Highly potent antioxidant Olea europaea L. leaf extract affects carotid and renal haemodynamics in experimental hypertension

Haemodynamic alterations in carotid and renal arteries are associated with the severity of target organ damage in patients with hypertension. Dietary habits, such as the Mediterranean diet, regulate blood pressure and oxidative stress, thus reduce the mortality rate due to cardiovascular diseases. In this study, our aim was to evaluate the reducing activity, antioxidant capacity and metal chelating ability of standardized Olea europaea L. leaf extract (OLE), and to test its (5, 25, 50 mg/kg) acute in vivo effects, as well as oleuropein’s (OP, 10 mg/kg) on oxidative stress, carotid, renal and systemic haemodynamic parameters (blood pressure, heart rate, cardiac output, peripheral resistance) in spontaneously hypertensive rats (SHR). OLE has a higher antioxidative capacity than BHT, higher reducing ability than vitamin C, and 23 times lower capacity for metal ion chelation than EDTA. All three doses of OLE, and OP, improved oxidative stress in SHR. OLE5 improved carotid and renal haemodynamics, without significant effects on systemic haemodynamics. Two different mechanisms of antihypertensive responses to OLE were observed, OLE25 was most effective in reducing cardiovascular risks by improving systemic and regional (carotid and renal) haemodynamics, peripheral and regional vascular resistance. OLE50 causes the improvement of blood pressure and cardiac performances, but tends to retain elevated vascular resistance, therefore, reducing the inflow of blood into the brain and kidneys of the SHR. The OP did not alter systemic or regional haemodynamics, suggesting others constituents responsible for changes of cardiac function, as well as carotid and renal haemodynamics in response to OLE50

Effects of losartan, tempol, and their combination on renal nitric oxide synthases in the animal model of chronic kidney disease

Down-regulation of nitric oxide synthase (NOS) and NO defi ciency in the kidneys have been implicated in the pathogenesis of chronic kidney disease (CKD). In this study we examined the effects of losartan, tempol, and combined treatment on three NOS isoforms expressions, kidney NO content and NOS correlation with renal function and structure in the early stage of adriamycin (ADR)-induced CKD in spontaneously hypertensive rats (SHR). Rats were divided into control group, and four other groups which were treated with ADR and received vehicle, losartan (L, angiotensin II type 1 receptor blocker), tempol (T, redox-cycling nitroxide) or T + L treatment (by gavage) in a six-week study. Reduction of all NOS isoforms expressions were signifi cantly improved by losartan or tempol, and correlated with proteinuria amelioration. Combined treatment induced down-regulation of constitutive NOS isoforms, whilst inducible NOS was up-regulated and followed by increased nitrite content and a signifi cant decline in the glomerular fi ltration rate. Losartan or tempol prevented ADR-induced neoexpression of vimentin in the glomeruli and tubulointerstital areas, whereas de novo vimentin expression was still observed in the atrophic tubules and in the interstitial fi broblasts and myofi broblasts in combined treatment. It can be concluded that single treatments, contrary to combined, were effective in improving NO bioavailability and slowing down the progression of CKD

Optimization of extraction of stinging nettle leaf phenolic compounds using response surface methodology

A full three level factorial design was implemented for optimization of extraction parameters in order to maximize total phenolic (TP) yield from stinging nettle leaf. Factors considered were percentage of methanol in solvent (X-1 : 50-100% methanol) and extraction time (X-2: 30-90 min), and maceration was used as extraction method. A second-order polynomial model was applied for fitting experimental data and predicting the response, and this mathematical model produced a satisfactory fit (R-2 = 0.993,p LT 0.01). The optimal extraction conditions were 54% aqueous methanol and 38 min extraction time, while maximal theoretical TP yield was 8.9 mg GAE/g DW. Solvent composition significantly affected extraction efficiency causing decrease of TP yield with increase of methanol percentage. On the other hand, extraction time did not influence significantly efficiency of extraction. Using LC/MS and HPLC analysis we detected and quantified three most abundant phenolic compounds: 2-O-caffeoyl malic acid, chlorogenic acid, and rutin. Comparison between maceration and ultrasound-assisted extraction (UAE) obtained extracts based on TP content as well as antiradical activity and HPLC results, showed that UAE have a better extraction capability affecting yield and time of extraction. Of all tested extracts, 54% aqueous methanolic extracts obtained with UAE and 38 min extraction time had the highest TP content

Immunohistochemical Pattern of Histone H2A Variant Expression in an Experimental Model of Ischemia–Reperfusion-Induced Acute Kidney Injury

Ischemia–reperfusion injury (IRI) is a frequent cause of AKI, resulting in vasoconstriction, cellular dysfunction, inflammation and the induction of oxidative stress. DNA damage, including physical DNA strand breaks, is also a potential consequence of renal IRI. The histone H2A variants, primary H2AX and H2AZ participate in DNA damage response pathways to promote genome stability. The aim of this study was to evaluate the immunohistochemical pattern of histone H2A variants’ (H2AX, γH2AX(S139), H2AXY142ph and H2AZ) expression in an experimental model of ischemia–reperfusion-induced acute kidney injury in spontaneously hypertensive rats. Comparing the immunohistochemical nuclear expression of γH2AX(S139) and H2AXY142ph in AKI, we observed that there is an inverse ratio of these two histone H2AX variants. If we follow different regions from the subcapsular structures to the medulla, there is an increasing extent gradient in the nuclear expression of H2AXY142ph, accompanied by a decreasing nuclear expression of γH2AX. In addition, we observed that different structures dominated when γH2AX and H2AXY142ph expression levels were compared. γH2AX was expressed only in the proximal tubule, with the exception of when they were dilated. In the medulla, H2AXY142ph is predominantly expressed in the loop of Henle and the collecting ducts. Our results show moderate sporadic nuclear H2AZ expression mainly in the cells of the distal tubules and the collecting ducts that were surrounded by dilated tubules with PAS (periodic acid–Schiff stain)-positive casts. These findings may indicate the degree of DNA damage, followed by postischemic AKI, with potential clinical and prognostic implications regarding this condition

Glomerular nestin expression in experimental groups.

<p>(<b>A</b>) Negative control (×200). (<b>B</b>) SHC group: Nestin was observed focally in some of glomeruli, whereby expression was usually limited on single podocyte per glomerulus. (<b>C</b>) SHADR group: Diffuse glomerular nestin expression was detected involving almost all podocytes within glomerulus. After losartan and tempol treatment, either single or in combination, kidneys restored nestin expression similar to controls (SHC group). Thus, SHADR+L group (<b>D</b>), SHADR+T group (<b>E</b>) and SHADR+T+L group (<b>F</b>) exhibited similar glomerular nestin immunomorphological profile as observed in control animals. However, in addition to rare expression in podocytes, nestin was also detected in some interstitial cells, mainly within periglomerular area, as it is shown in images (E) and (F). Arrows indicate nestin expressing cells (podocytes and interstitiual cells). Magnification for images B-F ×400.</p

Antioxidant enzymes activities in kidney among the experimental groups.

<p>SOD—superoxide dismutase, CAT—catalase, and GSH-Px—glutathione peroxidase. *<i>p<0</i>.<i>05</i>, **<i>p<0</i>.<i>01</i>, ***<i>p<0</i>.<i>001</i> vs. SHC; ^#<i>p<0</i>.<i>05</i>, ^###<i>p<0</i>.<i>001</i> vs. SHADR; ^$<i>p<0</i>.<i>05</i>, ^$ $<i>p<0</i>.<i>01</i>, ^$ $$<i>p<0</i>.<i>001</i> vs. SHADR+L; ^&&<i>p<0</i>.<i>01</i> vs. SHADR+T; n = 8 animals per group. Data represent mean ± SEM. SHC—control group, SHADR–SHR treated with adriamycin, L—losartan, T—tempol.</p

Kidney MMP-1, Nox4 and Nox2 protein levels in experimental groups.

<p><i>*p<0</i>.<i>05</i>, <i>**p<0</i>.<i>01</i>, <i>***p<0</i>.<i>001</i> vs. SHC; <i>###p<0</i>.<i>001</i> vs. SHADR; <i>$$ $p<0</i>.<i>001</i> vs. SHADR+L; k- kidney; Data represent mean ± SEM; n = 6 rats in each group; SHC—control group, SHADR–SHR treated with adriamycin, L—losartan, T–tempol.</p

The correlation among Up/cr, Up, Pcr, pTBARS, PCOs, and morphological changes of the kidney in all experimental groups (n = 23).

<p>The correlation among Up/cr, Up, Pcr, pTBARS, PCOs, and morphological changes of the kidney in all experimental groups (n = 23).</p

Systolic arterial pressure (SAP), urine protein-to-creatinine ratio (Up/cr), urine protein (Up), and plasma creatinine (Pcr) in experimental groups.

<p><i>*p<0</i>.<i>05</i>, <i>**p<0</i>.<i>01</i>, <i>***p<0</i>.<i>001</i> vs. SHC; <i>#p<0</i>.<i>05</i>, <i>###p<0</i>.<i>001</i> vs. SHADR; <i>$p<0</i>.<i>05</i>, <i>$ $p<0</i>.<i>01</i>, <i>$ $$p<0</i>.<i>001</i> vs. SHADR+L; n = 6–7 animals per group. Data represent mean ± SEM. SHC—control group, SHADR–SHR treated with adriamycin, L—losartan, T–tempol.</p