DNA damage and repair on hematopoietic stem cells: impact of oxidative stress in renovascular hypertension.

BACKGROUND: This study investigated oxidative damage to bone marrow cells in the pathogenesis of renovascular hypertension (RH). METHODS: Male C57BL/6 J mice (10-week-old and ~23 g) were divided into two groups: Sham-operated and 2K1C, which has a stainless-steel clip placed around the left renal artery. After twenty-eight days, the animals were anesthetized for hemodynamic measurements and bone marrow cells isolation. The intracellular production of ROS, DNA damage, and DNA repair kinetics were evaluated. RESULTS: Our results show that RH increases HSCs ROS production and that the 2K1C group showed a significant reduction of HSCs in the G0/G1 phase, increased p53 expression, DNA fragmentation, low DNA repair capacity, and a higher percentage of apoptotic cells when compared with the Sham group. CONCLUSIONS: Our data imply that RH can compromise the hematopoiesis by increased oxidative stress leading to impaired DNA repair activity. Furthermore, this study provides new insights into the influence of hypertension on bone marrow homeostasis. This study showed for the first time that RH leads to oxidative damage, including genotoxic, to bone marrow cells. Thus, these findings provide new insights into the consequences of RH on bone marrow cells.

Optimal Parameters of Laser Therapy to Improve Critical Calvarial Defects.

Body bones play diverse pivotal roles, including the protection of vital organs. For instance, the integrative functions of the brain controlling diverse peripheral actions can be affected by a traumatic injury on the calvaria and the reparative process of a large defect is a challenge in the integrative physiology. Therefore, the development of biomaterials and approaches to improve such defects still requires substantial advances. In this regard, the most attractive approaches have been covering the cavity with inorganic bovine bone (IBB) and, more recently, also using low-level laser therapy (LT), but this issue has opened many questions. Here, it was determined the number of LT sessions required to speed up and to intensify the recovery process of two 5-mm-diameter defects promoted in the calvaria of each subgroup of six adult Wistar rats. The quantitative data showed that 30 days post-surgery, the recovery process by using blood clot-filling was not significantly influenced by the number of LT sessions. However, in the IBB-filled defects, the number of LT sessions markedly contributed to the improvement of the reparative process. Compared to the Control group (non-irradiated), the percentage of mineralization (formation of new bone into the cavities) gradually increased 25, 49, and 52% with, respectively, 4, 7, and 11 sessions of LT. In summary, combining the use of IBB with seven sessions of LT seems to be an optimal approach to greatly improve the recovery of calvarial defects. This translational research opens new avenues targeting better conditions of life for those suffering from large bone traumas and in the present field could contribute to preserve the integrative functions of the brain.

Benefits of multi-day supplementation with probiotic kefir in Rasmussen encephalitis: the first case report.

INTRODUCTION: Rasmussen encephalitis (RE) is a rare inflammatory disease, characterized by unilateral hemispheric atrophy, focal intractable seizures, progressive hemiparesis, and neurological deficits. CASE REPORT: The patient is a young man under pharmacotherapy for epilepsy, exhibiting classical abnormal movements, which are consider typical hallmarks of RE. During clinical care sessions, he presented many episodes of tonic-clonic seizures involving sudden loss of consciousness followed by a post-ictal phase with weakness and interaction difficulty. During the kefir supplementation, the patient presented only short-term absence seizures, quickly returning to activities. Additionally, he presented cognitive and language improvement, being more responsive to commands. The daily diary control of patient's mother and caregiver at school reported an impressive reduction in number and severity of seizures, becoming less aggressive and more involved in school activities. The serum biochemical markers showed that kefir administration caused a significant decrease of pro-inflammatory and a simultaneous increase of anti-inflammatory cytokine levels. In parallel, after treatment, this probiotic reduced reactive oxygen species levels, increased NO bioavailability, revealing antiapoptotic and antigenotoxic effects. Regarding the microbiological analysis, kefir increased Lactobacillus and Bifidobacterium species. CONCLUSION: To our knowledge, this is the first case reporting remarkable beneficial effects of the probiotic kefir in RE. This case report strongly suggests kefir supplementation as a potential and safe-effective adjuvant therapeutic strategy in the control and treatment of RE.

The Emerging Scenario of the Gut-Brain Axis: The Therapeutic Actions of the New Actor Kefir against Neurodegenerative Diseases.

The fact that millions of people worldwide suffer from Alzheimer's disease (AD) or Parkinson's disease (PD), the two most prevalent neurodegenerative diseases (NDs), has been a permanent challenge to science. New tools were developed over the past two decades and were immediately incorporated into routines in many laboratories, but the most valuable scientific contribution was the "waking up" of the gut microbiota. Disturbances in the gut microbiota, such as an imbalance in the beneficial/pathogenic effects and a decrease in diversity, can result in the passage of undesired chemicals and cells to the systemic circulation. Recently, the potential effect of probiotics on restoring/preserving the microbiota was also evaluated regarding important metabolite and vitamin production, pathogen exclusion, immune system maturation, and intestinal mucosal barrier integrity. Therefore, the focus of the present review is to discuss the available data and conclude what has been accomplished over the past two decades. This perspective fosters program development of the next steps that are necessary to obtain confirmation through clinical trials on the magnitude of the effects of kefir in large samples.

Subchronic and Low Dose of Tributyltin Exposure Leads to Reduced Ovarian Reserve, Reduced Uterine Gland Number, and Other Reproductive Irregularities in Female Mice.

Tributyltin (TBT) chloride is an endocrine disrupting chemical associated with reproductive complications. Studies have shown that TBT targets the reproductive tract, impairing ovarian folliculogenesis, and uterine morphophysiology. In this investigation, we assessed whether subchronic and low dose of TBT exposure results in abnormal ovarian follicular reserve and other irregularities in female mice. TBT was administered to female mice (500 ng/kg/day for 12 days via gavage), and reproductive tract morphophysiology was assessed. We further assessed reproductive tract inflammation and oxidative stress. Improper functioning of the reproductive tract in TBT mice was observed. Specifically, irregular estrous cyclicity and abnormal ovarian morphology coupled with reduction in primordial and primary follicle numbers was observed, suggesting ovarian reserve depletion. In addition, improper follicular development and a reduction in antral follicles, corpora lutea, and total healthy ovarian follicles together with an increase in cystic follicles were apparent. Evidence of uterine atrophy, reduction in endometrial gland number, and inflammation and oxidative stress were seen in TBT mice. Further, strong negative correlations were observed between testosterone levels and primordial, primary, and total healthy ovarian follicles. Thus, these data suggest that the subchronic and low dose of TBT exposure impaired ovarian follicular reserve, uterine gland number, and other reproductive features in female mice.

Sildenafil reduces aortic endothelial dysfunction and structural damage in spontaneously hypertensive rats: Role of NO, NADPH and COX-1 pathways.

Arterial hypertension is a condition associated with endothelial dysfunction, accompanied by an imbalance in the production of reactive oxygen species (ROS) and NO. The aim of this study was to investigate and elucidate the possible mechanisms of sildenafil, a selective phosphodiesterase-5 inhibitor, actions on endothelial function in aortas from spontaneously hypertensive rats (SHR). SHR treated with sildenafil (40 mg/kg/day, p.o., 3 weeks) were compared to untreated SHR and Wistar-Kyoto (WKY) rats. Systolic blood pressure (SBP) was measured by tail-cuff plethysmography and vascular reactivity was determined in isolated rat aortic rings. Circulating endothelial progenitor cells and systemic ROS were measured by flow cytometry. Plasmatic total antioxidant capacity, NO production and aorta lipid peroxidation were determined by spectrophotometry. Scanning electron microscopy was used for structural analysis of the endothelial surface. Sildenafil reduced high SBP and partially restored the vasodilator response to acetylcholine and sodium nitroprusside in SHR aortic rings. Using selective inhibitors, our experiments revealed an augmented participation of NO, with a simultaneous decrease of oxidative stress and of cyclooxygenase-1 (COX-1)-derived prostanoids contribution in the endothelium-dependent vasodilation in sildenafil-treated SHR compared to non-treated SHR. Also, the relaxant responses to sildenafil and 8-Br-cGMP were normalized in sildenafil-treated SHR and sildenafil restored the pro-oxidant/antioxidant balance and the endothelial architecture. In conclusion, sildenafil reverses endothelial dysfunction in SHR by improving vascular relaxation to acetylcholine with increased NO bioavailability, reducing the oxidative stress and COX-1 prostanoids, and improving cGMP/PKG signaling. Also, sildenafil reduces structural endothelial damage. Thus, sildenafil is a promising novel pharmacologic strategy to treat endothelial dysfunction in hypertensive states reinforcing its potential role as adjuvant in the pharmacotherapy of cardiovascular diseases.

Bisphenol A contamination in infant rats: molecular, structural, and physiological cardiovascular changes and the protective role of kefir.

The effects of bisphenol A (BPA) contamination on the cardiovascular function still are not clear. Here, we evaluated the vascular effects of BPA and the protective actions of kefir in infant rats. Animals (25 days old) were treated with BPA (100 µg/Kg/day) for 60 days (BPA group), or administered kefir (0.3 mL/100 g) in addition to BPA (BPA kefir group), compared with non-treated rats (Control group).The vascular endothelial function was evaluated in aortic rings through the relaxation response to acetylcholine and specific blockers. The balance between reactive oxygen species (ROS) and nitric oxide (NO) was assessed through flow cytometry in the vascular tissue. The BPA group developed high blood pressure (+10%) and the analysis of vascular reactivity showed an impaired ACh-induced relaxation (~80%). The further analysis by using NADPH, NOS and COX blockers revealed that the impaired vasorelaxation was due to increased ROS production (+12%), NO bioavailability (-12%) and increased vasoconstriction to prostanoids (+36%) compared with the Control group. Kefir treatment reverted those effects significantly. Analysis of the aortic cells showed increased •O2- production (1942±39 a.u.) and decreased NO bioavailability (1250±30 a.u.) compared with the Control group (1374±146 and 2777±25 a.u., P<.05) and kefir reverted these values (1298±57 and 2517±57 a.u.). Contamination by BPA in this model caused hypertension and endothelial dysfunction and it was accompanied by a vascular ROS/NO imbalance, damage of endothelial layer and pro-apoptotic effects. The novelty is that the treatment using probiotic kefir was able to attenuate the progression the above BPA effects.

Antioxidant effect of sildenafil: Potential hepatoprotection via differential expression of mitochondrial proteins in apolipoprotein E knockout mice.

BACKGROUND: High plasma cholesterol levels are able to trigger several pathophysiological events, including inflammation, cell damage and especially oxidative stress. Previously, studies have shown that sildenafil exhibited antioxidant effects in several experimental models. Here we evaluate the role of sildenafil in liver redox equilibrium of apolipoprotein E knockout (apoE-KO) mice. METHODS: ApoE-KO mice were divided in two groups: one group received the PDE5 inhibitor sildenafil (40 mg/kg/day) for 3 weeks (apoE-KO + Sil) and was compared to a second group of apoE-KO mice, which received only the vehicle (water) for 3 weeks (apoE-KO). Control group (C57 mice) received only a standard chow diet. At the age of 18 weeks, mice livers were collected for the measurement of intracellular ROS levels and apoptotic cells by flow cytometry analysis, and mitochondria isolation for proteomic analysis. RESULTS: Compared to the control group, liver cells from apoE-KO presented some typical redox imbalance features: higher levels of intracellular ROS (global oxidative stress ˜60%, superoxide anion ˜82%, and peroxynitrite/hydroxyl radical ˜53%), higher amounts of apoptotic cells (up to ˜19%) and higher mitochondrial intensity of catalase (+339%) and transferrin spots (+914%). After treatment with sildenafil, apoE-KO presented ROS levels and the number of apoptotic cells similar to those observed in C57. In addition, when compared to apoE-KO, apoE-KO + Sil showed lower spots volumes of catalase (-23%) and transferrin (-71%) and up-regulation of urate oxidase (+94%). CONCLUSION: The treatment with sildenafil is able to induce beneficial changes in liver mitochondrial protein dynamics, which restores the redox homeostasis contributing to a potential hepatoprotection.

Increased ROS production and DNA damage in monocytes are biomarkers of aging and atherosclerosis.

BACKGROUND: New evidence demonstrates that aging and dyslipidemia are closely associated with oxidative stress, DNA damage and apoptosis in some cells and extravascular tissues. However, in monocytes, which are naturally involved in progression and/or resolution of plaque in atherosclerosis, this concurrence has not yet been fully investigated. In this study, we evaluated the influence of aging and hypercholesterolemia on serum pro-inflammatory cytokines, oxidative stress, DNA damage and apoptosis in monocytes from apolipoprotein E-deficient (apoE-/-) mice compared with age-matched wild-type C57BL/6 (WT) mice. Experiments were performed in young (2-months) and in old (18-months) male wild-type (WT) and apoE-/- mice. RESULTS: Besides the expected differences in serum lipid profile and plaque formation, we observed that atherosclerotic mice exhibited a significant increase in monocytosis and in serum levels of pro-inflammatory cytokines compared to WT mice. Moreover, it was observed that the overproduction of ROS, led to an increased DNA fragmentation and, consequently, apoptosis in monocytes from normocholesterolemic old mice, which was aggravated in age-matched atherosclerotic mice. CONCLUSIONS: In this study, we demonstrate that a pro-inflammatory systemic status is associated with an impairment of functionality of monocytes during aging and that these parameters are fundamental extra-arterial contributors to the aggravation of atherosclerosis. The present data open new avenues for the development of future strategies with the purpose of treating atherosclerosis.

Beneficial Morphofunctional Changes Promoted by Sildenafil in Resistance Vessels in the Angiotensin II-Induced Hypertension Model.

BACKGROUND: By acting on multiple targets and promoting diverse actions, angiotensin II (Ang II) plays a pivotal role in vascular function. Recent studies suggested that phosphodiesterase-5 (PDE-5) inhibitors exhibit therapeutic effects in cardiovascular diseases. Here, the effects of sildenafil on vascular disturbances were analyzed in a mouse model of Ang II-induced hypertension. METHODS AND RESULTS: Male C57BL/6 mice were used as untreated animals (control) or infused with Ang II (1000 ηg/kg/min) for 28 days and treated with sildenafil (40 mg/kg/min) or vehicle (Ang II) during the last two weeks. After 4 weeks, the Ang II animals exhibited a high systolic blood pressure (186±3 mmHg vs. 127±3 mmHg for control mice), which was attenuated by sildenafil (163±7 mmHg). The mesenteric vessels from the Ang II animals revealed damage to the endothelial layer, an increase in the cross-section area (1.9-fold) and vascular cell production of peroxynitrite (512±13 a.u.), which was ameliorated in the Ang II-Sil group (1.2-fold and 400±17 a.u.). Analysis of the vascular responsiveness showed an increased contractility response to norepinephrine in Ang II animals (Rmax: 70%), which was abolished by sildenafil through increased nitric oxide (NO) bioavailability and decreased reactive oxygen species (ROS) and vasoconstrictor prostanoids. CONCLUSION: Sildenafil attenuates the morphofunctional deleterious effects of Ang II on resistance vessels. The benefits of sildenafil seem to occur through restoring the balance of ROS/NO/eicosanoids. Therefore, this study opened new avenues for further clinical targeting of the treatment of cardiovascular diseases related to activation of the renin-angiotensin system.

Increased ROS production and DNA damage in monocytes are biomarkers of aging and atherosclerosis

BACKGROUND: New evidence demonstrates that aging and dyslipidemia are closely associated with oxidative stress, DNA damage and apoptosis in some cells and extravascular tissues. However, in monocytes, which are naturally involved in progression and/or resolution of plaque in atherosclerosis, this concurrence has not yet been fully investigated. In this study, we evaluated the influence of aging and hypercholesterolemia on serum pro-inflammatory cytokines, oxidative stress, DNA damage and apoptosis in monocytes from apolipoprotein E-deficient (apoE-/-) mice compared with age-matched wild-type C57BL/6 (WT) mice. Experiments were performed in young (2-months) and in old (18-months) male wild-type (WT) and apoE-/- mice. RESULTS: Besides the expected differences in serum lipid profile and plaque formation, we observed that atherosclerotic mice exhibited a significant increase in monocytosis and in serum levels of pro-inflammatory cytokines compared to WT mice. Moreover, it was observed that the overproduction of ROS, led to an increased DNA fragmentation and, consequently, apoptosis in monocytes from normocholesterolemic old mice, which was aggravated in age-matched atherosclerotic mice. CONCLUSIONS: In this study, we demonstrate that a pro-inflammatory systemic status is associated with an impairment of functionality of monocytes during aging and that these parameters are fundamental extra-arterial contributors to the aggravation of atherosclerosis. The present data open new avenues for the development of future strategies with the purpose of treating atherosclerosis.

Sildenafil (Viagra®) Prevents Cox-1/ TXA2 Pathway-Mediated Vascular Hypercontractility in ApoE-/- Mice.

BACKGROUND/AIMS: The atherosclerotic apolipoprotein E-deficient (apoE-/-) mouse exhibits impaired vasodilation and enhanced vasoconstriction responsiveness. The objectives of this study were: a) to determine the relative contribution of cyclooxygenases (Cox-1 and Cox-2), thromboxane A2 (TXA2) and endothelin-1 (ET-1) to enhancing vascular hyperresponsiveness in this model of atherosclerosis and b) to investigate the beneficial effects of the phosphodiesterase 5 inhibitor sildenafil on this endothelial dysfunction. METHODS: Adult male apoE-/- mice were treated with sildenafil (40 mg/kg/day, for 3 weeks) and compared with non-treated ApoE-/- and wild-type mice. The beneficial effects of sildenafil on vascular contractile response to phenylephrine (PE) in aortic rings were evaluated before and after incubation with Cox-1 (SC-560) or Cox-2 (NS-398) inhibitors or the TP antagonist SQ-29548, and on contractile responsiveness to ET-1. RESULTS: ApoE-/- mice exhibited enhanced vasoconstriction to PE (Rmax ∼35%, p<0.01), which was prevented by treatment with sildenafil. The enhanced PE-induced contractions were abolished by both Cox-1 inhibition and TP antagonist, but were not modified by Cox-2 inhibition. Aortic rings from ApoE-/- mice also exhibited enhanced contractions to ET-1 (Rmax ∼30%, p<0.01), which were attenuated in sildenafil-treated ApoE-/- mice. In addition, we observed augmented levels of vascular proinflammatory cytokines in ApoE-/- mice, which were partially corrected by treatment with sildenafil (IL-6, IL-10/IL-6 ratio and MCP-1). CONCLUSION: The present data show that the Cox-1/TXA2 pathway prevails over the Cox-2 isoform in the mediation of vascular hypercontractility observed in apoE-/-mice. The results also show a beneficial effect of sildenafil on this endothelial dysfunction and on the proinflammatory cytokines in atherosclerotic animals, opening new perspectives for the treatment of other endothelium-related cardiovascular abnormalities.

Chronic administration of the soluble, nonbacterial fraction of kefir attenuates lipid deposition in LDLr-/- mice.

OBJECTIVES: Kefir is obtained by the action of acidic bacteria and yeasts that exist in symbiotic association in kefir grains. Recently, this fermented milk drink has been recommended for the treatment of several clinical conditions, such as inflammatory, gastrointestinal, or cardiovascular-related diseases, or a combination of these diseases. However, its effects on atherosclerosis are not yet clear. The aim of this study was to prove that chronic treatment with a soluble, nonbacterial fraction of kefir could reduce the progression of atherosclerosis in low-density lipoprotein receptor-deficient (LDLr-/-) mice. METHODS: LDLr-/- mice were divided into four groups as follows: RESULTS: The soluble, nonbacterial fraction of kefir reduced lipid deposition (P < 0.05) independent of hypercholesterolemia. Moreover, kefir was capable of diminishing the circulating proinflammatory intereukin (IL)-6 level and the ratio of tumor necrosis factor-α to IL-10 (50% and 42%, P < 0.05, respectively) and augmenting the antiinflammatory IL-10 level by approximately 74% (P < 0.05). CONCLUSIONS: Chronic treatment with a soluble nonbacterial fraction of kefir was able to decrease the lipid deposition in LDLr-/- hypercholesteremic mice, at least in part through modifying the circulating cytokine profile. The beneficial effects of kefir provide new perspectives for its use as an adjuvant in the prevention of atherosclerosis.

Pomegranate peel extract attenuates oxidative stress by decreasing coronary angiotensin-converting enzyme (ACE) activity in hypertensive female rats.

Based on the antioxidant properties of pomegranate, this study was designed to investigate the effects of pomegranate peel extract on damage associated with hypertension and aging in a spontaneously hypertensive rat (SHR) model. The influence of pomegranate consumption was examined on systolic blood pressure (SBP), angiotensin-converting enzyme (ACE) coronary activity, oxidative stress, and vascular morphology. Four- or 28-wk-old SHR model rats were treated for 30 d, with terminal experimental animal age being 8 and 32 wk, respectively, with either pomegranate extract (SHR-PG) or filtered water (SHR). Data showed significant reduction in SBP and coronary ACE activity in both age groups. The levels of superoxide anion, a measure of oxidative stress, were significantly lower in animals in the SHR-PG group compared to SHR alone. Coronary morphology demonstrated total increases in vascular wall areas were in the SHR group, and pomegranate peel extract diminished this effect. Pomegranate peel extract consumption conferred protection against hypertension in the SHR model. This finding was demonstrated by marked reduction in coronary ACE activity, oxidative stress, and vascular remodelling. In addition, treatment was able to reduce SBP in both groups. Evidence indicates that the use of pomegranate peel extract may prove beneficial in alleviating coronary heart disease.

Increased Blood Pressure Variability Prior to Chronic Kidney Disease Exacerbates Renal Dysfunction in Rats.

Increased blood pressure variability (BPV), which can be experimentally induced by sinoaortic denervation (SAD), has emerged as a new marker of the prognosis of cardiovascular and renal outcomes. Considering that increased BPV can lead to organ-damage, the goal of the present study was to evaluate the effects of SAD on renal function in an experimental model of chronic kidney disease (CKD). SAD was performed in male Wistar rats 2 weeks before 5/6 nephrectomy and the animals were evaluated 4 weeks after the induction of CKD. Our data demonstrated that BPV was increased in SAD and CKD animals and that the combination of both conditions (SAD+CKD) exacerbated BPV. The baroreflex sensitivity index was diminished in the SAD and CKD groups; this reduction was more pronounced when SAD and CKD were performed together. 5/6 nephrectomy led to hypertension, which was higher in SAD+CKD animals. Regarding renal function, the combination of SAD and CKD resulted in reduced renal plasma and blood flow, increased renal vascular resistance and augmented uraemia when compared to CKD animals. Glomerular filtration rate and BPV were negatively correlated in SAD, CKD, and SAD+CKD animals. Moreover, SAD+CKD animals presented a higher level of glomerulosclerosis when compared to all other groups. Cardiac and renal hypertrophy, as well as oxidative stress, was also further increased when SAD and CKD were combined. These results show that SAD prior to 5/6 nephrectomy exacerbates renal dysfunction, suggesting that previous augmented BPV should be considered as an important factor to the progression of renal diseases.

Tributyltin chloride induces renal dysfunction by inflammation and oxidative stress in female rats.

Tributyltin chloride (TBT) is an organometallic pollutant that is used as a biocide in antifouling paints. TBT induces several toxic and endocrine-disrupting effects. However, studies evaluating the effects of TBT on renal function are rare. This study demonstrates that TBT exposure is responsible for improper renal function as well as the development of abnormal morphophysiology in mammalian kidneys. Female rats were treated with TBT, and their renal morphophysiology was assessed. Morphophysiological abnormalities such as decreased glomerular filtration rate and increased proteinuria levels were observed in TBT rats. In addition, increases in inflammation, collagen deposition and α-smooth muscle actin (α-SMA) protein expression were observed in TBT kidneys. A disrupted cellular redox balance and apoptosis in kidney tissue were also observed in TBT rats. TBT rats demonstrated reduced serum estrogen levels and estrogen receptor-α (ERα) protein expression in renal cortex. Together, these data provide in vivo evidence that TBT is toxic to normal renal function and that these effects may be associated with renal histopathology complications, such as inflammation and fibrosis.

Effects of Kefir on the Cardiac Autonomic Tones and Baroreflex Sensitivity in Spontaneously Hypertensive Rats.

AIMS: It has been previously shown that the probiotic kefir (a symbiotic matrix containing acid bacteria and yeasts) attenuated the hypertension and the endothelial dysfunction in spontaneously hypertensive rats (SHR). In the present study, the effect of chronic administration of kefir on the cardiac autonomic control of heart rate (HR) and baroreflex sensitivity (BRS) in SHR was evaluated. METHODS: SHR were treated with kefir (0.3 mL/100 g body weight) for 60 days and compared with non-treated SHR and with normotensive Wistar-Kyoto rats. Cardiac autonomic vagal (VT) and sympathetic (ST) tones were estimated through the blockade of the cardiac muscarinic receptors (methylatropine) and the blockade of ß1-adrenoceptor (atenolol). The BRS was evaluated by the tachycardia and bradycardia responses to vasoactive drug-induced decreases and increases in arterial blood pressure (BP), respectively. Additionally, spontaneous BRS was estimated by autoregressive spectral analysis. RESULTS: Kefir-treated SHR exhibited significant attenuation of basal BP, HR, and cardiac hypertrophy compared to non-treated SHR (12, 13, and 21%, respectively). Cardiac VT and ST were significantly altered in the SHR (~40 and ~90 bpm) compared with Wistar rats (~120 and ~30 bpm) and were partially recovered in SHR-kefir (~90 and ~25 bpm). SHR exhibited an impaired bradycardic BRS (~50%) compared with Wistar rats, which was reduced to ~40% in the kefir-treated SHR and abolished by methylatropine in all groups. SHR also exhibited a significant impairment of the tachycardic BRS (~23%) compared with Wistar rats and this difference was reduced to 8% in the SHR-kefir. Under the action of atenolol the residual reflex tachycardia was smaller in SHR than in Wistar rats and kefir attenuated this abnormality. Spectral analysis revealed increased low frequency components of BP (~3.5-fold) and pulse interval (~2-fold) compared with Wistar rats and these differences were reduced by kefir-treatment to ~1.6- and ~1.5-fold, respectively. Spectral analysis also showed an impairment of spontaneous BRS in SHR, but kefir-treatment caused only a tendency to reverse this result. CONCLUSIONS: The novelty of this study is that daily chronic consumption of a low dose of kefir reduced the impairment of the cardiac autonomic control of HR and of the impaired BRS in SHR.

URB597 inhibits oxidative stress induced by alcohol binging in the prefrontal cortex of adolescent rats.

Heavy episodic drinking (binging), which is highly prevalent among teenagers, results in oxidative damage. Because the prefrontal cortex (PFC) is not completely mature in adolescents, this brain region may be more vulnerable to the effects of alcohol during adolescence. As endocannabinoids may protect the immature PFC from the harmful effects of high doses of alcohol, this study investigated the effect of the fatty acid amide hydrolase (FAAH) inhibitor URB597 on oxidative stress induced by acute or chronic binge alcohol intake in adolescent rats. At 40min after intraperitoneal pre-treatment with URB597 (0.3mg/kg) or vehicle (Veh), ethanol (EtOH; 3 or 6g/kg, intragastrically) or distilled water (DW) was administered in 3 consecutive sessions (acute binging) or 3 consecutive sessions over 4 weeks (chronic binging). Oxidative stress in PFC slices in situ was measured by dihydroethidium fluorescence staining. At the higher EtOH dose (6g/kg), pre-treatment with URB597 significantly reduced (p<0.01) the production of superoxide anions in the PFC after acute (42.8% decrease) and chronic binge EtOH consumption (44.9% decrease) compared with pre-treatment with Veh. As URB597 decreases anandamide metabolism, this evidence shows an antioxidant effect of endocannabinoids to suppress acute and chronic binge alcohol intake-induced oxidative stress in the PFC of adolescent rats.

Protective effect of sildenafil on the genotoxicity and cytotoxicity in apolipoprotein E-deficient mice bone marrow cells.

BACKGROUND: The pharmacological inhibitor of phosphodiesterase 5 (PDE5), sildenafil, is a promising candidate for antioxidant therapy that can result in cardiovascular protection. In addition to its known effects on the cardiovascular system, hypercholesterolemia leads to increased oxidative stress and DNA damage in the bone marrow, which is a non-classical target organ of atherosclerosis. In the present study, we evaluate oxidative stress and assess the effect of genomic instability on cell cycle kinetics in atherosclerotic animals and determine if sildenafil reverses these detrimental effects in bone marrow cells. METHODS: Experiments were performed in male wild-type (WT) and apolipoprotein E knockout mice (apoE(-/-)) (9 weeks of age). apoE(-/-) mice were randomly distributed into the following 2 groups: sildenafil-treated (40 mg/kg/day for 3 weeks, n = 8) and vehicle-treated (n = 8), by oral gavage. After treatment, bone marrow cells were isolated to assess the production of superoxide anions and hydrogen peroxide, determine cell cycle kinetics and evaluate the presence of micronucleated cells. RESULTS: Sildenafil treatment reduced the cytoplasmic levels of superoxide anion (~95% decrease, p < 0.05) and decreased hydrogen peroxide (~30% decrease, p < 0.05). Moreover, we observed protective effects on the DNA of bone marrow cells, including normal cell cycling, decreased DNA fragmentation and a diminished frequency of micronucleated cells. CONCLUSION: Our data reveal that the excessive production of ROS in atherosclerotic mice overcome the DNA repair pathways in bone marrow cells. The novelty of the present study is that the administration of sildenafil reduced ROS to baseline levels and, consequently, reverted the DNA damage and its outcomes in bone marrow cells.

Novel Therapeutic Targets for Phosphodiesterase 5 Inhibitors: current state-of-the-art on systemic arterial hypertension and atherosclerosis.

The usefulness of selective inhibitors of phosphodiesterase 5 (PDE5) is well known, first for the treatment of male erectile dysfunction and more recently for pulmonary hypertension. The discovery that PDE5 is present in the systemic artery endothelium and smooth muscle cells led investigators to test the extra sexual effects of sildenafil, the first and most investigated PDE5 inhibitor, in diseases affecting the systemic arteries. Cumulative data from experimental and clinical studies have revealed beneficial effects of sildenafil on systemic arterial hypertension and its target organs, such as the heart, kidneys and vasculature. An important effect of sildenafil is reduction of hypertension and improvement of endothelial function in experimental models of hypertension and hypertensive subjects. Interestingly, in angiotensin-dependent hypertension, its beneficial effects on endothelial and kidney dysfunctions seem to at least in part be caused by its ability to decrease the levels of angiotensin II and increase angiotensin 1-7, in addition to improving nitric oxide bioavailability and diminishing reactive oxygen species. Another remarkable finding on the effects of sildenafil comes from studies in apolipoprotein E knockout mice, a model of atherosclerosis that closely resembles human atherosclerotic disease. In this review, we focus on the promising beneficial effects of sildenafil for treating systemic high blood pressure, especially resistant hypertension, and the endothelial dysfunction that is present in hypertension and atherosclerosis.