Senescent murine femoral arteries undergo vascular remodelling associated with accelerated stress-induced contractility and reactivity to nitric oxide

This work explored the mechanism of augmented stress-induced vascular reactivity of senescent murine femoral arteries (FAs). Mechanical and pharmacological reactivity of young (12-25 weeks, y-FA) and senescent (>104 weeks, s-FAs) femoral arteries was measured by wire myography. Expression and protein phosphorylation of selected regulatory proteins were studied by western blotting. Expression ratio of the Exon24 in/out splice isoforms of the regulatory subunit of myosin phosphatase, MYPT1 (MYPT1-Exon24 in/out), was determined by polymerase chain reaction (PCR). While the resting length-tension relationship showed no alteration, the stretch-induced-tone increased to 8.3 ± 0.9 mN in s-FA versus only 4.6 ± 0.3 mN in y-FAs. Under basal conditions, phosphorylation of the regulatory light chain of myosin at S19 was 19.2 ± 5.8% in y-FA versus 49.2 ± 12.6% in s-FA. Inhibition of endogenous NO release raised tone additionally to 10.4 ± 1.2 mN in s-FA, whereas this treatment had a negligible effect in y-FAs (4.8 ± 0.3 mN). In s-FAs, reactivity to NO donor was augmented (pD₂  = -4.5 ± 0.3 in y-FA vs. -5.2 ± 0.1 in senescent). Accordingly, in s-FAs, MYPT1-Exon24-out-mRNA, which is responsible for expression of the more sensitive to protein-kinase G, leucine-zipper-positive MYPT1 isoform, was increased. The present work provides evidence that senescent murine s-FA undergoes vascular remodelling associated with increases in stretch-activated contractility and sensitivity to NO/cGMP/PKG system.

Time-Dependent Effects of Individual and Combined Treatments With Nebivolol, Lisinopril, and Valsartan on Blood Pressure and Vascular Reactivity to Angiotensin II and Norepinephrine

Clinical guidelines suggest the combination of 2 drugs as a strategy to treat hypertension. However, some antihypertensive combinations have been shown to be ineffective. Therefore, it is necessary to determine whether differences exist between the results of monotherapy and combination therapy by temporal monitoring of the responses to angiotensin II and norepinephrine, which are vasoconstrictors involved in the development of hypertension. Thus, the purpose of this work was to determine the vascular reactivity to angiotensin II and norepinephrine in spontaneously hypertensive rat (SHR) aortic rings after treatment with valsartan, lisinopril, nebivolol, nebivolol-lisinopril, and nebivolol-valsartan for different periods of time. In this study, male SHR and Wistar Kyoto normotensive (WKY) rats were divided into 7 groups treated for 1, 2, and 4 weeks: (1) WKY + vehicle, (2) SHR + vehicle; (3) SHR + nebivolol; (4) SHR + lisinopril; (5) SHR + valsartan; (6) SHR + nebivolol-lisinopril; and (7) SHR + nebivolol-valsartan. Blood pressure was measured by the tail-cuff method, and vascular reactivity was determined from the concentration-response curve to angiotensin II and norepinephrine in aortic rings. The results showed that the combined and individual treatments reduced mean blood pressure at all times evaluated. All treatments decreased vascular reactivity to angiotensin II; however, in the case of lisinopril and nebivolol-lisinopril, the effect observed was significant up to 2 weeks. All treatments decreased the reactivity to norepinephrine up to week 4. These results show a time-dependent difference in vascular reactivity between the pharmacological treatments, with nebivolol-valsartan and nebivolol-lisinopril being both effective combinations. Additionally, the results suggest crosstalk between the renin-angiotensin and sympathetic nervous systems to reduce blood pressure and to improve treatment efficacy.

Renal protective effect of nebivolol in rat models of acute renal injury: role of sodium glucose co-transporter 2

BACKGROUND

Upregulation of the sodium glucose co-transporter (SGLT2) is implicated in acute renal injury (ARI) progression and is regulated by extracellular signal-regulated kinase (ERK), hypoxia-inducible factor 1 alpha (HIF1α) or prostaglandin E2 (PGE2). This study aimed to assess the possible protective effect of nebivolol on renal ischemia/reperfusion (IR) and glycerol-induced ARI targeting SGLT2 via modulating the ERK-HIF1α pathway.

METHODS

Rats were divided into control, sham, IR or nebivolol-treated group, in which rats were treated with nebivolol (10 mg/kg) for 3 days prior to the induction of IR. The rats were subjected to renal ischemia by bilateral clamping of the pedicles for 45 min, followed by 24 h reperfusion. Another group of rats received the vehicle or nebivolol (10 mg/kg) for 3 days followed by injection of 50% glycerol (8 ml/kg, IM) or saline. Kidney function tests, systolic blood pressure (SBP), oxidative stress markers [malondialdehyde (MDA) and NADPH oxidase] and kidney levels of nitric oxide (NO), inducible nitric oxide synthase (iNOS), HIF1α, ERK phosphorylation and PGE2 were determined. Additionally, renal sections were used for histological grading of renal injury and immunological expression of SGLT2.

RESULTS

ARI rats showed significantly increased SBP, poor kidney function tests, increased oxidative stress, iNOS, NO, HIF1α levels, decreased PGE2 and ERK phosphorylation and upregulation of SGLT2 expression. Nebivolol treatment protected against the kidney damage both on the biochemical and histological levels.

CONCLUSION

Nebivolol has a direct renoprotective effect, at least in part, by down-regulating SGLT2 possibly via modulating HIF1α, ERK activity and PGE2 production.

Risk of incident chronic kidney disease is better reduced by bedtime than upon-awakening ingestion of hypertension medications

This trial investigated whether therapy with the entire daily dose of ≥1 hypertension medications at bedtime exerts a greater reduction in the risk of incident chronic kidney disease (CKD) than therapy with all medications upon awakening. We conducted a prospective, open-label, blinded endpoint trial of 2078 hypertensive patients without CKD (1017 men/1061 women, 53.6 ± 13.7 years of age) randomized to ingest all their prescribed hypertension medications upon awakening (n = 1041) or the entire daily dose of ≥1 of those medications at bedtime (n = 1037). During a 5.9-year median follow-up, 368 participants developed CKD. Patients of the bedtime, compared with the morning, treatment group showed (i) significantly lower asleep blood pressure (BP) mean, greater sleep-time relative BP decline, and attenuated prevalence of non-dipping at the final evaluation (38 vs. 55%; P < 0.001); and (ii) a significantly lower hazard ratio of CKD, adjusted for the significant influential characteristics of age, serum creatinine, urinary albumin, type 2 diabetes, previous cardiovascular event, asleep systolic BP mean, and sleep-time relative systolic BP decline (0.27 (95% confidence interval: 0.21-0.36); event-rate 8.3 vs. 27.1% in the bedtime and morning-treatment groups; P < 0.001). Greater benefit was observed for bedtime than awakening treatment, with angiotensin converting enzyme inhibitors and angiotensin receptor blockers. In hypertensive patients without CKD, ingestion of ≥1 BP-lowering medications at bedtime, mainly those modulating or blocking the effects of angiotensin II, compared with ingestion of all such medications upon-awakening, resulted in improved ambulatory BP control (significant further decrease of asleep BP and enhanced sleep-time relative BP decline) and reduced risk of incident CKD.

Niflumic Acid Attenuated Pulmonary Artery Tone and Vascular Structural Remodeling of Pulmonary Arterial Hypertension Induced by High Pulmonary Blood Flow In Vivo

Calcium-activated chloride channels (CaCCs) play a vital role in regulating pulmonary artery tone during pulmonary arterial hypertension (PAH) induced by high blood flow. The role of CaCCs inhibitor niflumic acid (NFA) in vivo during this process requires further investigation. We established the PAH model by abdominal shunt surgery and treated with NFA in vivo. Fifty rats were randomly divided into normal, sham, shunt, NFA group 1 (0.2 mg/kg), and NFA group 2 (0.4 mg/kg). Pathological changes, right ventricle hypertrophy index, arterial wall area/vessel area, and arterial wall thickness/vessel external diameter were analyzed. Then contraction reactions of pulmonary arteries were measured. Finally, the electrophysiological characteristics of pulmonary arterial smooth muscle cells were investigated using patch-clamp technology. After 11 weeks of shunting, PAH developed, accompanied with increased right ventricle hypertrophy index, arterial wall area/vessel area, and arterial wall thickness/vessel external diameter. In the NFA treatment groups, the pressure and pathological changes were alleviated. The pulmonary artery tone in the shunt group increased, whereas it decreased after NFA treatment. The current density of CaCC was higher in the shunt group, and it was decreased in the NFA treatment groups. In conclusion, NFA attenuated pulmonary artery tone and structural remodeling in PAH induced by high pulmonary blood flow in vivo. CaCCs were involved and the augmented current density was alleviated by NFA treatment.

Bedtime ingestion of hypertension medications reduces the risk of new-onset type 2 diabetes: a randomised controlled trial

AIMS/HYPOTHESIS

We investigated whether therapy with the entire daily dose of ≥ 1 hypertension medications at bedtime exerts greater reduction in the risk of new-onset diabetes than therapy with all medications upon awakening.

METHODS

We conducted a prospective, randomised, open-label, blinded endpoint trial of 2,012 hypertensive patients without diabetes, 976 men and 1,036 women, 52.7 ± 13.6 years of age. Patients were randomised, using a computer-generated allocation table, to ingest all their prescribed hypertension medications upon awakening or the entire daily dose of ≥ 1 of them at bedtime. Investigators blinded to the hypertension treatment scheme of the patients assessed the development of new-onset diabetes.

RESULTS

During a 5.9-year median follow-up, 171 participants developed type 2 diabetes. Patients of the bedtime, compared with the morning-treatment group, showed: (1) significantly lower asleep BP mean, greater sleep-time relative BP decline and attenuated prevalence of non-dipping at the final evaluation (32% vs 52%, p < 0.001); and (2) significantly lower HR of new-onset diabetes after adjustment for the significant influential characteristics of fasting glucose, waist circumference, asleep systolic BP mean, dipping classification and chronic kidney disease (CKD) (unadjusted HR 0.41 [95% CI 0.29, 0.58]; adjusted HR 0.43 [0.31, 0.61]; event-rate 4.8% vs 12.1% with bedtime and morning treatment, respectively; p < 0.001). Greater benefit was observed for bedtime compared with awakening treatment with angiotensin receptor blockers (ARBs) (HR 0.39 [0.22, 0.69]; p < 0.001), ACE inhibitors (0.31 [0.12, 0.79], p = 0.015) and β-blockers (0.35 [0.14, 0.85], p = 0.021).

CONCLUSIONS/INTERPRETATION

In hypertensive patients without diabetes, ingestion of ≥ 1 BP-lowering medications at bedtime, mainly those modulating or blocking the effects of angiotensin II, compared with ingestion of all such medications upon awakening, results in improved ambulatory BP (ABP) control (significant further decrease of asleep BP) and reduced risk of new-onset diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00295542.

FUNDING

This independent investigator-promoted research was supported by unrestricted grants from Ministerio de Ciencia e Innovación (SAF2006-6254-FEDER; SAF2009-7028-FEDER); Xunta de Galicia (PGIDIT03-PXIB-32201PR; INCITE07-PXI-322003ES; INCITE08-E1R-322063ES; INCITE09-E2R-322099ES; 09CSA018322PR); and Vicerrectorado de Investigación, University of Vigo.

Effect of nebivolol on renal nitric oxide availability and tubular function in patients with essential hypertension

AIMS

Nebivolol is a selective β1 -receptor antagonist with vasodilating properties. In patients with essential hypertension, we tested the hypothesis that nebivolol increases systemic and renal nitric oxide (NO) availability using L-N(G) -monomethyl arginine (L-NMMA) as an inhibitor of NO production.

METHODS

In a randomized, placebo-controlled, crossover study, patients with essential hypertension were treated with nebivolol for five days, along with a standardized diet and fluid intake. We examined the acute effects of systemic NO synthase inhibition with L-NMMA on brachial blood pressure (bBP), pulse wave velocity (PWV) and central blood pressure (cBP) estimated by applanation tonometry, glomerular filtration rate (GFR), fractional excretion of sodium (FENa ), urinary excretion of both aquaporin-2 (u-AQP2) and epithelial sodium channels (u-ENaCγ ), and plasma concentrations of nitrate/nitrite (p-NOx ) and vasoactive hormones after five days' treatment with placebo and nebivolol.

RESULTS

Nebivolol significantly reduced PWV, bBP, cBP and plasma renin, angiotensin II and aldosterone concentrations. The renal parameters, p-NOx and plasma arginine vasopressin concentration were not changed by nebivolol. There was no difference between nebivolol and placebo in the response to L-NMMA, with LMMA inducing a similar increase in PWV, bBP and cBP and a similar decrease in GFR, uAQP2 and u-ENaCγ and FENa [mean change -0.62% (95% confidence interval {CI} -0.40 to -0.84) during placebo vs. -0.57% (95% CI -0.46 to -0.68; P = 0.564) during nebivolol treatment]. Vasoactive hormones were changed to a similar extend by L-NMMA during administration of nebivolol and placebo.

CONCLUSIONS

Nebivolol did not change p-NOx , and inhibition of NO synthesis induced the same response in blood pressure, GFR, renal tubular function and vasoactive hormones during nebivolol and placebo. Thus, the data did not support the hypothesis that nebivolol changes vascular and renal NO availability in patients with essential hypertension.