NMDA Receptor Antagonist Memantine Ameliorates Experimental Autoimmune Encephalomyelitis in Aged Rats

Aging is closely related to the main aspects of multiple sclerosis (MS). The average age of the MS population is increasing and the number of elderly MS patients is expected to increase. In addition to neurons, N-methyl-D-aspartate receptors (NMDARs) are also expressed on non-neuronal cells, such as immune cells. The aim of this study was to investigate the role of NMDARs in experimental autoimmune encephalomyelitis (EAE) in young and aged rats. Memantine, a non-competitive NMDAR antagonist, was administered to young and aged Dark Agouti rats from day 7 after immunization. Antagonizing NMDARs had a more favourable effect on clinical disease, reactivation, and apoptosis of CD4+ T cells in the target organ of aged EAE rats. The expression of the fractalkine receptor CX3CR1 was increased in memantine-treated rats, but to a greater extent in aged rats. Additionally, memantine increased Nrf2 and Nrf2-regulated enzymes' mRNA expression in brain tissue. The concentrations of superoxide anion radicals, malondialdehyde, and advanced oxidation protein products in brain tissue were consistent with previous results. Overall, our results suggest that NMDARs play a more important role in the pathogenesis of EAE in aged than in young rats.

Natural Substances vs. Approved Drugs in the Treatment of Main Cardiovascular Disorders-Is There a Breakthrough?

Cardiovascular diseases (CVDs) are a group of diseases with a very high rate of morbidity and mortality. The clinical presentation of CVDs can vary from asymptomatic to classic symptoms such as chest pain in patients with myocardial infarction. Current therapeutics for CVDs mainly target disease symptoms. The most common CVDs are coronary artery disease, acute myocardial infarction, atrial fibrillation, chronic heart failure, arterial hypertension, and valvular heart disease. In their treatment, conventional therapies and pharmacological therapies are used. However, the use of herbal medicines in the therapy of these diseases has also been reported in the literature, resulting in a need for critical evaluation of advances related to their use. Therefore, we carried out a narrative review of pharmacological and herbal therapeutic effects reported for these diseases. Data for this comprehensive review were obtained from electronic databases such as MedLine, PubMed, Web of Science, Scopus, and Google Scholar. Conventional therapy requires an individual approach to the patients, as when patients do not respond well, this often causes allergic effects or various other unwanted effects. Nowadays, medicinal plants as therapeutics are frequently used in different parts of the world. Preclinical/clinical pharmacology studies have confirmed that some bioactive compounds may have beneficial therapeutic effects in some common CVDs. The natural products analyzed in this review are promising phytochemicals for adjuvant and complementary drug candidates in CVDs pharmacotherapy, and some of them have already been approved by the FDA. There are insufficient clinical studies to compare the effectiveness of natural products compared to approved therapeutics for the treatment of CVDs. Further long-term studies are needed to accelerate the potential of using natural products for these diseases. Despite this undoubted beneficence on CVDs, there are no strong breakthroughs supporting the implementation of natural products in clinical practice. Nevertheless, they are promising agents in the supplementation and co-therapy of CVDs.

Oxidative stress status assessment of rats' brains injury following subacute exposure to K-oximes

Oxidative stress status and morphological injuries in the brain of Wistar rats induced by repeated application of selected acetylcholinesterase reactivators - asoxime, obidoxime, K027, K048, K074, and K075 were evaluated. Each oxime in a dose of 0.1 of LD50/kg im was given 2x/week for 4 weeks. Markers of lipid peroxidation (malondialdehyde, MDA), and protein oxidation (advanced oxidation protein products, AOPP), as well as the activity of antioxidant enzymes (catalase, CAT, superoxide dismutase, SOD, glutathione reductase, GR, and glutathione peroxidase, GPx), were estimated in the brain tissue homogenates on day 35 of the study. Brain alterations were carefully quantified by semiquantitative grading scales - brain damage score (BDS). Oxidative stress parameters, MDA and AOPP were significantly highest in the asoxime-, obidoxime- and K075-treated groups (p < 0.001). The activity of SOD and CAT was significantly elevated in the obidoxime-, K048-, and K075-treated groups (p < 0.001). Besides, GR was markedly decreased in the obidoxime- and K074-treated groups (p < 0.01), while treatment with K048, K074 and K075 induced extremely high elevation in GPx levels (p < 0.001). In the same groups of rats, brain alterations associated with polymorphonuclear cell infiltrate were significantly more severe than those observed in animals receiving only asoxime or K027 (p < 0.001). The presented results confirmed that treatment with different oximes significantly improved the oxidative status and attenuated signs of inflammation in rats' brains. Presented results, together with our previously published data can help to predict likely adverse systemic toxic effects, and target organ systems, which are crucial for establishing risk categories, as well as in dose selection of K-oximes as drug candidates.

Overexpression of MRP1/ABCC1, Survivin and BCRP/ABCC2 Predicts the Resistance of Diffuse Large B-Cell Lymphoma to R-CHOP Treatment

BACKGROUND

Approximately 40% of patients with diffuse large B-cell lymphoma (DLBCL) experience treatment resistance to the first-line R-CHOP regimen. ATP binding cassette (ABC) transporters and survivin might play a role in multidrug resistance (MDR) in various tumors. The aim was to investigate if the coexpression of ABC transporters and survivin was associated with R-CHOP treatment response.

METHODS

The expression of Bcl-2, survivin, P-glycoprotein/ABCB1, MRP1/ABCC1, and BCRP/ABCC2 was analyzed using immunohistochemistry in tumor specimens obtained from patients with DLBCL, and classified according to the treatment response as Remission, Relapsed, and (primary) Refractory groups. All patients received R-CHOP or equivalent treatment.

RESULTS

Bcl-2 was in strong positive correlation with clinical parameters and all biomarkers except P-gp/ABCB1. The overexpression of MRP1/ABCC1, survivin, and BCRP/ABCC2 presented as high immunoreactive scores (IRSs) was detected in the Refractory and Relapsed groups (p < 0.05 vs. Remission), respectively, whereas the IRS of P-gp/ABCB1 was low. Significant correlations were found among either MRP1/ABCC1 and survivin or BCRP/ABCC2 in the Refractory and Relapsed groups, respectively. In multiple linear regression analysis, ECOG status along with MRP1/ABCC1 or survivin and BRCP/ABCG2 was significantly associated with the prediction of the R-CHOP treatment response.

CONCLUSIONS

DLBCL might harbor certain molecular signatures such as MRP1/ABCC1, survivin, and BCRP/ABCC2 overexpression that can predict resistance to R-CHOP.

Resveratrol improved kidney function and structure in malignantly hypertensive rats by restoration of antioxidant capacity and nitric oxide bioavailability

BACKGROUND

The main cause of death among patients with malignant hypertension is a kidney failure. The promising field in essential and malignant hypertension therapy could be centered on the amelioration of oxidative stress using antioxidant molecules like resveratrol. Resveratrol is a potent antioxidative agent naturally occurred in many plants that possess health-promoting properties.

METHODS

In the present study, we investigated the therapeutic potential of resveratrol, a polyphenol with anti-oxidative activity, in N^G-L-Arginine Methyl Ester (L-NAME) treated spontaneously hypertensive rats (SHR) - malignantly hypertensive rats (MHR).

RESULTS

Resveratrol significantly improves oxidative damages by modulation of antioxidant enzymes and suppression of prooxidant factors in the kidney tissue of MHR. Enhanced antioxidant defense in the kidney improves renal function and ameliorates the morphological changes in this target organ. Besides, protective properties of resveratrol are followed by the restoration of the nitrogen oxide (NO) pathway. 4) Conclusion: Antioxidant therapy with resveratrol could represent promising therapeutical approach in hypertension, especially malignant, against kidney damage.

Resveratrol Protects Cardiac Tissue in Experimental Malignant Hypertension Due to Antioxidant, Anti-Inflammatory, and Anti-Apoptotic Properties

Hypertension is one of the most prevalent and powerful contributors of cardiovascular diseases. Malignant hypertension is a relatively rare but extremely severe form of hypertension accompanied with heart, brain, and renal impairment. Resveratrol, a recently described grape-derived, polyphenolic antioxidant molecule, has been proposed as an effective agent in the prevention of cardiovascular diseases. This study was designed to examine chronic resveratrol administration on blood pressure, oxidative stress, and inflammation, with special emphasis on cardiac structure and function in two models of experimental hypertension. The experiments were performed in spontaneously (SHRs) and malignantly hypertensive rats (MHRs). The chronic administration of resveratrol significantly decreased blood pressure in both spontaneously and malignant hypertensive animals. The resveratrol treatment ameliorated morphological changes in the heart tissue. The immunohistochemistry of the heart tissue after resveratrol treatment showed that both TGF-β and Bax were not present in the myocytes of SHRs and were present mainly in the myocytes of MHRs. Resveratrol suppressed lipid peroxidation and significantly improved oxidative status and release of NO. These results suggest that resveratrol prevents hypertrophic and apoptotic consequences induced by high blood pressure with more pronounced effects in malignant hypertension.

Combined Angiotensin II Type-1 Receptor Blockade and Superoxide Anion Scavenging Affect the Post-Ischemic Kidney in Hypertensive Rats

Ischemic acute kidney injury is characterized by renal vasoconstriction, filtration failure, tubular obstruction, tubular backleak and overproduction of angiotensin II and reactive oxygen species. Considering this complexity, the aim of our study was to investigate the effects of angiotensin II type-1 receptor blocker - Losartan and superoxide anion scavenger - Tempol, in a combined treatment on acute kidney injury in postischemic hypertensive rats.

The experiment was performed in anesthetized, adult male spontaneously hypertensive rats. The right kidney was removed and the left renal artery was occluded for 40 minutes. Experimental groups received combined treatment (Losartan + Tempol) or saline in the femoral vein 5 minutes before, during and 175 minutes after clamp removal.

Hemodynamics and biochemical parameters were measured and kidney specimens were collected 24h after reperfusion. Histological examination was performed by optical microscopy.

Combined treatment improves renal haemodynamics parameters which were exacerbated due to acute kidney injury. Acute kidney injury significantly decreased creatinine and urea clearance and increased lipid peroxidation in the plasma. Treatment with Losartan and Tempol induced a significant increase of creatinine and urea clearance. Lipid peroxidation in the plasma decreased and glutathione peroxidase enzyme activity in the erythrocytes increased after Losartan + Tempol treatment. This combined treatment reduced cortico-medullary necrosis and tubular dilatation in the kidney.

Our results indicate that synergism of Losartan and Tempol treatment could have beneficial effects on blood pressure and kidney function, during postischemic acute kidney injury development in experimental hypertension.

Antioxidant and antihypertensive activity of extract from Thymus serpyllum L. in experimental hypertension

The low incidence of cardiovascular disease in Mediterranean countries leads to an increased interest of the scientific community for the Mediterranean diet. Our aim was to evaluate total phenol and flavonoid contents, antioxidant capacity, free radical scavenging activity and potential antihypertensive effect of aqueous extract obtained from Thymus serpyllum L. (wild thyme, TE), an aromatic herb from the Lamiaceae family (highly present in Mediterranean diet), in spontaneously hypertensive rats (SHR) and in normotensive Wistar rats. Total phenol content of TE was 2008.33 ± 10.6 mg/L GAE, and rosmarinic and caffeic acids were predominant phenolic compounds. The ferric reducing/antioxidant power and antioxidant capacity analysis revealed strong antioxidative properties of TE. In vitro nitric oxide-scavenging activity of 1 mg/l TE was 63.43% with the IC50 value of 122.36 μg/ml. Bolus injection of TE (100 mg/kg body weight i.v.) induced significant decrease of systolic and diastolic blood pressure and total peripheral resistance in SHR, without effects on these parameters in normotensive Wistar rats. Cardiac index remained unchanged after TE treatment in all experimental rats. Given dose of TE did not show significant nitric oxide-scavenging activity in vivo. Our results indicate that TE may protect against hypertension in experimental model of essential hypertension.

Comparative effects of L-arginine and vitamin C pretreatment in SHR with induced postischemic acute renal failure

Postischemic acute renal failure is worsened when occurs in a various conditions with impaired nitric oxide (NO) synthesis, such as arterial hypertension. Reoxygenation itself increases ischemic injury through the massive production of oxygen-free radicals. Therefore, we have directed our investigations to effects of both NO donor and antioxidant treatment on course of acute renal failure in experimental hypertension. Experiments were performed in anesthetized, adult male spontaneously hypertensive rats. In ARF groups the right kidney was removed, and rats were subjected to renal ischemia by clamping the left renal artery for 40 min. Experimental group received NO donor L-arginine (2 g/kg b.m.) (LArg group), or oxidant scavenger vitamin C (100 mg/kg b.m.) (Vit C group) during 3 days before the period of ischaemia. All parameters were measured 24 h after reperfusion. The mean arterial pressure was markedly reduced and renal vascular resistance significantly dropped in the ARF+L-Arg group vs. ARF group. Tubular injuries were similar between the ARF+L-Arg and ARF groups. Intensity of tubular necrosis and dilatation was markedly reduced in ARF+Vit C group in comparison to ARF. L-arginine failed to reduce tubular injury, despite its evident improvement of systemic and renal haemodynamic, thus NO seems to act as a double-egged sword, but reduction of tubular injury promotes vitamin C as an effective chemoprotectant against ishemia-reperfusion tubular injury in hypertension.

Effects of angiotensin II type-1 receptor blocker losartan on age-related cardiovascular risk in spontaneously hypertensive rats

Ageing and hypertension are the major risk factors for the development of cardiovascular and renal diseases, and the renin-angiotensin system has been shown responsible for these pathologies. Thus, the aim of this study was to compare the effects of losartan, angiotensin II type-1 receptor blocker, on systolic (SBP), diastolic (DBP), and mean (MBP) blood pressure, pulse pressure (PP) and heart rate as well as regional haemodynamics, cardiac hypertrophy and biochemical parameters in adult (L(9): 9-month-old) and aged (L(18): 18-month-old) spontaneously hypertensive rats (SHRs). Aged match untreated SHRs served as controls (U(9): 9-month-old and U(18): 18-month-old). Aortal blood flow and resistance were significantly improved by losartan treatment in L(9) vs. U(9) (p < 0.05). In aged SHRs, losartan significantly reduced SBP, MBP, PP, right ventricle weight index, and improved age-related impairment of left ventricular weight index (U(18): 4.21 +/- 0.09 mg/g vs. U(9): 3.54 +/- 0.34 mg/g, p < 0.05 and vs. L(18): 3.65 +/- 0.07 mg/g, p < 0.001), carotid, renal, and aortal vascular resistance, and glomerular filtration rate (U(18): 2.75 +/- 0.27 ml/min/kg vs. U(9): 4.84 +/- 0.85 ml/min/kg, p < 0.05 and vs. L(18): 3.65 +/- 0.07 ml/min/kg, p < 0.05). These results demonstrate significantly impaired systemic and regional haemodynamics and left ventricular hypertrophy in old SHRs. Losartan decreased age and hypertension associated cardiovascular risk by decreasing vascular resistance and pressure overload, ventricular hypertrophy, and preserving kidney function.

The effects of iron-containing superoxide dismutases on haemodynamic parameters in spontaneously hypertensive rats

The product of FeSOD activity is hydrogen peroxide (H2O2). Furthermore, FeSOD can modify the chemical versatility of NO into its redox-active forms: nitrosonium cation (NO+) and nitroxyl anion (NO-). All of these low molecular weight species are vasoactive and, in particular, NO- induces calcitonin gene-related peptide (CGRP) synthesis (known to be the most potent relaxation-promoting peptide). In this study the effects of bolus infusions of iron-containing superoxide dismutase (FeSOD) and of superoxide dismutase containing both iron and manganese (FeMnSOD) on the arterial blood pressure (MAP), the arterial blood pressure (CO) and the total vascular resistance (TVR) in spontaneously hypertensive (SH) rats were determined. Bolus infusion of FeSOD induced a biphasic response in the MAP (an initial increase was followed by a significant decrease). At the end of the experiment the MAP returned to its basal value. FeMnSOD (the enzymatically inactive form of FeSOD) had no effect on the MAP in these experiments. Bolus infusions of FeSOD and of FeMnSOD had no effect either on the both the CO or on the TVR in SH rats. Our results indicate that arterial relaxation changes mediated by NO- may be important for regulation of blood pressure in SH rats.