overexpression of the NAD(P)H-oxidase components may account for the sexual dimorphism in oxidative stress, and may play an important role in the noted gender differences on incidence of cardiovascular disease.

Relative contribution of estrogen withdrawal and gonadotropins increase secondary to ovariectomy on prostaglandin generation in mesenteric microvessels.

Recent studies have established that ovariectomy impairs endothelial function, partially by increasing vasoconstrictor prostaglandins generation. Because ovariectomy causes concomitant lack of estrogen and increase of gonadotropins (ie, LH and FSH), in this study we explored the relative role of estrogen and LH/FSH in modulating vasoconstrictor prostaglandins generation in mesenteric arteriolar bed of SHR. Endothelium-dependent relaxation to acetylcholine (ACh) and bradykinin (Bk) was markedly reduced in ovariectomized (OVX) compared with SHR in physiological estrus (OE). Estrogen replacement (OVX + E), but not the decrease in LH/FSH levels with leuprolide (OVX + Leu), corrected the altered vasorelaxation response in OVX. Treatment of mesenteries with diclofenac, prostaglandin-H synthase (PGHS) inhibitor, significantly enhanced the relaxing response in arteries from OVX and OVX + Leu, but not those from OE, indicating that a PGHS-derived vasoconstrictor has modified the endothelium-dependent response during estrogen but not LH/FSH deprivation. Confirming these data, in response to exogenous arachidonic acid, whereas arteries from OVX and OVX + Leu exhibited a marked and similar vasoconstrictor response, the arteries from OE and OVX + E rats exhibited a slight vasodilation. We also demonstrated by RT-PCR that ovariectomy significantly increased PGHS-2 but not PGHS-1 mRNA expression in comparison to OE. The PGHS-2 overexpression in OVX was corrected by estrogen replacement, but not by the reduction of LH/FSH levels. Altogether these data strongly support a role for hypoestrogenism rather than LH/FSH enhancement, associated with the removal of ovaries, in the increase of vasoconstrictor prostaglandins, possibly by a mechanism involving PGHS-2 overexpression.

NADPH oxidase and enhanced superoxide generation in intrauterine undernourished rats: involvement of the renin-angiotensin system.

OBJECTIVE: We previously reported that intrauterine undernutrition increased the oxidative stress by decreasing superoxide dismutase activity. In the present study, we tested whether NADPH oxidase, xanthine oxidase, cyclooxygenase or nitric oxide synthase are responsible for the increased O(2)(-) generation observed in rats submitted to intrauterine undernutrition. In addition, we investigated the effect of angiotensin II (ANG II) on O(2)(-) production via activation of NADPH oxidase. METHODS: Female pregnant Wistar rats were fed either normal or 50% of the normal intake diets, during the whole gestational period. At 16 weeks of age, the rats were used for the study of intravital fluorescence microscopy; microvascular reactivity, local ANG II concentration and AT(1), p22(phox) and gp91(phox) gene expression. In this study only the male offspring was used. RESULTS: Treatment of mesenteric arterioles with the xanthine oxidase inhibitor oxypurinol, the nitric oxide synthase inhibitor L-NAME or the cyclooxygenase inhibitor diclofenac did not significantly change superoxide production. Thus, these vascular sources of superoxide were not responsible for the increased superoxide concentration. In contrast, treatment with the NADPH oxidase inhibitor apocynin significantly decreased superoxide generation and improved vascular function. On the other hand, intrauterine undernutrition did not alter the gene expression for p22(phox) and gp91(phox). The fact that the local ANG II concentration was increased and the attenuation of oxidative stress by blocking AT(1) receptor with losartan, led us to suggest that ANG II induces O(2)(-) generation in intrauterine undernourished rats. CONCLUSION: Our study shows that NADPH oxidase inhibition attenuated superoxide anion generation and ameliorated vascular function in rats submitted to intrauterine undernutrition. Although it is not clear which mechanisms are responsible for the increase in NADPH oxidase activity, a role for ANG II-mediated superoxide production via activation of NADPH oxidase is suggested.

Vitamins C and E improve endothelial dysfunction in intrauterine-undernourished rats by decreasing vascular superoxide anion concentration.

Epidemiological studies suggest that intrauterine undernutrition plays an important role in the development of arterial hypertension in adulthood. Ascorbic acid (vitamin C) and alpha-tocopherol (vitamin E) have antioxidant properties that could improve redox-sensitive vascular changes associated with hypertension. The authors determined whether vitamins C and E treatments ameliorate the hypertension and vascular function in male rats submitted to intrauterine undernutrition. Pregnant Wistar rats were fed either normal or 50% of the normal intake diets during the whole gestational period. At 14 weeks of age, male offspring of nutritionally restricted dams were divided into 3 subgroups: vehicle-treated (vehicle for 15 days, by gastric gavage, n = 9), vitamin C-treated (ascorbic acid, 150 mg/Kg/d for 15 days, by gastric gavage, n = 15) and vitamin E-treated (alpha-tocopherol, 350 mg/kg per day for 15 days, by gastric gavage, n = 15). Systolic blood pressure was determined before and after antioxidant treatments by the tail-cuff method. At 16 weeks of age, the rats were used for the study of microvascular reactivity and intravital fluorescence microscopy. Intrauterine undernutrition induced hypertension, and vitamins C or E treatments reduced the blood pressure levels. The decreased acetylcholine and bradykinin-induced vasodilation was restored in the vitamin-treated rats. These effects were associated with decreased vascular superoxide anion concentration. The results show that vitamins C and E reduce oxidative stress and high blood pressure levels, and improve vascular function in intrauterine-undernourished rats.

Intrauterine undernutrition: expression and activity of the endothelial nitric oxide synthase in male and female adult offspring.

OBJECTIVE: Epidemiological studies suggest that intrauterine undernutrition plays an important role in the development of arterial hypertension in adulthood. In an attempt to define the mechanisms whereby blood pressure may be raised, we have hypothesized that arteries from offspring of nutritionally restricted dams exhibit abnormalities in the endothelial function and in nitric oxide synthesis. In order to investigate the existence of potential gender differences on the effects of intrauterine undernutrition, both male and female offspring of pregnant Wistar rats on normal and restricted diets were studied in adulthood. METHODS: Female pregnant Wistar rats were fed either normal or 50% of the normal intake diets, during the whole gestational period. At 14 weeks of age, the rats were used for the study of vascular reactivity, eNOS and iNOS gene expression, eNOS activity and, in the case of females, estrogen levels. RESULTS: Intrauterine undernutrition induced hypertension in both male and female offspring, but hypertension was more severe in male rats. Endothelium-intact aortic rings from male and female rats in the restricted diet group exhibited increased responses to norepinephrine, decreased vasodilation to acetylcholine and unaltered responses to sodium nitroprusside in comparison to aortic rings from control rats. No gender-related differences were observed in the vascular reactivity studies. Intrauterine undernutrition promoted decreased gene expression for eNOS in aorta isolated from male, but not female, offspring, reduction in eNOS activity in both male and female offspring and impairment in synthesis of estrogen in female offspring. CONCLUSION: Our data show that intrauterine undernutrition: (1) induces hypertension both in the male and female offspring, hypertension being more severe in male than in female rats; (2) alters endothelium-dependent responses in aortas from the resulting offspring. The endothelial dysfunction is associated with a decrease in activity/expression of eNOS in aortas from male offspring. The mechanism involved in altered response to ACh in female offspring might be a consequence of reduction in estrogen levels leading to reduced eNOS activity.

Enhanced oxidative stress as a potential mechanism underlying the programming of hypertension in utero.

Maternal undernutrition during critical periods of organ development is known to impair fetal growth and predispose to the development of adulthood diseases, such as hypertension, coronary heart disease and type II diabetes that are linked to low birth weight and are characterized by endothelial dysfunction. Increased oxidative stress, in rats submitted to intrauterine undernutrition, provides a potential explanation for the endothelial dysfunction development. The aim of this study was to determine the oxidative stress and its consequence on mesenteric arteriolar responses to vasoactive agents in offspring from diet-restricted dams. For this, female pregnant Wistar rats were fed either normal or 50% of normal intake diets, during the whole gestational period. In male offspring, arterial blood pressure was determined by the tail cuff method in anesthetized rats, mesenteric arteriolar reactivity and superoxide anion generation were studied using intravital microscopy and superoxide dismutase activity was determined in mesentery by spectrophotometric assay. Intrauterine undernutrition induced hypertension, decreased vasodilation to acetylcholine and bradykinin but did not alter the responses to sodium nitroprusside. Topical application of superoxide dismutase and superoxide dismutase mimetic manganese (III) tetrakis (1-methyl-4-pyridyl) porphyrin significantly improved the altered arteriolar responses to acetylcholine and bradykinin. A decreased superoxide dismutase activity and an increased superoxide anion concentration were observed in the offspring of diet-restricted dams. This study shows for the first time that intrauterine undernutrition enhances oxidative stress in vivo and relates this to the impaired endothelium-dependent vasodilation.

Severe nutritional restriction in pregnant rats aggravates hypertension, altered vascular reactivity, and renal development in spontaneously hypertensive rats offspring.

Epidemiologic studies suggest that intrauterine undernutrition plays an important role in the development of arterial hypertension in adulthood. The aim of the current study was to evaluate whether severe nutritional restriction during pregnancy can aggravate hypertension, vascular reactivity changes, and renal development in spontaneously hypertensive rat (SHR) offspring. To investigate the potential existence of gender differences, both male and female offspring of pregnant SHRs on a restricted diet were studied in adulthood. Female pregnant SHRs were fed either normal or 50% of the normal intake diets, during the whole gestational period. Arterial blood pressure and nephron number were determined. Norepinephrine, acetylcholine, and sodium nitroprusside responses in isolated aortic rings from the offspring (male and female, when they reached adulthood) were also evaluated. In the SHR offspring (male and female) the intrauterine undernutrition further increased the blood pressure levels, increased the response to norepinephrine, and decreased the response to acetylcholine, without altering the response to sodium nitroprusside. In addition, it induced a decrease in the number of nephrons in the kidney from adult offspring. In conclusion, fetal undernutrition aggravates hypertension and the endothelial dysfunction along with an impairment of renal development in both male and female SHRs.