Melatonin, refractory hypertension, myocardial ischemia and other challenges in nightly blood pressure lowering

Nutraceuticals and blood pressure control: a European Society of Hypertension position document

: High-normal blood pressure (BP) is associated with an increased risk of cardiovascular disease, however the cost-benefit ratio of the use of antihypertensive treatment in these patients is not yet clear. Some dietary components and natural products seems to be able to significantly lower BP without significant side effects. The aim of this position document is to highlight which of these products have the most clinically significant antihypertensive action and wheter they could be suggested to patients with high-normal BP. Among foods, beetroot juice has the most covincing evidence of antihypertensive effect. Antioxidant-rich beverages (teas, coffee) could be considered. Among nutrients, magnesium, potassium and vitamin C supplements could improve BP. Among nonnutrient-nutraceuticals, soy isoflavones could be suggested in perimenopausal women, resveratrol in insulin-resistant patients, melatonin in study participants with night hypertension. In any case, the nutracutical approach has never to substitute the drug treatment, when needed.

Melatonin attenuates hypertension and oxidative stress in a rat model of L-NAME-induced gestational hypertension

Preeclampsia is a life-threatening multiorgan systemic disease with manifestations including gestational hypertension, oxidative stress, and vascular dysfunction. We aimed to evaluate the therapeutic effects of melatonin on an L-NAME (NLG-nitro-l-arginine methyl ester)-induced rat preeclampsia model. During gestation, L-NAME was added to drinking water at 50 mg/kg/day from gestation day (GD) 8. Rats received the combination of L-NAME with melatonin (10 mg/kg/day), or aspirin (1.5 mg/kg/day), and rats that received only L-NAME or no treatments were used as controls. Aspirin was mixed with rodent chow and melatonin was administered intraperitoneally. Blood pressure and urine protein content were monitored every 3 days. On GD19, blood samples were collected for biochemical analysis. Compared to untreated L-NAME rats, melatonin led to markedly lowered blood pressure and urine protein content, and recovery in the fetus alive ratio, fetal weight, and the fetal weight/placental weight ratio. Compared to untreated L-NAME rats, plasma antioxidant capacity and plasma malondialdehyde were increased and decreased by melatonin, respectively, in L-NAME rats. Melatonin treatment also reduced sFlt-1, increased PlGF, and decreased the sFlt-1/PlGF ratio. In the placenta, melatonin also reduced sFlt-1 levels and increased Nrf2, PlGF, and HO-1 levels. We have demonstrated in a rat model of preeclampsia that melatonin exerts significant protective effects through lowering blood pressure and reducing oxidative stress.

Nutraceuticals with a clinically detectable blood pressure-lowering effect: a review of available randomized clinical trials and their meta-analyses

AIMS

The aim of the present study was to review and comment on the available evidence on nutraceuticals with a clinically demonstrable blood pressure (BP)-lowering effect.

METHODS

We reviewed studies published in the English language from 1990 to 2015 on dietary supplements or nutraceuticals claiming to show an effect on human BP. An initial list of possibly effective agents and studies was obtained from the online reference, the Natural Medicine Comprehensive Database. Using PubMed, we searched agents identified from this list using the MeSH terms 'hypertension', 'blood pressure', 'dietary supplement' and 'nutraceuticals', alone and in combination. We then focused our attention on meta-analyses and randomized clinical trials.

RESULTS

Beyond the well-known effects on BP of the Dietary Approaches to Stop Hypertension (DASH) and the Mediterranean diet, a large number of studies have investigated the possible BP-lowering effect of different dietary supplements and nutraceuticals, most of which are antioxidant agents with a high tolerability and safety profile. In particular, a relatively large body of evidence supports the use of potassium, magnesium, L-arginine, vitamin C, cocoa flavonoids, beetroot juice, coenzyme Q10, controlled-release melatonin and aged garlic extract. The antihypertensive effect of all these nutraceuticals seems to be dose related and the overall tolerability is good.

CONCLUSION

Some nutraceuticals might have a positive impact on BP in humans. Further clinical research is needed, to identify from the available active nutraceuticals those with the best cost-effectiveness and risk-benefit ratio for widespread and long-term use in the general population with a low-added cardiovascular risk related to uncomplicated hypertension.

Administration-time differences in effects of hypertension medications on ambulatory blood pressure regulation

Specific features of the 24-h blood pressure (BP) pattern are linked to progressive injury of target tissues and risk of cardiovascular disease (CVD) events. Several studies have consistently shown an association between blunted asleep BP decline and risk of fatal and nonfatal CVD events. Thus, there is growing focus on ways to properly control BP during nighttime sleep as well as during daytime activity. One strategy, termed chronotherapy, entails the timing of hypertension medications to endogenous circadian rhythm determinants of the 24-h BP pattern. Significant and clinically meaningful treatment-time differences in the beneficial and/or adverse effects of at least six different classes of hypertension medications, and their combinations, are now known. Generally, calcium channel blockers (CCBs) are more effective with bedtime than morning dosing, and for dihydropyridine derivatives bedtime dosing significantly reduces risk of peripheral edema. The renin-angiotensin-aldosterone system is highly circadian rhythmic and activates during nighttime sleep. Accordingly, evening/bedtime ingestion of the angiotensin-converting enzyme inhibitors (ACEIs) benazepril, captopril, enalapril, lisinopril, perindopril, quinapril, ramipril, spirapril, trandolapril, and zofenopril exerts more marked effect on the asleep than awake systolic (SBP) and diastolic (DBP) BP means. Likewise, the bedtime, in comparison with morning, ingestion schedule of the angiotensin-II receptor blockers (ARBs irbesartan, olmesartan, telmisartan, and valsartan exerts greater therapeutic effect on asleep BP, plus significant increase in the sleep-time relative BP decline, with the additional benefit, independent of drug terminal half-life, of converting the 24-h BP profile into a more normal dipping pattern. This is the case also for the bedtime versus upon-awakening regimen of combination ARB-CCB, ACEI-CCB, and ARB-diuretic medications. The chronotherapy of conventional hypertension medications constitutes a new and cost-effective strategy for enhancing the control of daytime and nighttime SBP and DBP levels, normalizing the dipping status of their 24-h patterning, and potentially reducing the risk of CVD events and end-organ injury, for example, of the blood vessels and tissues of the heart, brain, kidney, and retina.

Night-time exogenous melatonin administration may be a beneficial treatment for sleeping disorders in beta blocker patients

Sleep disorders are the common side effects of beta blockers. Beta blockers have been shown to reduce the production of melatonin via specific inhibition of adrenergic beta1-receptors. Exogenous melatonin, taken in the evening as a supplement, could reduce the central nervous system (CNS) side effects (sleep disorder) associated with beta-adrenergic receptor blockers as well as the potential risk associated with reduction of the melatonin synthesis.

A risk score to predict silent myocardial ischemia in patients with coronary artery disease under aspirin therapy presenting with upper gastrointestinal hemorrhage

BACKGROUND

Silent myocardial ischemia (SMI) is a relatively common complication in patients with coronary artery disease (CAD) under aspirin therapy presenting with upper gastrointestinal hemorrhage (UGIH).

AIM

This study was conducted to develop and prospectively validate a risk prediction score to identify SMI in patients undergoing aspirin therapy for CAD presenting with UGIH in the emergency department (ED).

METHODS

This was a 2-phase noninterventional study. In the derivation phase, adults with CAD under aspirin therapy (100 mg once daily) presenting to the ED with UGIH were retrospectively recruited. By multiple logistic regression analysis, we derived a risk score from 224 patients that predicts the patients' risk of SMI. In the validation phase, we prospectively validated this score using receiver operating characteristic curves with data from 110 patients. We also developed a fast-track screening procedure from this score.

RESULTS

There were 56 patients (25.0%) and 29 patients (26.4%) with SMI in the derivation and validation sets, respectively. Independent multivariate predictors of SMI were age of older than 75 years, severity of CAD, systolic blood pressure of less than 110 mm Hg, diastolic blood pressure of less than 85 mm Hg, hematocrit of less than 30%, and blood urea nitrogen-creatinine ratio of more than 30. The area under receiver operating characteristic curve for the rule was 0.93 in the derivation set and 0.96 in the validation set. At the cutoff value of 5 points or higher, the sensitivity and specificity of the fast-track screening procedure for SMI were 96.6% and 86.4%, respectively. The positive and negative predictive values were 71.8% and 98.6%, respectively.

CONCLUSIONS

This simple risk prediction score is easily calculated and is based on rapidly available clinical and laboratory data in the ED. It can be used to stratify patients undergoing aspirin therapy for CAD presenting with UGIH by risk of SMI.

Melatonin: therapeutic and clinical utilization

Melatonin, acting through melatonin receptors, is involved in numerous physiological processes including circadian entrainment, blood pressure regulation, oncogenesis, retinal physiology, seasonal reproduction, ovarian physiology, immune function and most recently in inducing osteoblast differentiation. Moreover, melatonin was proved to be a potent-free radical scavenger and a broad-spectrum antioxidant. More research is required into the effects of therapeutically modulating the melatoninergic system on circadian haemodynamics and rhythm under varying physiopathological conditions and the possible impact on morbidity and mortality in humans.

Silent myocardial ischemia in coronary artery disease patients under aspirin therapy presenting with upper gastrointestinal hemorrhage

AIM

To identify the risk factors for myocardial ischemia in patients undergoing aspirin therapy for coronary artery disease (CAD) presenting with upper gastrointestinal hemorrhage and to ascertain the impacts on mortality and length of hospital stay.

METHODS

Adults with CAD under aspirin therapy (100 mg once daily) presenting to the emergency department with upper gastrointestinal hemorrhage were retrospectively recruited and divided into group A (ischemia) and group B (non-ischemia). Charts were reviewed for various demographic, laboratory and outcome data. Electrocardiograms were interpreted blindly by a senior cardiologist.

RESULTS

A total of 152 patients, 72.4% men and 27.6% women, were analyzed. Of these, 31 patients had ischemia and were placed in group A and 121 patients did not have ischemia and were in group B. Independent multivariate predictors of myocardial ischemia were history of triple vessel disease (odds ratio [OR], 9.24; 95% confidence interval [CI], 2.00-42.72), lower diastolic blood pressure (OR, 1.09; 95% CI, 1.02-1.16), lower hematocrit (OR, 1.41; 95% CI, 1.16-1.70), and higher blood urea nitrogen (OR, 0.94; 95% CI, 0.89-0.98). Patients with myocardial ischemia had significantly longer hospital length of stay (8.7 +/- 4.0 days vs 5.4 +/- 1.7 days; P < 0.001) and higher in-hospital mortality (16.1%vs 2.5%; P < 0.01) than did those without myocardial ischemia.

CONCLUSION

Myocardial ischemia is a relatively common complication in CAD patients under aspirin therapy presenting with upper gastrointestinal hemorrhage. A history of CAD with triple vessel disease, higher blood urea nitrogen, lower diastolic blood pressure and lower hematocrit may help identify patients who are at increased risk of myocardial ischemia, which tends to be associated with higher in-hospital mortality and increased length of hospital stay.