Retroperitoneal adipose tissue denervation improves cardiometabolic and autonomic dysfunction in a high fat diet model.

Sympathetic vasomotor overactivity is a major feature leading to the cardiovascular dysfunction related to obesity. Considering that the retroperitoneal white adipose tissue (rWAT) is an important fat visceral depot and receives intense sympathetic and afferent innervations, the present study aimed to evaluate the effects evoked by bilateral rWAT denervation in obese rats. Male Wistar rats were fed with HFD for 8 consecutive weeks and rWAT denervation was performed at the 6th week. Arterial pressure, splanchnic and renal sympathetic vasomotor nerve activities were assessed and inflammation and the components of the renin -angiotensin system were evaluated in different white adipose tissue depots. HFD animals presented higher serum levels of leptin and glucose, an increase in arterial pressure and splanchnic sympathetic nerve activity; rWAT denervation, normalized these parameters. Pro-inflammatory cytokines levels were significantly increased, as well as RAAS gene expression in WAT of HFD animals; rWAT denervation significantly attenuated these changes. In conclusion, HFD promotes vasomotor sympathetic overactivation and inflammation with repercussions on the cardiovascular system. In conclusion, the neural communication between WAT and the brain is fundamental to trigger sympathetic vasomotor activation and this pathway is a possible new therapeutic target to treat obesity-associated cardiovascular dysfunction.

Afferent innervation of the ischemic kidney contributes to renal dysfunction in renovascular hypertensive rats.

The ablation of renal nerves, by destroying both the sympathetic and afferent fibers, has been shown to be effective in lowering blood pressure in resistant hypertensive patients. However, experimental studies have reported that the removal of sympathetic fibers may lead to side effects, such as the impairment of compensatory cardiorenal responses during a hemodynamic challenge. In the present study, we evaluated the effects of the selective removal of renal afferent fibers on arterial hypertension, renal sympathetic nerve activity, and renal changes in a model of renovascular hypertension. After 4 weeks of clipping the left renal artery, afferent renal denervation (ARD) was performed by exposing the left renal nerve to a 33 mM capsaicin solution for 15 min. After 2 weeks of ARD, we found reduced MAP (~ 18%) and sympathoexcitation to both the ischemic and contralateral kidneys in the hypertensive group. Moreover, a reduction in reactive oxygen species was observed in the ischemic (76%) and contralateral (27%) kidneys in the 2K1C group. In addition, ARD normalized renal function markers and proteinuria and podocin in the contralateral kidney. Taken altogether, we show that the selective removal of afferent fibers is an effective method to reduce MAP and improve renal changes without compromising the function of renal sympathetic fibers in the 2K1C model. Renal afferent nerves may be a new target in neurogenic hypertension and renal dysfunction.

Selective afferent renal denervation mitigates renal and splanchnic sympathetic nerve overactivity and renal function in chronic kidney disease-induced hypertension.

BACKGROUND: Clinical and experimental evidence have shown that renal denervation, by removing both the sympathetic and afferent nerves, improves arterial hypertension and renal function in chronic kidney disease (CKD). Given the key role of renal sympathetic innervation in maintaining sodium and water homeostasis, studies have indicated that the total removal of renal nerves leads to impaired compensatory mechanisms during hemodynamic challenges. METHOD: In the present study, we hypothesized that afferent (or sensory) fibers from the diseased kidney contribute to sympathetic overactivation to the kidney and other target organ, such as the splanchnic region, contributing to hypertension in CKD. We used a method to remove selectively the afferent renal fibers (periaxonal application of 33 mmol/l capsaicin) in a rat model of CKD, the 5/6 nephrectomy. RESULTS: Three weeks after afferent renal denervation (ARD), we found a decrease in mean arterial pressure (∼15%) and normalization in renal and splanchnic sympathetic nerve hyperactivity in the CKD group. Interestingly, intrarenal renin--angiotensin system, as well as renal fibrosis and function and proteinuria were improved after ARD in CKD rats. CONCLUSION: The findings demonstrate that afferent fibers contribute to the maintenance of arterial hypertension and reduced renal function that are likely to be mediated by increased sympathetic nerve activity to the renal territory as well as to other target organs in CKD.

Pattern of sympathetic vasomotor activity in a model of hypertension induced by nitric oxide synthase blockade.

We aimed to investigate the effects of nitric oxide (NO) synthesis inhibition by NO synthase inhibitor N-nitro-L-arginine-methyl ester (L-NAME) treatment on the sympathetic vasomotor nerve activity (SNA) on two sympathetic vasomotor nerves, the renal and splanchnic. NO plasma level and systemic oxidative stress were assessed. Hypertension was induced by L-NAME (20 mg/kg per day, by gavage, for seven consecutive days) in male Wistar rats. At the end of the treatment, blood pressure, heart rate, arterial baroreflex sensitivity, renal SNA (rSNA), and splanchnic SNA (sSNA) were assessed in urethane anesthetized rats. L-NAME-treated rats presented increased blood pressure (152 ± 2 mmHg, n = 17) compared to the control group (101 ± 2 mmHg, n = 15). Both rSNA (147 ± 10, n = 15 vs. 114 ± 5 Spikes/s, n = 9) and sSNA (137 ± 13, n = 14 vs. 74 ± 13 spikes/s, n = 9) were significantly increased in the L-NAME-treated compared to the control group. A differential response on baroreflex sensitivity was found, with a significant reduction for rSNA but not for sSNA arterial baroreceptor sensitivity in L-NAME-treated rats. The adjusted regression model revealed that the reduction of systemic NO levels partially explains the variation in sSNA and blood pressure, but not rSNA. Taken together, our data show that hypertension induced by NO synthase blockade is characterized by increased SNA to the rSNA and sSNA. In addition, we found that the rats that had the greatest reduction in NO levels in plasma by L-NAME were those that developed higher blood pressure levels. The reduction in the NO level partially explains the variations in sSNA but not in rSNA.

Ginkgo biloba Extract Modulates the Retroperitoneal Fat Depot Proteome and Reduces Oxidative Stress in Diet-Induced Obese Rats.

The rapid increase in the number of individuals with obesity, over the past four decades, is triggered by a number of complex interactions among factors. Despite the plethora of treatments available, side effects are commonly observed and, in this context, herbal medicines have been employed as an alternative form of therapy. Ginkgo biloba extract (GbE) has been described as a promising new pharmacological approach to treat obesity. In order to better comprehend the mechanisms involved with this potential effect, the present study evaluated the effects of GbE treatment on diet-induced obese rats, focusing on the proteome and the oxidative stress defense system of visceral adipose tissue. After 14 days treatment, GbE significantly modulated 25 proteins. Retroperitoneal adipose tissue of treated animals exhibited higher amounts of proteins associated with adipogenesis (decorin), carbon metabolism and mitochondrial function (citrate synthase), and a concomitant reduction in adipocyte hypertrophy. In parallel, GbE down-regulated proteins involved in oxidative stress (peroxiredoxin) and the inflammatory response (complement C3, mast cell protease 1, and Ig gamma-2B chain C region). Moreover, also related to oxidative stress defense, GbE stimulated catalase activity, reduced malondialdehyde levels (lipid peroxidation indicator), and increased lactoylglutathione lyase levels. It was concluded that GbE acts as an antioxidant agent, and improved the proteome profile and oxidative stress response in the adipose tissue of diet-induced obese rats.

Dynamic Influence of pH on Metalloproteinase Activity in Human Coronal and Radicular Dentin.

The aim of this study was to evaluate the effect of pH on the activation of matrix metalloproteinases (MMPs) of human coronal (CD) and radicular dentin (RD). CD and RD were pulverized to powder, and proteins were extracted with 1% phosphoric acid. The extracted proteins and the demineralized powder were separately incubated in the following solutions: 4-aminophenylmercuric acetate (control) or a buffer solution at different pHs (2.5, 4.5, 5.0, 6.0, and 7.0). After incubation, proteins were separated by electrophoresis to measure MMP activities by zymography. To assess the solubilized dentin collagen, the demineralized dentin powder was sustained in incubation buffer, and the amount of hydroxyproline (HYP) released was measured. Zymography revealed MMP-2 gelatinolytic activities for CD and RD in all experimental groups. For both substrates, the lowest pH solutions (2.5, 4.5, and 5.0) yielded higher gelatinolytic activity than those obtained by the highest pH solutions (6.0 and 7.0). For HYP analysis, no detectable absorbance values were observed for pHs of 2.5 and 4.5. The amount of HYP was higher for pH 7.0 than those of all other groups (p < 0.05), except for pH 6.0. No statistical differences were found between pHs 6.0 and 5.0 and control (p > 0.05). The MMP-2 enzyme from human CD and RD is dynamically influenced by pH: at low pH, the extracted enzyme activates this latent form, whereas collagen degradation by the matrix-bound enzyme is only observed when pHs are close to neutral.

The antioxidant effects of green tea reduces blood pressure and sympathoexcitation in an experimental model of hypertension.

BACKGROUND: Oxidative stress is a key mediator in the maintenance of sympathoexcitation and hypertension in human and experimental models. Green tea is widely known to be potent antioxidant. OBJECTIVE: We aimed to evaluate the effects of green tea in a model of hypertension. METHODS: Hypertension was induced by the nitric oxide synthase inhibitor [N-nitro-L-arginine-methyl-ester (L-NAME); 20 mg/kg per day, orally, for 2 weeks] in male Wistar rats. After the first week of L-NAME treatment, animals received green tea ad libitum for 1 week. At the end of the treatment period, blood pressure, heart rate, baroreflex sensitivity, renal sympathetic nerve activity, and vascular and systemic oxidative stress were assessed. RESULTS: L-NAME-treated animals exhibited an increase in blood pressure (165 ±â€Š2 mmHg) compared with control rats (103 ±â€Š1 mmHg) and green tea treatment reduced hypertension (119 ±â€Š1 mmHg). Hypertensive animals showed a higher renal sympathetic nerve activity (161 ±â€Š12 spikes/s) than the control group (97 ±â€Š2 spikes/s), and green tea also decreased this parameter in the hypertensive treated group (125 ±â€Š5 spikes/s). Arterial baroreceptor function and vascular and systemic oxidative stress were improved in hypertensive rats after green tea treatment. CONCLUSIONS: Taken together, short-term green tea treatment improved cardiovascular function in a hypertension model characterized by sympathoexcitation, which may be because of its antioxidant properties.

Metabolic remodeling triggered by salivation and diabetes in major salivary glands.

The metabolic profile of major salivary glands was evaluated by 13 C nuclear magnetic resonance isotopomer analysis (13 C NMR-IA) following the infusion of [U-13 C]glucose in order to define the true metabolic character of submandibular (SM) and parotid (PA) glands at rest and during salivary stimulation, and to determine the metabolic remodeling driven by diabetes. In healthy conditions, the SM gland is characterized at rest by a glycolytic metabolic profile and extensive pyruvate cycling. On the contrary, the PA gland, although also dominated by glycolysis, also possesses significant Krebs' cycle activity and does not sustain extensive pyruvate cycling. Under stimulation, both glands increase their glycolytic and Krebs' cycle fluxes, but the metabolic coupling between the two pathways is further compromised to account for the much increased biosynthetic anaplerotic fluxes. In diabetes, the responsiveness of the PA gland to a salivary stimulus is seriously hindered, mostly as a result of the incapacity to burst glycolytic activity and also an inability to improve the Krebs' cycle flux to compensate. The Krebs' cycle activity in the SM gland is also consistently compromised, but the glycolytic flux in this gland is more resilient. This diabetes-induced metabolic remodeling in SM and PA salivary glands illustrates the metabolic need to sustain adequate saliva production, and identifies glycolytic and oxidative pathways as key players in the metabolic dynamism of salivary glands.

Fish oil provides protection against the oxidative stress in pilocarpine model of epilepsy.

Temporal lobe epilepsy (TLE), the most common form of epilepsy is often resistant to pharmacological treatment. Neuronal loss observed in epileptic brain may be result of an overproduction of free radicals (oxidative stress). Oxidative stress is characterized by an imbalance between antioxidant defenses and oxidizing agents (free radicals), which can lead to tissue injury. The n-3 PUFAs are important for the development and maintenance of central nervous system functions. Research by our group has shown that chronic treatment with fish oil, immediately after status epilepticus (SE), exhibits both neuroprotective effects and effects on neuroplasticity. The main purpose of this research was to evaluate if fish oil exhibits a protective effect against oxidative stress. Animals were subjected to TLE model by pilocarpine administration. After 3 h of SE they were randomly divided into the following groups: control animals treated daily with vehicle or with 85 mg/kg of fish oil and animals with epilepsy treated daily with vehicle or with 85 mg/kg of fish oil. After 90 days, superoxide anion production, enzymatic activity of superoxide dismutase (SOD) and catalase (CAT) and protein expression of NAD(P)H oxidase subunits (p47(PHOX) and gp91(PHOX)) were analyzed. Our results showed evidences that reactive oxygen species are increased in animals with epilepsy and that fish oil supplementation could counteract it. Fish oil supplementation promoted protection against oxidative stress by multiple ways, which involved the reduction of activity and expression of NAD(P)H oxidase subunits and increased the activity and expression of antioxidants enzymes, contributing to well-known neuroprotective effect in epilepsy.

Metabolic evaluations of cancer metabolism by NMR-based stable isotope tracer methodologies.

BACKGROUND: Cancer cells are widely recognized for being able to adapt their metabolism towards converting available nutrients into biomass to increase proliferation rates. MATERIALS AND METHODS: We will review a series of nuclear magnetic resonance (NMR)-based stable isotope tracer methodologies for probing cancer metabolism. RESULTS: The monitoring of such adaptations is of the utmost importance to unravel cancer metabolism and tumour growth. Several major metabolic targets have been recognized as promising foci and have been addressed by multiple studies in recent years. In this work are presented strategies to quantify glycolysis, pentose phosphate pathway, Krebs cycle turnover and de novo lipogenesis by NMR isotopomer analysis. CONCLUSIONS: Being able to adequately define the interplay between metabolic pathways allows the monitoring of their prevalence in tissues and such information is critical for an accurate knowledge of the metabolic distinctive nature of tumours towards devising more efficient antitumorigenic strategies. Discussed methodologies are currently available in the literature, but to date, no single review has compiled all their possible uses, particularly in an interdependent perspective.

Antioxidant parameters and lipid peroxidation in salivary glands of streptozotocin-induced diabetic rats.

BACKGROUND: There is evidence suggesting an unbalance between oxidant and antioxidant status associated with diabetes. Considering that salivary function is essential for the maintenance of oral and systemic health, this study was designed to examine the levels of reduced and oxidized glutathione and the activities of the antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione peroxidase, in salivary gland of streptozotocin-induced diabetic rats. METHODS: The content of malondialdehyde was determined in the blood and in the salivary glands. The antioxidant status was investigated in the submandibular and parotid salivary glands. RESULTS: Diabetic rats showed an increase in the content of malonaldehyde in the blood and in the submandibular salivary gland, but not in the parotid gland. Both forms, reduced and oxidized glutathione content present higher values in the diabetic submandibular gland compared with controls. No difference in the activity of superoxide dismutase between the diabetic and control glands was observed in either gland. Catalase showed higher specific activity in the parotid gland of the diabetic rats than control; however, in the submandibular gland, only when expressed as unit per gland was it higher than control. The specific activity of glutathione peroxidase was higher in the diabetic parotid gland than control; however, in the submandibular gland, its activity per gland was lower than controls. CONCLUSION: The streptozotocin-induced diabetes in rats caused different results comparing the submandibular and parotid salivary glands.

Effect of low-power laser irradiation on protein synthesis and ultrastructure of human gingival fibroblasts.

BACKGROUND AND OBJECTIVES: Low-power lasers improve wound healing. Cell proliferation and protein secretion are important steps of this process. The aim of this study was to analyze both protein synthesis and ultrastructural morphology of human gingival fibroblasts irradiated by a low-power laser. STUDY DESIGN/MATERIALS AND METHODS: The cell line FMM1 was grown in nutritional deficit. Laser irradiation was carried out with a gallium-aluminum-arsenate (Ga-Al-As) diode laser (904 nm, 120 mW, energy density of 3 J/cm(2)). The protein synthesis analysis and ultrastructural morphology of control (non-irradiated) and irradiated cultures were obtained. RESULTS: There were changes in the structure of cytoplasm organelles of treated cells. The procollagen was not altered by the laser irradiation; however, there were a significant reduction of the amount of protein in the DMEM conditioned by irradiated cells. CONCLUSIONS: Low-power laser irradiation causes ultrastructural changes in cultured fibroblasts. We suggest that these alterations may lead to disturbances in the collagen metabolism.