Administration Of L-NAME Research Articles

Partial involvement of nitric oxide synthase in increased pilocarpine-induced sweating in exercise-trained men.

The physiological mechanisms involved in augmented cholinergic agonist-induced sweating in exercise-trained individuals remain unclear. This study hypothesizes that nitric oxide synthase (NOS) contributes to augmented pilocarpine-induced sweating in habitually exercise-trained individuals. Endurance-trained and untrained men (n=15 each) iontophoretically received 1% L-NAME, a NOS inhibitor, and saline (control) in the forearm and then administered 0.001% and 1% pilocarpine to evaluate sweat rate. L-NAME administration attenuated pilocarpine-induced sweating by 10% in the exercise-trained (P = 0.004) but not in untrained (P = 0.764) groups independent of pilocarpine concentrations. Results indicate that NOS partially contributes to increased cholinergic sweating in exercise-trained men.

Therapeutic Effects of Pterocarpus santalinoides Stem Bark Aqueous Extract: Evidence from L-NAME-induced Hypertensive Wistar Rats

Aims: Ethnopharmacological information indicates that the stem bark of Pterocarpus santalinoides is used in traditional medicine to treat many diseases including hypertension. Thus, this study was designed to evaluate the therapeutic effects of the stem bark aqueous extract of Pterocarpus santalinoides (AEPS) in L-NAME-induced hypertensive rats (LNHR). Methodology: Hypertension was induced in normotensive rats by intraperitoneal administration of L-NAME (25 mg/kg/day) for 42 days. Forty-two animals were divided into two main groups: one group of seven rats (group 1) receiving distilled water (10 mL/kg) and another thirty-five rats receiving L-NAME (group 2). After three weeks of treatment, the hypertensive animals (group 2) were divided into five groups of seven rats each. Animals of the first group received distilled water, those of the second group were treated with captopril (20 mg/kg), and the three last groups received the AEPS (50, 100, and 200 mg/kg). These rats were daily treated per os with the above substances for three weeks. At the end of the experimental period (42 days), animals were anesthetized and the blood pressure and heart rate were recorded by invasive method. Afterward, the blood, aorta, and heart of each rat were collected for some biochemical and/or histological examination. Results: L-NAME administration induced hypertension, as associated with left ventricular hypertrophy, dyslipidemia, oxidative stress, hepatic and renal dysfunctions. Aqueous extract administration significantly improved all these metabolic disorders induced by L-NAME. Furthermore, the remodeling of the aortic media after NO deficiency-induced L-NAME has also been improved by Pterocarpus santalinoides aqueous extract. The therapeutic effect of AEPS against L-NAME-induced hypertension could probably be due to its antihypertensive, hypolipidemic, and antioxidant properties. Conclusion: Current results confirmed the empirical use of Pterocarpus santalinoides stem bark for the treatment of hypertension in traditional medicine.

Kefir peptides mitigate L-NAME-induced preeclampsia in rats through modulating hypertension and endothelial dysfunction

AimPreeclampsia is a complex and serious pregnancy disorder that leads to maternal and neonatal mortality worldwide. Kefir peptides (KPs), derived from various prebiotic fermentations in whole milk by kefir grains, were investigated for their potential therapeutic effects. In this study, we used the L-NAME in drinking water to induce a preeclampsia-like condition in spontaneous hypertension stroke-prone (SHRSP) pregnant rats. Main methodsThe rats were assigned to five groups: the normal group (WKY rats), the untreated group (SHRSP rat control pregnant), the L-NAME/Mock group (SHRSP rats fed with L-NAME water), the L-NAME/KPs-LD group (SHRSP rats fed with L-NAME water and low-dose KPs diets), and the L-NAME/KPs-HD group (SHRSP rats fed with L-NAME water and high-dose KPs diets) for a 20-day experiment. Chorioallantois membrane (CAM) assay was applied for ex vivo angiogenesis study of KPs treatment. Key findingsData showed that rats in the L-NAME group developed severe hypertension, proteinuria, placental damage, and embryo resorption. Pre-administration of KPs significantly reduced hypertension, proteinuria, improved generalized endothelial dysfunction, and decreased levels of anti-HIF-1α, sFLT1, anti-TNF-α, and IL-6 in the placenta of SHRSP rats. In ex vivo CAM study, L-NAME administration in chicken embryos resulted in lower vessel density and hemorrhage; however, angiogenesis was observed after KPs-HD treatment. SignificanceThe results indicate that kefir peptides improve renal lesions, prevent renal parenchyma damage, and balance endothelial and angiogenic dysfunction in both maternal and fetal sites in L-NAME-induced SHRSP pregnant rats.

Pathobiological characterization of pulmonary hypertension associated with heart failure with preserved ejection fraction

Abstract Introduction Heart failure with preserved ejection fraction (HFpEF) is an age-related cardiometabolic disease associated with vascular inflammation in cardiac tissue, pulmonary congestion and right ventricular dysfunction. Patients with HFpEF often develop pulmonary hypertension (PH) and right ventricular (RV) hypertrophy. Pulmonary vascular remodeling contributes to combined post- and precapillary PH (CpcPH), which is associated with worse outcome in humans. A recently developed meta-inflammatory murine HFpEF model approximates the characteristics of human HFpEF. Herein, HFpEF is induced by metabolic (high-fat diet (HFD)) and hypertensive stress (inhibition of constitutive NO synthase by Nω-nitro-1-arginomethyl ester (L-NAME)) over a 12-week period of time. With a focus on PH, we have developed a 'three-hit' model based on this model with a supplementary 21- or 42-day hypoxia phase (HFpEF-CpcPH). Methods Adult C57BL/6N mice were fed HFD for 15 or 18 weeks and supplied with L-NAME (0,5g/L or 1g/L) via drinking water, including a final period of 21 or 42 days, respectively, of hypoxia (normobaric, 10 % oxygen) or normoxia. Transthoracic echocardiography was performed using a small animal ultrasound device (Vevo 3100, Visual Sonics) and measurement of right ventricular systolic pressure (RVSP) using a Millar® pressure catheter (Mil-SPR-1000) inserted into the right ventricle. Right ventricular hypertrophy was measured as the ratio of the wet weight of the right ventricle to the left ventricle including the septum (RV/LV+S). Results Administration of HFD and L-NAME had no significant effect on RVSP in either HFpEF-normoxia group (15 weeks (n=8) or 18 weeks (n=5)) compared to the control group (n=8, n=5). 21 days of hypoxia increased RV systolic pressure (RVSP) to 37.05±1.6 (PH, n=8) and 40.33±0.87 mmHg (HFpEF-CpcPH, n=8) respectively, while 42 days of hypoxia caused no further increase (35.1±3.5 mmHg (PH, n=5) and 35.24±3.47 mmgHg (HFpEF-CpcPH, n=4)), respectively. RV hypertrophy (RV/LV+S) was significantly increased after 21 days of hypoxia in HFpEF-CpcPH compared to HFpEF (n=8) (34.42±1.75 vs. 24.93±1.1). Again, 42 days of hypoxia did not lead to a further increase in RV hypertrophy (35.2±3.9 vs. 25.80±4.39) in HFpEF-CpcPH, even though there was a significant difference compared to the HFpEF group. As expected, the heart weight/body weight ratio was significantly increased in HFpEF-CpcPH compared to HFpEF at both time points. However, mice under the prolonged hypoxia phase showed a significantly greater decrease in body weight, which complicates the interpretation of the results. Conclusion In summary, we could show that in the meta-inflammatory HFpEF model no significant PH can be observed within the investigated periods of time. However, a 21 day hypoxia phase was sufficient to induce a HFpEF-CpcPH phenotype. This model provides an important basis to develop new therapeutic approaches.

House cricket protein hydrolysates alleviate hypertension, vascular dysfunction, and oxidative stress in nitric oxide-deficient hypertensive rats.

Edible insects with high protein content and bioactive peptides with health promotion against chronic disease. Deficiency of nitric oxide (NO) contributes to hypertension, a leading cause of cardiovascular diseases and death worldwide. This study assessed the antihypertensive effects of house cricket protein hydrolysates (HCPH) in NO-deficient hypertensive rats. Male Sprague-Dawley rats (n = 12/group) were hypertensive after the administration of Nω-nitro-L-arginine methyl ester (L-NAME) at a dose of 50 mg/kg body weight (BW)/day in drinking water for 7 weeks. The animals were then treated with HCPH (250 or 500 mg/kg BW/day) or lisinopril (Lis) (1 mg/kg BW/day) for the last 4 weeks of L-NAME administration. Blood pressure (BP), vascular function, and structural changes, endothelial NO synthase (eNOS), and p47phox nicotinamide adenine dinucleotide phosphate (NADPH) oxidase protein expression in aortic tissues, plasma nitrate/nitrite, plasma angiotensin-converting enzyme (ACE) activity, and oxidative stress markers in blood and tissues were evaluated. Induction of hypertension resulted in significantly elevated BP, decreased plasma nitrate/nitrite concentration, abolished vascular function, and increased vascular wall thickness. Overproduction of carotid and mesenteric superoxide, increased plasma, heart, and kidney malondialdehyde, and protein carbonyl levels, and increased plasma ACE activity were observed. Down-expression of eNOS with overexpression of p47phox NADPH oxidase subunit was also found in L-NAME hypertensive rats. Oral treatment with HCPH, particularly at a dose of 500 mg/kg BW/day, significantly alleviated these alterations in a manner comparable to that of Lis. HCPH improved vascular function and exerted antihypertensive effects, mainly due to the improvement of NO bioavailability, reduction of oxidative stress, and inhibition of ACE.

Research on Experimental Hypertension in Prague (1966-2009).

The study of ontogenetic aspects of water and electrolyte metabolism performed in the Institute of Physiology (Czechoslovak Academy of Sciences) led to the research on the increased susceptibility of immature rats to salt-dependent forms of hypertension since 1966. Hemodynamic studies in developing rats paved the way to the evaluation of hemodynamic mechanisms during the development of genetic hypertension in SHR. A particular attention was focused on altered renal function and kidney damage in both salt and genetic hypertension with a special respect to renin-angiotensin system. Renal damage associated with hypertension progression was in the center of interest of several research groups in Prague. The alterations in ion transport, cell calcium handling and membrane structure as well as their relationship to abnormal lipid metabolism were studied in a close cooperation with laboratories in Munich, Glasgow, Montreal and Paris. The role of NO and oxidative stress in various forms of hypertension was a subject of a joint research with our Slovak colleagues focused mainly on NO-deficient hypertension elicited by chronic L-NAME administration. Finally, we adopted a method enabling us to evaluate the balance of vasoconstrictor and vasodilator mechanisms in BP maintenance. Using this method we demonstrated sympathetic hyperactivity and relative NO deficiency in rats with either salt-dependent or genetic hypertension. At the end of the first decennium of this century we were ready to modify our traditional approach towards modern trends in the research of experimental hypertension. Keywords: Salt-dependent hypertension o Genetic hypertension o Body fluids o Hemodynamics o Ion transport o Cell membrane structure and function o Renal function o Renin-angiotensin systems.

MLR-1023 Improves Cognition Deficiency and Oxidative Stress in Lipopolysaccharide-Induced Mice Model of Alzheimer’s Disease: Role of PPAR-gamma Receptors and NO-cGMP-KATP Channels Pathway

Background: This study investigates the effects of MLR-1023 on cognitive deficiency and oxidative stress in a lipopolysaccharide (LPS)-induced mouse model. Objectives: The role of PPAR-gamma receptors and the NO- cyclic GMP (cGMP)-KATP channel pathway were examined to identify the likely mechanisms. Methods: The model was established by LPS injection. Behavioral assays included shuttle box and Y-maze tests. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels were then measured in hippocampal tissue. To explore the probable mechanisms, the mice were pre-treated with agonists and antagonists 15 minutes before MLR-1023 (20 - 40 mg/kg, i.p.) administration. Results: Lipopolysaccharide increased the initial latency (IL) time, while MLR-1023 (40 mg) reduced it. Administration of L-NAME, methylene blue, and glibenclamide with MLR-1023 increased IL duration, while L-arginine, sildenafil, and diazoxide reduced it. Lipopolysaccharide reduced the duration of step-through latency (STL), whereas MLR-1023 increased it. L-NAME, methylene blue, and glibenclamide with MLR-1023 reduced STL duration, but L-arginine, sildenafil, and diazoxide increased it. The spontaneous alternation index decreased with LPS, while MLR-1023 increased it. L-NAME, methylene blue, glibenclamide, and GW9662 decreased this index, whereas L-arginine, sildenafil, diazoxide, and pioglitazone increased it. Lipopolysaccharide increased MDA concentration, while MLR-1023 decreased it. L-NAME, methylene blue, and glibenclamide increased MDA concentration, while L-arginine, diazoxide, and pioglitazone decreased it. Lipopolysaccharide reduced SOD activity, which was improved by MLR-1023. L-NAME, methylene blue, glibenclamide, and GW9662 decreased SOD activity, while sildenafil and pioglitazone increased it. Conclusions: MLR-1023 can improve LPS-induced learning-memory impairment and oxidative stress. The KATP/cGMP/NO pathway and PPARγ receptors are involved in this effect.

Endurance exercise boosts Sirtuin 1 and PGC1α in mouse skeletal muscle amid nitric oxide synthesis inhibition

Abstract Sarcopenia is an age-related condition characterised by muscle atrophy and loss of muscle mass. The degradation of myofibrils (atrophy) caused by the activation of myofibrillar degradation proteins, e.g. due to a decrease in nitric oxide (NO) associated with aging, contributes to sarcopenia. NO is involved in glucose and lipid metabolism and mitochondrial proliferation; however, whether endurance exercise increases NO production remains unclear. Therefore, in this study, we examined whether endurance exercise promotes metabolic signalling in muscles during continuous suppression of NO production. Mice were assigned to three groups: control, nitric oxide synthase inhibitor administration (L-NAME), and L-NAME administration plus endurance exercise (L-NAME + Ex). The L-NAME group was administered an NO synthesis inhibitor, and the L-NAME + Ex group was administered the inhibitor and performed exercise. The relative amounts of calmodulin (CaM) and nitric oxide synthase (nNOS) in the soleus muscle were significantly increased in the L-NAME + Ex group compared with those in the control and L-NAME groups. In addition, the relative amounts of Sirtuin 1 (Sirt1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) in the L-NAME + Ex group were significantly higher than those in the L-NAME group and similar to those in the control group. CaM and nNOS are involved in NO production, whereas Sirt1 and PGC1α play facilitatory roles in glucose and lipid metabolism. These findings suggest that endurance exercise may enhance muscle metabolic signalling by increasing NO production, even with the suppression of NO synthesis.

(046) THE ROLE OF ADENOSINE IN THE RELAXANT MECHANISM OF RAT DISTAL VAGINA

Abstract Introduction Adenosine (ADO) is a purinergic neuromodulator that in the male exerts a positive effect on penile erection by controlling smooth muscle (SM) relaxation. However, its role in the relaxant/contractile pathways in the vagina is yet to be investigated. Objective The aim of this study was to characterize the effect of ADO stimulation on SM activity in distal vagina, evaluating its possible effect on the regulation of nitric oxide (NO) pathway using a validated animal model of female Sprague-Dawley rats. Methods The immunolocalization of ADORA2A and ADORA2B in distal vagina tissues was detected by immunohistological staining. In vitro contractility studies on noradrenaline (NA)-precontracted vaginal strips from intact Sprague-Dawley rats were performed; rat smooth muscle cells (rvSMCs) from distal vagina of intact animals were stimulated with ADO for cyclic adenosine monophosphate (cAMP) quantification. mRNA (messenger ribonucleic acid) isolated from vaginal tissue was analyzed by semi-quantitative Reverse Transcriptase-Polymerase Chain Reaction. Results All ADORAs mRNA were expressed in the vaginal tissue, with a significant prevalence of ADORA2B; furthermore, ADORA2A and ADORA2B immunolocalization highlighted that both receptors are highly expressed in the epithelium, in blood capillaries of the vascular bed and in the smooth muscle bundles of vagina wall. In vitro ADO stimulation induced a dose-dependent relaxation (IC50=31.9±2.38 μM), which was significantly reduced by the administration of NO-synthase inhibitor L-NAME; similar effects were observed after the mechanical ablation of endothelium and in vitro administration of the soluble guanylate cyclase inhibitor ODQ, highlighting the pivotal contribution of NO signaling to the ADO relaxant activity. In vitro stimulation with increasing doses of the selective ADO receptor ADORA2A agonist CGS2-1680 induced a dose-dependent relaxation (IC50=132.6±3.47 nM); a similar but less potent relaxant effect was observed with ADORA2B selective agonist BAY60-6583. The relaxing effect induced by ADO on NA-precontracted vaginal strips was completely counteracted by the stimulation with the re-spectively selective ADORA2A and ADORA2B antagonists SHC-442416 and PSB603; a similar effect was induced by ADORA1 selective antagonist SLV320, but not by ADORA3 selective antagonists VUF5574. The mRNA relative expression of enzymes regulating the ADO turnover [adenosine deami-nase (ADA), 5′-nucleotidase (5NTD), AMP deaminase type 1 and type 2 (AMPD1, AMPD2) and adenosine kinase (ADK)] showed a higher expression of genes regulating the de novo ADO/cAMP syn-thesis (ADK, 5NTD), compared to those acting on ADO degradation (ADA, AMPD1, AMPD2). Finally, stimulation of rvSMCs with increasing doses of ADO induced a significant production of intracellular cAMP after 3 minutes (1 and 10 μM). Conclusions These data show that ADO acts as an important relaxant modulator of the vagina through the activation of its receptors, specifically ADORA2A, and the consequent cAMP-dependent adenylate cyclase re-sponse. However, in vitro studies show that ADO also acts trough the NO-dependent pathway. These results therefore demonstrate for the first time a new relaxant pathway in distal vagina, ADO signaling, that results deeply intertwined with the well-known NO pathway. This finding unravels new biological mechanisms underlying vagina physiology that need to be further studied in future research. Disclosure No.

Urine metabolic profile in rats with arterial hypertension of different genesis.

The diversity of pathogenetic mechanisms underlying arterial hypertension leads to the necessity to devise a personalized approach to the diagnosis and treatment of the disease. Metabolomics is one of the promising methods for personalized medicine, as it provides a comprehensive understanding of the physiological processes occurring in the body. The metabolome is a set of low-molecular substances available for detection in a sample and representing intermediate and final products of cell metabolism. Changes in the content and ratio of metabolites in the sample mark the corresponding pathogenetic mechanisms by highlighting them, which is especially important for such a multifactorial disease as arterial hypertension. To identify metabolomic markers for hypertensive conditions of different origins, three forms of arterial hypertension (AH) were studied: rats with hereditary AH (ISIAH rat strain); rats with AH induced by L-NAME administration (a model of endothelial dysfunction with impaired NO production); rats with AH caused by the administration of deoxycorticosterone in combination with salt loading (hormone-dependent form - DOCA-salt AH). WAG rats were used as normotensive controls. 24-hour urine samples were collected from all animals and analyzed by quantitative NMR spectroscopy for metabolic profiling. Then, potential metabolomic markers for the studied forms of hypertensive conditions were identified using multivariate statistics. Analysis of the data obtained showed that hereditary stress-induced arterial hypertension in ISIAH rats was characterized by a decrease in the following urine metabolites: nicotinamide and 1-methylnicotinamide (markers of inflammatory processes), N- acetylglutamate (nitric oxide cycle), isobutyrate and methyl acetoacetate (gut microbiota). Pharmacologically induced forms of hypertension (the L-NAME and DOCA+NaCl groups) do not share metabolomic markers with hereditary AH. They are differentiated by N,N-dimethylglycine (both groups), choline (the L-NAME group) and 1-methylnicotinamide (the group of rats with DOCA-salt hypertension).

#1918 L-NAME accelerates the progression of diabetic kidney disease in mice

Abstract Background and Aims Diabetic kidney disease (DKD) represents one of the major causes of end stage kidney disease worldwide. Despite DN having such a high incidence, mouse models of DN rarely mimic all aspects of the human disease, besides showing very slow progression and sometimes maintenance issues. For this reason, in this project we aimed to develop an accelerated, reproducible and accessible mouse model of DN. Method For our experiments we chose 9-week-old female and male of the leptin receptor knock-out (BKS.Cg-Dock7m +/+ Leprdb/J) mice as type 2 diabetes model. As these mice are still not prone to develop severe kidney injury despite their diabetic condition, we administered the eNOS inhibitor L-NAME for 6 weeks, in order to suppress nitric oxide production and therefore to aggravate kidney damage. Mice were divided in three groups: one vehicle control group, one receiving 40/mg/kg/day of L-NAME and one receiving 80/mg/kg/day of L-NAME dissolved in drinking water. Blood pressure and glomerular filtration rate (GFR) were measured at different time points, together with glycemia and albuminuria. Weight and water intake were also monitored throughout the study. At the end of the experiment, animals were killed and blood and organs collected for further analysis. Results Mice treated with 80 mg/kg/day of L-NAME showed an average increase of 10 mmHg in systolic blood pressure, with a peak of 30 mmHg increase at week 4 of treatment. On the other hand, 40 mg/kg/day of L-NAME did show any effect on blood pressure. Despite the different effect on blood pressure, three weeks of L-NAME administration caused a significant reduction in GFR at both doses, with 5% reduction for the 40 mg-group and 23% for the 80 mg-group. For the 80 mg-group we observed an even further GFR decline after 5 weeks of treatment, with a 28% reduction. No change in GFR was observed in the controls. This decrease in GFR was accompanied by a 10-fold increase in urinary albumin for both experimental groups already after 3 weeks of treatment, which after 4 weeks slightly declined but remained significantly higher than the controls (p < 0.0001). At a histological level, PAS staining of kidney sections revealed that in particular mice treated with 80 mg of L-NAME have enlarged Bowman capsule and glomerular tuft area, besides a reduced glomerular capillary density, coinciding with mesangial expansion. We also stained for overall collagen deposition with picrosirius red staining in order to detect possible fibrosis formation. We then observed that 80 mg of L-NAME accelerates interstitial fibrosis in the cortical area of the kidney, which also overlapped with an increased deposition of collagen I. This increase in collage I was also detected in kidney cortex of mice treated with 40 mg of L-NAME, although their overall collagen deposition and therefore fibrotic tissue did not differ from the control group. The medullar region of kidneys was also analyzed, but none of the two experimental groups revealed significant differences in terms overall collagen or collagen I deposition. Unlike mesangial expansion and fibrosis, L-NAME did not influence microphages infiltration, as revealed by CD68 staining in kidney sections. This suggests that L-NAME treatment does not accelerate kidney damage by triggering or accelerating inflammatory processes. This was also confirmed by qPCR analysis of kidney tissue, where the expression pro-inflammatory markers, such as IL1β, TNFα and MCP-1, did not change in the experimental groups. Conclusion Our results show that L-NAME considerably accelerates the progression of DKD in diabetic mice, with GFR declining and progressive albuminuria already after 3 weeks. Such disfunction is confirmed at 6 weeks by histological analysis, where mesangial expansion and fibrosis were detected. This model can be used to assess the therapeutic potential of novel interventions aimed to slow down DKD.

Effects of phosphodiesterase 5 inhibitor (viagra) on biochemical parameters of l-name-induced testicular toxicity in adult male wistar rats

Testicular toxicity is a growing concern in today's world, with various factors contributing to its prevalence. Nitric oxide (NO) imbalance, often induced by N (gamma)-nitro-L-arginine methyl ester (L-NAME), is a significant factor associated with testicular dysfunction. Sildenafil (Viagra), a phosphodiesterase type 5 inhibitor, has shown promise in improving testicular function by modulating NO levels. This study aimed to investigate the role of Sildenafil (Viagra) on biochemical parameters of L-NAME-induced testicular toxicity in Wistar rats. Twenty-four adult male Wistar rats were divided into four groups: Control (physiological saline-treated), L-Name (L-Name-induced testicular toxicity), PDE (Sildenafil-treated), and L-Name + Sildenafil (co-treatment) and subjected to a 56-day treatment regimen. At the end of the administration, the animals were sacrificed, tissues collected and biochemical and histological assessments were performed. Findings revealed that L-Name administration led to a significant decreased in nitric oxide levels, follicle stimulating hormone, luteinizing hormone, testosterone and increase in oxidative stress when compared to the control group. Furthermore, histological analysis demonstrated structural alterations in the testes of L-NAME-treated rats, indicative of testicular toxicity. Rats treated with Sildenafil showed a slight reversal of these adverse effects. Also, slight reversals of impaired spermatogenesis were evident in the co-treatment group. This study provides compelling evidence for the potential therapeutic role of sildenafil in ameliorating L-NAME-induced testicular toxicity in adult male Wistar rats.

Inhibition of activin receptor 2 signalling ameliorates metabolic dysfunction–associated steatotic liver disease in western diet/L-NAME induced cardiometabolic disease

ObjectiveBlockade of activin 2 receptor (ACVR2) signaling has been shown to improve insulin sensitivity and aid in weight loss. Inhibition of ACVR2 signaling restores cardiac function in multiple heart failure models. However, its potential in the treatment of obesity-related cardiometabolic disease remains unknown. Here, we investigated targeting ACVR2 signaling in cardiometabolic disease manifested with metabolic dysfunction–associated steatotic liver disease (MASLD). MethodsMice were fed a high-fat, high-sugar diet combined with the administration of nitric oxide synthase inhibitor L-NAME in drinking water, which causes hypertensive stress. For the last eight weeks, the mice were treated with the soluble ACVR2B decoy receptor (sACVR2B-Fc). ResultssACVR2B-Fc protected against the development of comorbidities associated with cardiometabolic disease. This was most pronounced in the liver where ACVR2 blockade attenuated the development of MASLD including cessation of pro-fibrotic activation. It also significantly reduced total plasma cholesterol levels, impeded brown adipose tissue whitening, and improved cardiac diastolic function. In vitro, ACVR2 ligands activin A, activin B and GDF11 induced profibrotic signaling and the proliferation of human cardiac fibroblasts. ConclusionsBlockade of ACVR2B exerts broad beneficial effects for therapy of cardiometabolic disease. By reducing obesity, ameliorating cardiovascular deterioration and restraining MASLD, blockade of ACVR2B signaling proves a potential target in MASLD and its comorbidities.

Sacubitril/Valsartan Alleviates Cardiac Remodeling and Dysfunction in L-NAME-Induced Hypertension and Hypertensive Heart Disease.

There is ample evidence on the benefit of angiotensin receptor-neprilysin inhibitors (ARNIs) in heart failure, yet data regarding the potential protective action of ARNIs in hypertensive heart disease are sparse. The aim of this study was to show whether an ARNI exerts a protective effect in a model of Nω-nitro-L-arginine methyl ester (L-NAME)-induced hypertension with a hypertensive heart and to compare this potential benefit with an angiotensin-converting enzyme inhibitor, captopril. Five groups of adult male Wistar rats were studied (14 per group) for four weeks: untreated controls; ARNI (68 mg/kg/day); L-NAME (40 mg/kg/day); L-NAME treated with ARNI; and L-NAME treated with captopril (100 mg/kg/day). L-NAME administration induced hypertension, accompanied by increased left ventricular (LV) weight and fibrotic rebuilding of the LV in terms of increased concentration and content of hydroxyproline in insoluble collagen and in total collagen and with a histological finding of fibrosis. These alterations were associated with a compromised systolic and diastolic LV function. Treatment with either an ARNI or captopril reduced systolic blood pressure (SBP), alleviated LV hypertrophy and fibrosis, and prevented the development of both systolic and diastolic LV dysfunction. Moreover, the serum levels of prolactin and prolactin receptor were reduced significantly by ARNI and slightly by captopril. In conclusion, in L-NAME-induced hypertension, the dual inhibition of neprilysin and AT1 receptors by ARNI reduced SBP and prevented the development of LV hypertrophy, fibrosis, and systolic and diastolic dysfunction. These data suggest that ARNI could provide protection against LV structural remodeling and functional disorders in hypertensive heart disease.

Gender-Specific Renoprotective Pathways in αMUPA Transgenic Mice Subjected to Acute Kidney Injury.

Acute kidney injury (AKI) is a serious health concern with high morbidity and high mortality worldwide. Recently, sexual dimorphism has become increasingly recognized as a factor influencing the severity of the disease. This study explores the gender-specific renoprotective pathways in αMUPA transgenic mice subjected to AKI. αMUPA transgenic male and female mice were subjected to ischemia-reperfusion (I/R)-AKI in the presence or absence of orchiectomy, oophorectomy, and L-NAME administration. Blood samples and kidneys were harvested 48 h following AKI for the biomarkers of kidney function, renal injury, inflammatory response and intracellular pathway sensing of or responding to AKI. Our findings show differing responses to AKI, where female αMUPA mice were remarkably protected against AKI as compared with males, as was evident by the lower SCr and BUN, normal renal histologically and attenuated expression of NGAL and KIM-1. Moreover, αMUPA females did not show a significant change in the renal inflammatory and fibrotic markers following AKI as compared with wild-type (WT) mice and αMUPA males. Interestingly, oophorectomized females eliminated the observed resistance to renal injury, highlighting the central protective role of estrogen. Correspondingly, orchiectomy in αMUPA males mitigated their sensitivity to renal damage, thereby emphasizing the devastating effects of testosterone. Additionally, treatment with L-NAME proved to have significant deleterious impacts on the renal protective mediators, thereby underscoring the involvement of eNOS. In conclusion, gender-specific differences in the response to AKI in αMUPA mice include multifaceted and keen interactions between the sex hormones and key biochemical mediators (such as estrogen, testosterone and eNOS). These novel findings shed light on the renoprotective pathways and mechanisms, which may pave the way for development of therapeutic interventions.

Combined vaccines against angiotensin II receptor type 1 and alpha 1D-adrenergic receptor for hypertension.

Compared with monotherapy, combination therapy with multiple antihypertensive drugs has demonstrated superior efficacy in the management of hypertension. The aim of this study was to explore the efficacy of multitarget combined vaccines in achieving simultaneous antihypertensive and target organ protection effects. Our team has developed ATRQβ-001 and ADRQβ-004 vaccines targeting Ang II type 1 receptor (AT1R) and α1D-adrenergic receptor (α1D-AR), respectively. In NG-nitroarginine methyl ester ( l -NAME) + abilities spontaneously hypertensive rats (SHRs) model, SHRs were simultaneously inoculated with ATRQβ-001 and ADRQβ-004 vaccines. Histological and biochemical analyses were performed to evaluate the antihypertensive effects and target organ protection of the ATRQβ-001 and ADRQβ-004 combined vaccines in comparison with those of the single vaccine. Both ATRQβ-001 and ADRQβ-004 vaccines induced robust antibody production, resulting in persistent high antibody titers in rats. Notably, the combined administration of both vaccines significantly decreased SBP in SHRs compared with treatment with a single vaccine, both before and after l -NAME administration. Furthermore, the combined vaccine regimen demonstrated superior efficacy in protecting against vascular remodeling, myocardial hypertrophy and fibrosis, and kidney injury in SHRs. Mechanistically, the combined vaccines exhibited significantly downregulated the expression of angiotensin II type 1 receptor (AT1R) and α1D-adrenergic receptor (α1D-AR). Importantly, no apparent immune-related adverse effects were observed in animals immunized with the combined vaccines. Preliminary findings from this investigation suggest that co-administration of the novel ATRQβ-001 and ADRQβ-004 vaccines holds potential as a groundbreaking therapeutic strategy for managing hypertension.

Chronic Cinacalcet improves skin flap survival in rats: the suggested role of the nitric oxide pathway.

Cinacalcet is a calcimimetic medicine that has been used to treat secondary hyperparathyroidism and parathyroid cancer. Various studies have proposed the positive role of calcium and its receptor in skin wound healing. Furthermore, Cinacalcet interacts with other skin repair-related mechanisms, including inflammation and nitric oxide pathways. The present study evaluated the effect of Cinacalcet on the random-pattern skin flap survival. Eighty-four Wistar male rats were used. Multiple doses of Cinacalcet (30, 3, 1, 0.3, and 0.05 mg/kg) were used in 3 different routes of administration before the surgery. Histopathological evaluations, quantitative assessment of IL-6, TNF-α, and nitric oxide (NO), and the expression of calcium-sensing receptor (CaSR) and E-cadherin were evaluated in the skin tissue. To assess the role of NO, a NO synthase inhibitor, N-nitro-L-arginine methyl ester hydrochloride (L-NAME), was used, and histopathological effects were investigated. Cinacalcet pretreatment at the IP chronic 1 mg/kg dose significantly increased the skin flap survival rate and enhanced the NO tissue level compared to the control. However, the administration of L-NAME abolished its protective effects. IP Chronic 1 mg/kg of Cinacalcet could also decline the levels of IL-6 and TNF-α and also increase the expression of CaSR and E-cadherin in the flap tissue compared with the control group. Chronic Cinacalcet at 1 mg/kg could improve skin flap survival, probably mediated by the CaSR, NO, and inflammation-related pathways.

Improvement Prospects of Lycopene Supplementation in the L-NAME Toxicity on the Male Wistar Rat Reproductive System

Non-selective nitric oxide synthase inhibitors, such as N (G)-nitro-L-arginine Methyl Ester (L-NAME), are typically prescribed to treat spinal injuries and hypotension. Many physiological processes, including the regulation of reproductive hormones, are ty pically linked to it. Bioactivity in physiological systems is influenced by the antioxidant lycopene. This study sought to determine the imp act of lycopene supplementation and L-NAME administration on gonadal hormones and sperm parameters. Twenty male Wistar rats were used for this study and were divided into four groups containing 5 rats each. L-NAME (5mg/kg) was administered through drinking water and Lycopene (5mg/kg) was supplemented through oral gavage for four weeks. Using established protocols with Elisa Kits, plasma hormone levels were ascertained. Estradiol did not differ substantially across all groups, however, the group that received L-NAME had lower plasma concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and nitric oxide (NO). Lycopene supplements raised testosterone, FSH, LH, and NO levels while not affecting estradiol. The sperm profile was altered with L-NAME but ameliorated in Lycopene supplementation. We conclude that lycopene has the potential to protect against hormonal imbalance and male infertility resulting from Nitric oxide synthase (NOS) inhibition.

Preventing spontaneous cerebral microhemorrhages in aging mice: a novel approach targeting cellular senescence with ABT263/navitoclax.

Emerging evidence from both clinical and preclinical studies underscores the role of aging in potentiating the detrimental effects of hypertension on cerebral microhemorrhages (CMHs, or cerebral microbleeds). CMHs progressively impair neuronal function and contribute to the development of vascular cognitive impairment and dementia. There is growing evidence showing accumulation of senescent cells within the cerebral microvasculature during aging, which detrimentally affects cerebromicrovascular function and overall brain health. We postulated that this build-up of senescent cells renders the aged cerebral microvasculature more vulnerable, and consequently, more susceptible to CMHs. To investigate the role of cellular senescence in CMHs' pathogenesis, we subjected aged mice, both with and without pre-treatment with the senolytic agent ABT263/Navitoclax, and young control mice to hypertension via angiotensin-II and L-NAME administration. The aged cohort exhibited a markedly earlier onset, heightened incidence, and exacerbated neurological consequences of CMHs compared to their younger counterparts. This was evidenced through neurological examinations, gait analysis, and histological assessments of CMHs in brain sections. Notably, the senolytic pre-treatment wielded considerable cerebromicrovascular protection, effectively delaying the onset, mitigating the incidence, and diminishing the severity of CMHs. These findings hint at the potential of senolytic interventions as a viable therapeutic avenue to preempt or alleviate the consequences of CMHs linked to aging, by counteracting the deleterious effects of senescence on brain microvasculature.

Bradycardic effect of endothelial-specific bradykinin type-II receptors overexpression in mice: impact on blood pressure

Abstract Background/Introduction Polymorphisms of the gene encoding for the bradykinin type-II receptors (B2R) has been shown to decrease the expression of B2R and increased vascular resistance and blood pressure in humans. Purpose We aimed to study the role of endothelial B2R on systolic blood pressure (SBP) and heart rate (HR) using a novel mice model with endothelial-specific B2R overexpression (B2tg) as compared with transgene negative littermates (B2n) and on differential expression of proteins potentially relevant to vascular tension. Methods Human and murine B2R expression levels were quantified by rtPCR. Thoracic aortic tissues were used for vascular reactivity studies and proteomic analysis. SBP and HR were measured by the tail-cuff method at baseline, after administration of the COX inhibitor diclofenac (10 mg/kg/day), B2R antagonist icatibant (1 mg/kg) or NOS inhibitor L-NAME (100 mg/kg/day). Results In aortic tissues of B2tg human B2R were exclusively expressed (n=6, P=0.0005), while murine B2R expression levels remained unchanged. Similar results were found in skeletal muscle tissues used as an estimate for resistance vessels. Aortic ring studies revealed a concentration-dependent constriction to bradykinin in wild-type mice (maximal vasoconstriction 9.6±3.0%, n=5) whereas aortic rings of B2tg showed concentration-dependent relaxation (-27.4±4.1%, n=12). SBP was significantly lower in B2tg (125.0 ±1.6 mmHg) as compared to B2n (129.9±1.1 mmHg, n=9, P=0.03). Diclofenac treatment slightly but not significantly reduced SBP in B2n (to 125.5±2.4 mmHg, P=0.09) and in B2tg (to 119.8±2.8 mmHg, n=9, P=0.12), however the difference in SBP remained (P=0.03). In a pilot study, L-NAME administration did also not change the SBP difference between B2n and B2tg (9.9±10.3 mmHg, n=3-4). In contrast, icatibant administration abolished the difference between the groups (B2n 128.6±4.6 vs B2tg 128.3±2.0 mmHg, n=8, P=ns) suggesting the involvement of endothelial B2R in SBP reduction. Interestingly, in the same mice, HR was significantly lower in B2tg (571.4±20.8 bpm) as compared to B2n (626.7±13.7 bpm, P=0.02). While diclofenac didn’t affect HR, icatibant significantly increased HR to (630.8±21.8 bpm in B2tg and 685.5±16.4 bpm in B2n, n=8, P=0.01). Only in B2tg, there was a significant strong correlation between SBP and HR (r=0.76, P=0.016). Analysis of proteomic data revealed differential upregulation of proteins related to cell adhesion (CD44), extracellular matrix (hyaluronidase), and differential downregulation of proteins related to oxidative stress (superoxide dismutase) in B2tg. Conclusion Endothelial B2R overexpression reduces SBP and HR. SBP reduction is not dependent on two major vascular pathways stimulated by products of NOS and COX but appears to be related to endothelial B2R-dependent HR reduction. Hence, agonism at B2R could be a valuable target for development of new cardiovascular drugs.