Tadalafil and bergapten mitigate streptozotocin-induced sporadic Alzheimer's disease in mice via modulating neuroinflammation, PI3K/Akt, Wnt/ß-catenin, AMPK/mTOR signaling pathways.

Sporadic Alzheimer's disease (SAD) is a slowly progressive neurodegenerative disorder. This study aimed to investigate neuroprotective potential of tadalafil (TAD) and bergapten (BG) in SAD-induced cognitive impairment in mice. SAD was induced by single injection of streptozotocin (STZ; 3 mg/kg, ICV). STZ resulted in AD-like pathologies including Aß deposition, tau aggregation, impaired insulin and Wnt/ß-catenin signaling, as well as autophagic dysfunction and neuroinflammation. Administration of TAD or BG at doses of 20 and 25 mg/kg, respectively, for 21 consecutive days attenuated STZ-induced hippocampal insult, preserved neuronal integrity, and improved cognitive function in the Morris water maze and object recognition tests paralleled by reduction in Aß expression by 79 and 89% and tau hyperphosphorylation by 60 and 61%, respectively. TAD and BG also enhanced protein expression of pAkt, pGSK-3ß, beclin-1 and methylated protein phosphatase 2A (PP2A) and gene expression of cyclin D1, while raised BDNF immunoreactivity. Furthermore, TAD and BG boosted hippocampal levels of cGMP, PKG, Wnt3a, and AMPK and reduced expression of ß-catenin and mTOR by 74% and 51%, respectively. TAD and BG also halted neuroinflammation by reducing IL-23 and IL-27 levels, as well as protein expression of NF-κB by 62% & 61%, respectively. In conclusion, this study offers novel insights on the neuroprotective effects of TAD or BG in the management of SAD as evidenced by improved cognitive function and histological architecture. This could be attributed to modulation of the crosstalk among PI3K/Akt/GSK-3ß, PP2A, mTOR/autophagy, cGMP/PKG, and Wnt/ß-catenin signaling cascades and mitigation of neuroinflammation.

Protective effect of sitagliptin and whole-body γ-irradiation in diabetes-induced cardiac injury.

Diabetes mellitus is associated with an increased risk of cardiac complications; this study aimed to investigate effect of sitagliptin (SITA) alone or combined with γ-irradiation on diabetes-associated cardiac injury. Rats were treated with SITA (100 mg/kg per day; p.o.) for 2 weeks followed by a single dose of whole-body γ-irradiation (3 Gy). Solitary administration of SITA or combined treatment with γ-irradiation succeeded to ameliorate the increase in serum levels of glucose, total cholesterol, triglycerides, creatine kinase-MB, and malondialdehyde, coupled by increased insulin and reduced glutathione levels. Their cardioprotective potential was confirmed through attenuating the apoptotic signaling by mitigating Bcl-2-associated X protein, caspase-3, and apoptosis-inducing factor expression, while augmenting the anti-apoptotic factors, B cell lymphoma-2 (Bcl-2), and heat shock protein 70 (HSP-70) in left ventricular tissue homogenates. These findings were supported histopathologically. In conclusion, treatment with SITA alone or combined with γ-irradiation may prove beneficial in diabetes-accompanied cardiac insult. This could be due to the crosstalk between the antioxidant, anti-apoptotic, and restoration of body's defense capacities.

MiR-200a inversely correlates with Hedgehog and TGF-ß canonical/non-canonical trajectories to orchestrate the anti-fibrotic effect of Tadalafil in a bleomycin-induced pulmonary fibrosis model.

Few reports have documented the ability of phosphodiesterase-5 inhibitors (PDE-5-Is) to ameliorate idiopathic pulmonary fibrosis (IPF) mainly by their anti-inflammatory/antioxidant capacities, without unveiling the possible molecular mechanisms involved. Because of the recent role of miR-200 family and Sonic Hedgehog (SHH) trajectory in IPF, we have studied their impact on the anti-fibrotic potential of tadalafil against bleomycin-induced pulmonary fibrosis. Animals were allocated into normal-control, bleomycin-fibrotic control, and bleomycin post-treated with tadalafil or dexamethasone, as the reference drug. On the molecular level, tadalafil has reverted the bleomycin effect on all the assessed parameters. Tadalafil upregulated the gene expression of miR-200a, but decreased the smoothened (SMO) and the transcription factors glioma-associated oncogene homolog (Gli-1, Gli-2), members of SHH pathway. Additionally, tadalafil ebbed transforming growth factor (TGF)-ß, its canonical (SMAD-3/alpha smooth muscle actin [α-SMA] and Snail), and non-canonical (p-Akt/p-Forkhead box O3 (FOXO3) a) pathways. Besides, a strong negative correlation between miR-200a and the analyzed pathways was proved. The effect of tadalafil was further confirmed by the improved lung structure and the reduced Ashcroft score/collagen deposition. The results were comparable to that of dexamethasone. In conclusion, our study has highlighted the involvement of miR-200a in the anti-fibrotic effect of tadalafil with the inhibition of SHH hub and the pro-fibrotic pathways (TGF-ß/ SMAD-3/α-SMA, Snail and p-AKT/p-FOXO3a). Potential anti-fibrotic effect of tadalafil. Modulation of miR200a/SHH/canonical and non-canonical TGF-ß trajectories. → : stimulatory effect; ┴: inhibitory effect.

Novel insights into gut health: Cilostazol strengthens gut integrity by adjusting TLR-2/NF-κB/IL-23 and CD44/AKT/GSK-3ß/cyclin-D1 trajectories in methotrexate-induced mucositis model.

Methotrexate (MTX)-induced gastrointestinal mucositis is a common adverse effect characterized by redox imbalance and overproduction of inflammatory mediators that perturb intestinal integrity. Currently, there is no definitive treatment for this condition and its prevention is still far beyond comprehension. Because of its pleiotropic pharmacological actions, we aimed to explore the potential mechanisms through which cilostazol (CILO) can protect against MTX-induced intestinal mucositis. Wistar rats were allocated into 4 groups, control, CILO (100 mg/kg, p.o for 14 days), MTX (7.5 mg/kg for 4 successive days), and CILO + MTX. The improving effect of CILO on the morphological structure was confirmed by an upturn in the histopathological and transition electron microscope examinations evidenced by the increased jejunal villus height/width and the crypt depth besides the maintenance of tight junctions. These findings were verified biochemically; on the molecular level, CILO reduced the MTX-induced lipid peroxidation, cleaved caspase-3, p53, and the inflammatory parameters (TLR-2, NF-κB, IL-23, TNF-α, IL-1ß), while increasing the anti-inflammatory marker IL-10 and the antioxidant enzyme SOD. Moreover, CILO decreased the injurious axis AKT/GSK-3ß/cyclin-D1, and CD44+, but increased the immunoexpression of the cell proliferating marker PCNA. CILO also upheld the intestinal barrier by enhancing the tight junction molecules (ZO-1, claudin-4) and the E-cadherin/ß-catenin complex while abating the mesenchymal marker vimentin. In conclusion, CILO protected gut integrity by reducing the epithelial-mesenchymal transition process, the MTX-induced oxidative, apoptotic, and inflammatory mediators, and turning off the CD44/AKT/GSK-3ß/cyclin D1 trajectory and intensifying the expression of PCNA.

Vitamin D Combined with Pioglitazone Mitigates Type-2 Diabetes-induced Hepatic Injury Through Targeting Inflammation, Apoptosis, and Oxidative Stress.

Inflammation is a major pathophysiological factor in development of type-2 diabetes mellitus (T2DM). Vitamin D (VITD) plays an imperative role in modulation of several inflammatory responses. The current study aimed to investigate the possible beneficial effects of coadministration of VITD with pioglitazone (PIO), a PPAR-γ agonist, in fructose/streptozotocin (F/STZ) T2DM model in male Wistar rats. T2DM was induced by maintaining rats on 10% (w/v) fructose in drinking water for 9 weeks with an intraperitoneal injection of sub-diabetogenic dose of STZ (35 mg/kg) by the end of the fourth week. One week after STZ injection, PIO (10 mg/kg/day) alone or with VITD (500 IU/kg/day) was administered orally to diabetic rats till the end of the experiment. Blood samples were collected, livers were homogenized to determine biochemical parameters, and samples of livers were fixed in 10% formalin in saline for histological examination. Administration of PIO alone improved diabetes-induced inflammatory and oxidative states besides controlling hyperglycemia and decreasing apoptosis. Coadministration of VIT D with PIO promoted additional improvement in glycemic and lipid profiles, provided further control on diabetic-induced hepatic inflammation evident by downregulating TLR2, TLR4, and IKK-ß while upregulating IκB-α expression and reducing inflammatory cytokines namely; NF-κB, TNF-α, IL-6, and IL-1ß, decreasing apoptosis and oxidative stress by hampering caspase-3 and MDA contents, respectively, and improved liver histology than PIO alone. These beneficial effects of VIT D may expand its use by diabetics combined with antidiabetic drugs due to its anti-inflammatory, antioxidant, and antiapoptotic properties.

Artificial intelligence-assisted development of in situ forming nanoparticles for arthritis therapy via intra-articular delivery.

Intra-articular (IA) injection is grasping much interest due to the poor drug bioavailability at the targeted site of action which minimizes the effect of the orally administered moiety. Based on the integral role of non-steroidal anti-inflammatory drugs (NSAIDs) in the treatment of Rheumatoid Arthritis (RA), much effort is exerted to develop novel localized drug delivery systems to increase their bioavailability and minimize their side effects. Artificial intelligence (AI) is acquiring an increasing role in the design of experiments being an effective tool for saving both time and resources. Hence, the aim of this work was to develop, characterize and optimize targeted in-situ forming nano particles (ISNs) for IA delivery of piroxicam using Design® Expert as an AI-based application where a 33 full factorial experimental design was adopted. Morphological investigation, injectability, rheological studies, Fourier Transform Infrared Radiation (FTIR) as well as biological, histopathological, and biochemical examinations were performed to evaluate the optimized-ISNs. The optimized formulation, exhibiting a nano-sized particle size with a dense core, showed significant improvement in the histopathological findings compared to both the oral solution and the placebo. Additionally, the once-a-week IA administration of the optimized-ISNs proved a significant reduction in the protein expression of both STAT-3 and RANKL and the levels of anti-CCP and MCP-1 by almost 54 and 73%, respectively, coupled with a marked decline in the content of IL-17, MMP-3, NF-κB and TNF-α as compared to the positive control. In conclusion, the use of ISNs for intra-articular injection has demonstrated their effectiveness in piroxicam delivery for RA treatment.

Repositioning of Ticagrelor: Renoprotection mediated by modulating renin-angiotensin system, inflammation, autophagy and galectin-3.

Aside from being an antiplatelet, ample studies revealed the anti-ischemic cardioprotective effect of Ticagrelor (Tica) mediated via different mechanisms; however, its protective potential against renal ischemia reperfusion (I/R) has been rarely investigated, which is the aim of the current study. Animals were divided into sham, I/R (45 min/24 h) and I/R pretreated with Tica (30 mg/kg) for one week, after a pilot study using 30 and 150 mg/kg of Tica. The pre-administration of Tica (30 mg/kg) guarded against the harmful impact of I/R insult and improved renal histological structure and function validated by reducing cystatin-C, neutrophil gelatinase-associated lipocalin, interleukin-18 and the classical markers, blood urea nitrogen and creatinine. On the molecular level, Tica signified its anti-inflammatory capacity by inhibiting nuclear factor κB and tumor necrosis factor-α, while it enhanced the autophagy process evidenced by increasing the protein expression of Beclin-1 and microtubule-associated protein light chain 3 II and abating the lysosomal marker cathepsin-D. Besides, Tica augmented cell survival by inhibiting galectin-3 and caspase-3 activity. Additionally, Tica modulated the renin-angiotensin system (RAS), where it decreased angiotensin II and downregulated the gene expression of prorenin and endothelin-1A receptors, but increased the activity of angiotensin converting enzyme-2 and the renal content of angiotensin 1-7. Our study is the first to highlight the renal anti-ischemic potential of Tica via enhancing autophagy, modulating the RAS, and decreasing both inflammation and cell demise.

Sodium hydrogen sulfide upregulates cystathionine ß-synthase and protects striatum against 3-nitropropionic acid-induced neurotoxicity in rats.

OBJECTIVES: Hydrogen sulfide (H2S) is a neuromodulator that plays a protective role in multiple neurodegenerative diseases including Alzheimer's (AD) and Parkinson's (PD). However, the precise mechanisms underlying its effects against Huntington's disease (HD) are still questioned.This study aimed to examine the neuroprotective effects of sodium hydrogen sulfide (NaHS; H2S donor) against 3-nitropropionic acid (3NP)-induced HD like pathology in rats. Methods: Male Wistar rats were randomly allocated into four groups; (1) normal control receiving saline; (2) NaHS control receiving (0.5 mg/kg/day, i.p.) for 14 days; (3,4) receiving 3NP (10 mg/kg/day, i.p.) for 14 days, with NaHS 30 min later in group 4. KEY FINDINGS: NaHS improved cognitive and locomotor deficits induced by 3NP as confirmed by the striatal histopathological findings. These former events were biochemically supported by the increment in cystathionine ß-synthase (CBS) gene expression, reduction of glutamate (Glu), dopamine (DA), malondialdehyde (MDA), tumour necrosis factor-alpha (TNF-α), cytochrome-c, cleaved caspase-3 and pc-FOS indicating antioxidant, anti-inflammatory as well as anti-apoptotic effects. Furthermore, NaHS pretreatment improved cholinergic dysfunction and increased brain-derived neurotropic factor (BDNF) and nuclear factor erythroid-2-related factor 2 (Nrf2). CONCLUSIONS: These findings suggest that appropriate protection with H2S donors might represent a novel approach to slow down HD-like symptoms.

Formulation and optimization of sildenafil citrate-loaded PLGA large porous microparticles using spray freeze-drying technique: A factorial design and in-vivo pharmacokinetic study.

The oral administration of sildenafil citrate (SC) for the treatment of pulmonary arterial hypertension is associated with several drawbacks. The study aimed to design and formulate SC-loaded inhalable poly (lactic-co-glycolic acid) [PLGA] large porous microparticles (LPMs) for pulmonary delivery. A factorial design was used to study the effect of the composition of LPMs on physicochemical properties. The study also evaluated the effect of glucose and L-leucine concentration on the formulation. The developed LPMs demonstrated an acceptable yield% (≤48%), large geometric particle size (>5µm) with a spherical and porous surface, and sustained drug release (up to 48 h). Increasing the concentration of poly(ethyleneimine) from 0.5% to 1% in SC-loaded LPMs led to an increase in entrapment efficiency from ~3.02% to ~94.48%. The optimum LPMs showed adequate aerodynamic properties with a 97.68 ± 1.07% recovery, 25.33 ± 3.32% fine particle fraction, and low cytotoxicity. Intratracheal administration of LPMs demonstrated significantly higher lung deposition, systemic bioavailability, and longer retention time (p < 0.05) compared to orally administered Viagra® tablets. The study concluded that SC-loaded LPMs could provide better therapeutic efficacy, reduced dosing frequency, and enhanced patient compliance.

The Effect of Liver and Kidney Disease on the Pharmacokinetics of Clozapine and Sildenafil: A Physiologically Based Pharmacokinetic Modeling.

BACKGROUND AND OBJECTIVES: Physiologically based pharmacokinetic (PBPK) modeling permits clinical scientists to reduce practical constraints for clinical trials on patients with special diseases. In this study, simulations were carried out to validate the pharmacokinetic parameters of clozapine and sildenafil using Simcyp® simulator in young male adults and compare the effect of renal or hepatic impairment on the pharmacokinetic parameters of clozapine and sildenafil. Also, the effect of age on pharmacokinetic parameters of both drugs was investigated in healthy population and in patients with renal and hepatic impairment. METHODS: A full PBPK model was built in the simulator for clozapine and sildenafil based on physicochemical properties and observed clinical results. The model used was Advanced, Dissolution, Absorption and Metabolism (ADAM) for both drugs. RESULTS: The PBPK model adequately predicted the pharmacokinetic parameters of clozapine and sildenafil for the healthy adult population. In the simulation results, the bioavailability of both drugs was remarkably raised in both renal and hepatic impairment in young and elderly populations. CONCLUSION: PBPK modeling could be helpful in the investigation and comparison of the pharmacokinetics in populations with specific disease conditions.

Phytochemical profile and protective effect of Ocimum basilicum aqueous extract in doxorubicin/irradiation-induced testicular injury.

OBJECTIVES: Combined chemotherapy and radiotherapy usually associated with various comorbidities especially on rapidly proliferating cells as testis. This study aimed to characterize main constituents of Ocimum basilicum L. (OB) aqueous extract and examine its protective effect on doxorubicin/irradiation (DOXO/IR)-induced testicular injury in rats. METHODS: Spectrophotometric analysis showed considerable amount of polyphenolic (146.31 µg/mg) and flavonoid contents (28.63 µg/mg); UPLC-ESI-MS/MS analysis revealed that the major flavonoid was apigenin-O-glucoside (7.53%) followed by luteolin (5.94%), while rosmarinic acid was the major polyphenolic (15.76%) followed by caftaric acid (9.39%); rutin and querctin were also present and were quantified using high-performance liquid chromatography. Administration of OB extract (200 mg/kg per day; p.o.) to DOXO/IR rats resulted in marked improvement of associated testicular damage. KEY FINDINGS: Ocimum basilicum L. significantly decreased testicular levels of nuclear factor-kappa B and B-cell lymphoma-2 (Bcl2)-associated protein X, along with caspase-3 immunohistochemical staining. In addition, OB elevated testicular total antioxidant capacity, nuclear erythroid-related factor-2, Bcl2 and testosterone contents and Ki-67 immunohistochemical staining. Such changes were also accompanied by restoration of testicular architecture. CONCLUSIONS: The study highlights the protective role of OB aqueous extract in hampering most of the harmful chemotherapy/radiotherapy-induced outcomes via its antioxidant, antiapoptotic and cell regeneration abilities. Such findings may offer an incentive in expanding its use during chemotherapy and radiotherapy.

Venlafaxine alleviates complete Freund's adjuvant-induced arthritis in rats: Modulation of STAT-3/IL-17/RANKL axis.

AIMS: Rheumatoid arthritis is usually accompanied by various comorbidities especially on the psychological side such as depression. This study aimed at revealing the potential curative effects of venlafaxine (VFX), a serotonin/norepinephrine reuptake inhibitor (SNRI), on experimentally-induced arthritis in rats. METHODS: Arthritis was induced by injecting complete Freund's adjuvant (CFA, 0.1 ml, s.c.). One day thereafter, VFX (50 mg/kg, p.o.) was given for 21 days. Methotrexate was used as a standard disease modifying anti-rheumatic drug. KEY FINDINGS: CFA injection caused prominent arthritis evident by the increase in the hind paw and ankle diameter accompanied by elevating tumor necrosis factor-alpha, interleukin-6, interleukin-17 and matrix metalloproteinase-3 levels, effects that were diminished by VFX. Moreover, VFX down regulated gene expressions of receptor activator of nuclear factor kappa-B (NF-кB) ligand and signal transducer and activator of transcription-3 beside hampering immunohistochemical expression of vascular endothelial growth factor and NF-кB. This SNRI also improved the oxidant status of the hind limb as compared to the arthritic group. Nonetheless, MTX was better in amendment of arthritis authenticated by its effect on some inflammatory and oxidative stress biomarkers. SIGNIFICANCE: This study provides a novel therapeutic use of VFX as a considerable anti-arthritic drug and offers an incentive to expand its use in RA.

Design and evaluation of novel inhalable sildenafil citrate spray-dried microparticles for pulmonary arterial hypertension.

Pulmonary delivery of vasodilators is a promising alternative for the intravenous and oral treatment of pulmonary arterial hypertension (PAH). The aim of this study was to design and evaluate hydrogel microparticles as a carrier for sustained pulmonary delivery of sildenafil citrate. Spray dried hydrogel microparticles containing biodegradable sodium carboxymethyl cellulose, sodium alginate, and sodium hyaluronate polymers at variable concentrations were prepared. A design of experiment using the "Extreme Vertices Mixture" design was executed. The design was used to study the influence of polymer concentration and their interactions on the physicochemical properties of the formulations in terms of particle size, particle size distribution, product yield, entrapment efficiency, and in-vitro drug release. Selected formulations were also evaluated for swelling, biodegradation, moisture content, in-vitro aerodynamic performance, and cytotoxicity. In addition, a lung deposition and pharmacokinetic study was conducted in rats to study drug accumulation in lungs and blood after intratracheal administration of the spray dried inhalable hydrogel microparticles in comparison to orally administered Viagra®. The results demonstrated that formulated microparticles had a mean geometric particle size between 2 and 5 µm, entrapment efficiency of >80%, and yield ranging between 47 and 66% w/w. The in-vitro drug release profiles showed a sustained drug release of sildenafil citrate for over 24 h. The statistical design showed a significant influence of the microparticulate composition on the physicochemical properties. Furthermore, selected formulations were evaluated for their aerodynamic properties. The aerodynamic properties included fine particle fraction ranging between 24 and 30%, dose recovery percent of 68-8 5%, and average mass median aerodynamic diameter of 4.6-4.8 µm. The in-vivo pharmacokinetic study showed that inhaled spray dried hydrogel microparticles (M6) formulation had significantly higher lung/blood Cmax, AUC, extended half-life, and mean residence time in comparison to orally administered sildenafil citrate of the same dose. In conclusion, the formulated drug-loaded spray dried hydrogel microparticles showed promising in-vitro and in-vivo results for the pulmonary delivery of sildenafil citrate. The spray dried hydrogel microparticles formulation can be considered as a potential alternative of oral sildenafil citrate for treatment of PAH.

Novel Anti-arthritic Mechanisms of Polydatin in Complete Freund's Adjuvant-Induced Arthritis in Rats: Involvement of IL-6, STAT-3, IL-17, and NF-кB.

Articular manifestations are the main hall mark for rheumatoid arthritis; inflammation and oxidative stress are involved in its pathogenesis. This study was designed to figure out the possible therapeutic potential of polydatin on experimentally induced arthritis in rats. Polydatin (POLY) was administered (200 mg/kg, p.o.) for 21 days to complete Freund's adjuvant (CFA; 0.1 ml, s.c.)-induced arthritic rats. Meanwhile, methotrexate (MTX; 0.75 mg/kg, i.p.) was given as a reference standard disease-modifying anti-rheumatic drug (DMARD). Both POLY and MTX significantly attenuated articular damage associated with CFA-induced arthritis. This was manifested by reducing levels of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), interleukin-17 (IL-17), and matrix metalloproteinase-3 (MMP-3), paralleled with marked decrease in hind paw and ankle diameters. Moreover, POLY and MTX downregulated gene expressions of receptor activator of nuclear factor kappa-B ligand (RANKL) as well as signal transducer and activator of transcription-3 (STAT3) besides hampering immunohistochemical staining of vascular endothelial growth factor (VEGF) and nuclear factor kappa-B (NF-κB). Furthermore, substantial decline in myeloperoxidase (MPO) activity and malondialdehyde (MDA) level associated with significant rise in reduced glutathione content (GSH) was observed. These findings provide an innovative therapeutic approach of POLY as a natural anti-arthritic drug through modulating IL-6/STAT-3/IL-17/NF-кB cascade. Graphical Abstract ᅟ.

Ginkgo biloba extract (EGb 761) normalizes hypertension in 2K, 1C hypertensive rats: role of antioxidant mechanisms, ACE inhibiting activity and improvement of endothelial dysfunction.

The 2 kidney, 1-clip (2K, 1C) model of hypertension was used to investigate the potential antihypertensive effect of a standardized leaf extract of Ginkgo biloba (EGb 761). Clipping of the renal artery resulted in gradual elevation of the systolic blood pressure (SBP) reaching a plateau after 4 weeks of surgery. Treatment of hypertensive rats with EGb 761 (60, 90, 180 mg/kg/day orally) was therefore started 4 weeks after surgery and continued for 3 weeks. This led to a dose-dependent reduction in SBP with no significant change in heart rate. Control hypertensive rats showed a significant elevation of total protein thiols (Pr-SHs level) in both clipped and non-clipped kidneys as well as in the serum. However, glutathione peroxidase (GSH-Px) activity was decreased in the clipped kidneys but elevated in the non-clipped ones and in the blood. The malondialdehyde (MDA) level was raised in clipped kidneys but not in non-clipped ones nor in the serum. Nitric oxide (NO level) and angiotensin converting enzyme (ACE) activity were increased in both clipped and non-clipped kidneys but not in the serum. Endothelium-dependent and -independent relaxation of aortic rings towards acetylcholine (Ach) and sodium nitroprusside (SNP) were impaired. Treatment with EGb 761 (180 mg/kg/day for 3 weeks) was associated with recovery of GSH-Px activity in clipped kidneys, inhibition of ACE activity in both kidneys and a reduction in the elevated NO level of the non-clipped kidneys, decreased responsiveness to the vasoconstrictor NE and improvement of endothelial function as evidenced by restoration of endothelium-dependent vasorelaxation induced by Ach. The observed beneficial effects of the EGb 761 may be attributed to different factors, including ACE inhibition and maintenance of cellular antioxidant capacity as well as preserving vascular reactivity towards endothelium-dependent and -independent vasodilators while inhibiting responses to vasoconstrictors.