In this study we evaluated whether the activation of endogenous angiotensin-converting enzyme (ACE) 2 would improve the cardiovascular autonomic dysfunction of diabetic rats. Ten days after type 1 diabetes induction (Streptozotocin, STZ, 50mg/kg i.v.), the rats were orally treated with 1-[(2-dimethylamino)ethylamino]-4-(hydroxymethyl)-7-[(4-methylphenyl) sulfonyl oxy]-9H-xanthene-9-one (XNT), a newly discovered ACE2 activator (1mg/kg/day), or saline (equivalent volume) during 30 days. Autonomic cardiovascular parameters were evaluated in unanesthetized animals and an isolated heart preparation was used to analyze the cardiac function. Diabetes induced a significant decrease in the baroreflex bradycardia sensibility, as well as in the chemoreflex chronotropic response and parasympathetic tone. The XNT treatment improved these parameters by ~76% (0.82±0.09 vs. 1.44±0.17ΔPI/ΔmmHg), ~85% (−57±9 vs. −105±10 Δbpm) and ~205% (22±2 vs. 66±12 Δbpm), respectively. Also, XNT administration enhanced the bradycardia induced by the chemoreflex activation by ~74% in non-diabetic animals (−98±16 vs. −170±9 Δbpm). No significant changes were observed in the mean arterial pressure, baroreflex tachycardia sensibility, chemoreflex pressor response and sympathetic tone among any of the groups. Furthermore, chronic XNT treatment ameliorated the cardiac function of diabetic animals. However, the coronary vasoconstriction observed in diabetic rats was unchanged by ACE2 activation. These findings indicate that XNT protects against the autonomic and cardiac dysfunction induced by diabetes. Thus, our results evidenced the viability and effectiveness of oral administration of an ACE2 activator for the treatment of the cardiovascular autonomic dysfunction caused by diabetes.

Acute Kidney Injury (AKI) comprises a rapidly developed renal failure and is associated with high mortality rates. The Renin–Angiotensin System (RAS) plays a pivotal role in AKI, as the over-active RAS axis exerts major deleterious effects in disease progression. In this sense, the conversion of Angiotensin II (Ang II) into Angiotensin-(1-7) (Ang-(1-7)) by the Angiotensin-converting enzyme 2 (ACE2) is of utmost importance to prevent worse clinical outcomes. Previous studies reported the beneficial effects of oral diminazene aceturate (DIZE) administration, an ACE2 activator, in renal diseases models. In the present study, we aimed to evaluate the therapeutic effects of DIZE administration in experimental AKI induced by gentamicin (GM) in rats. Our findings showed that treatment with DIZE improved renal function and tissue damage by increasing Ang-(1-7) and ACE2 activity, and reducing TNF-α. These results corroborate with a raising potential of ACE2 activation as a strategy for treating AKI.

Background: Angiotensin Converting Enzyme (ACE) 2 is an important modulator of the Renin Angiotensin System (RAS) and the RAS plays a central role in renovascular hypertension. Very few studies investigated the role of components of the counterregulatory RAS axis (ACE2, Ang-(1-7) and Mas receptor) in renovascular hypertension and the results are controversial. Objective: The aim of this study was to investigate the effects of Diminazene Aceturate (DIZE) administration on renal function and renal inflammation parameters in 2K1C hypertensive rats. Methods: Male Wistar rats were divided into three experimental groups: sham-operated animals, 2K1C+saline and 2K1C+DIZE orally (1 mg/kg/day). At the end of the 30 days of treatment, renal function was analyzed and kidneys from all the groups were collected and processed separately for measurement of N-acetyl-beta-D-glucosaminidase (NAG) and Myeloperoxidase (MPO) activities, cytokines, chemokines and nitric oxide levels. Results: Oral DIZE administration for 4 weeks in hypertensive rats attenuated renal dysfunction and reduced the levels of MPO and NAG, cytokines and chemokines (IL1β, IL-6, TNF-α and MCP-1) and increased urinary nitrate/nitrite levels in 2K1C hypertensive rats. Conclusion: Our findings showed that ACE2 activation may effectively improve renal alterations and inflammation induced by renovascular hypertension.

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It has been demonstrated that carbon nanotubes (CNTs) associated with sodium hyaluronate (HY-CNTs) accelerate bone repair in the tooth sockets of rats. Before clinical application of HY-CNTs, it is important to assess their biocompatibility. Moreover, cardiac toxicity may be caused by the translocation of these particles to the blood stream. The aim of this study was to evaluate possible changes in cardiovascular function in male Wistar rats whose tooth sockets were treated with either CNTs or HY-CNTs (100 μg/mL, 0.1 mL). Blood pressure and heart rate were monitored in conscious rats 7 days after treatment. Cardiac function was evaluated using the Langendorff perfusion technique. The data showed no changes in blood pressure or heart rate in rats treated with either CNTs or HY-CNTs, and no significant changes in cardiac function were found in any of the groups. To confirm these findings, experiments were conducted in rats injected intraperitoneally with a high concentration of either CNTs or HY-CNTs (0.75 mg/kg). The same parameters were analyzed and similar results were observed. The results obtained 7 days following injection indicate that the administration of low concentrations of CNTs or HY-CNTs directly into tooth sockets did not cause any significant change in cardiovascular function in the rats. The present findings support the possibility of using these biocomposites in humans.

No abstract

A promising modification route to improve osseointegration of dental and medical titanium devices is a nanostructured titanium oxide coating layer in the form of self-ordered vertically aligned nanotubes (or nanotubular TiO 2 ). In this work, we report a detailed investigation of nanotubular TiO 2 coating layer on metallic Ti substrate prepared by anodic oxidation. The main goal was to determine an optimized and reproducible route to produce a nanotubular TiO 2 layer with homogenous morphology, narrow distribution and accurate control of the nanotube diameter. The influence of electrolyte temperature, anodizing time and applied voltage were studied, comparing three different electrolytes: 1.5 wt% HF, 0.5 wt% HF, and 0.5 wt% HF+1 mol l −1 H 3 PO 4 . Samples were analyzed by SEM, EDS, FIB, and XPS techniques. The most favorable result was achieved by using 0.5 wt% HF+1 mol l −1 H 3 PO 4 electrolyte, for anodizing time of about 90 min, temperature of 20°C, and anodizing potential from 1 to 25 V. Using these parameters, a uniform self-organized nanotubular TiO 2 layer was prepared with a fine control of the nanotube diameter value over a wide range (10 to 100 nm).

Many activities have been described for propolis, including, antiviral, antibacterial, antifungal, anti-inflammatory, immunoregulatory, antioxidant and wound healing properties. Recently, propolis has been highlighted due to its potential application in the pharmaceutical and cosmetic industries, motivating a better understanding of its antioxidant and anti-inflammatory activities. Propolis and its main polyphenolic compounds presented high antioxidant activity, and effectiveness as broad spectrum UVB and UVA photoprotection sunscreens. Through a qualitative phytochemical screening, the ethanolic red propolis extracts (EEPV) (70% at room temperature and 70% at a hot temperature) presented a positive result for flavonoids and terpenoids. It presented an antioxidant activity for reducing 50% of DPPH of 17 and 12 μg/mL for extraction at room temperature and at a hot temperature, respectively. The UPLC-QTOF-MS/MS analysis allowed the annotation of 40 substances for EEPV-Heated and 42 substances for EEPV-Room Temperature. The IC50 results of the ABTS scavenging activity was 4.7 μg/mL for both extractions, at room temperature and at a hot temperature. Additionally, we also evaluated the cytotoxic profile of propolis extracts against macrophage (RAW 264.7 cells) and keratinocytes (HaCaT cells), which showed non-cytotoxic doses in cell viability assays even after a long period of exposure. In addition, propolis extracts showed antibacterial activity for Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis), demonstrating potential biological activity for the creation of formulations aimed at disease control and prevention.