Plasma levels of matrix metalloproteinase-9 are elevated in individuals with hypertensive crisis.

BACKGROUND: Matrix metalloproteinase-9 (MMP-9) participates in the degradation of components of the extracellular matrix and it is involved in vascular remodeling and vasomotor changes. The aim of this study was to investigate the plasma levels of MMP-9 in acute vascular alterations due to hypertensive crisis. METHODS: This cross-sectional study was performed in 40 normotensive (NT) and 58 controlled hypertensive subjects (CHyp) followed up in outpatient clinic. Moreover, 57 patients with hypertensive emergency (HypEmerg) and 43 in hypertensive urgency (HypUrg), seen in emergency department, were also included. Hypertensive crisis was divided into HypEmerg, which was characterized by levels of systolic blood pressure (BP) ≥ 180 mmHg and/or diastolic BP ≥ 120 mmHg complicated with target-organ damage (TOD), and HypUrg, defined by BP elevation without TOD. Univariate and multivariate regression analysis was performed to identify the influence of independent variables on MMP-9 levels. A p-value < 0.05 was considered statistically significant. RESULTS: The mean age was 43.5 years in the NT group (11 men); 57.7 years in the CHyp group (29 men); 59.4 years in the HypUrg group (21 men) and 62.4 years in the HypEmerg group (31 men). The age was statistically different in the NT group compared to other 3 groups. The mean BP was 116.5 ± 13.9/72.4 ± 10.6 mmHg for NT, 123.2 ± 12.6/79 ± 9.2 for CHyp, 194.1 ± 24.3/121.4 ± 17.3 for HypUrg and 191.6 ± 34.3/121.7 ± 18.8 mmHg for HypEmerg, respectively (p-value< 0.0001 between groups). MMP-9 levels were statistically different between the HypEmerg (2.31 ± 0.2 ng/mL) and HypUrg groups (2.17 ± 0.3 ng/mL) compared to the NT (1.94 ± 0.3 ng/mL) (p-value < 0.01 and p-value < 0.05, respectively) and CHyp groups (1.92 ± 0.2 ng/mL) (p-value < 0.01). Uric acid was the only independent variable for predicting MMP-9 levels (p-value = 0.001). CONCLUSION: MMP-9 concentrations are significantly higher in the hypertensive crisis groups (urgency and emergency) compared to the control groups. Therefore, MMP-9 may be a biomarker or mediator of pathophysiologic pathways in cases of acute elevations of blood pressure.

Effects of transcutaneous electrical nerve stimulation (TENS) on arterial stiffness and blood pressure in resistant hypertensive individuals: study protocol for a randomized controlled trial.

BACKGROUND: Resistant hypertension (RH) treatment requires an adequate and intense therapeutic approach. However, the results are not always satisfactory despite intensive treatment. Of the different pathophysiological mechanisms involved in the pathogenesis of RH, sympathetic overstimulation and therapies that block the sympathetic system have been widely studied. These approaches, however, are invasive and expensive. Another possible approach is by transcutaneous electrical nerve stimulation (TENS), a noninvasive method that modulates activity by using low-frequency transcutaneous electrical stimulation to inhibit primary afferent pathways. Thus, the current study will evaluate the effect of applying TENS in the cervicothoracic region of subjects with RH and will seek to develop a new low-cost and readily available therapy to treat this group of hypertensive individuals. METHODS/DESIGN: This is a randomized, single blind (subject), parallel-assignment study controlled with a sham group and including participants aged 40 to 70 years with resistant hypertension. The trial has two arms: the treatment and control (sham group). The treatment group will be submitted to the stimulation procedure (TENS). The sham group will not be submitted to stimulation. The primary outcomes will be a reduction in the peripheral blood pressure and adverse events. The secondary outcomes will be a reduction the central blood pressure. The study will last 30 days. The sample size was calculated assuming an alpha error of 5 % to reject the null hypothesis with a statistical power of 80 %, thereby resulting in 28 participants per group (intervention versus sham). DISCUSSION: In recent decades, RH has become very common and costly. Adequate control requires several drugs, and in many cases, treatment is not successful. Sympathetic nervous system inhibition by renal denervation and central inhibition have significant effects in reducing BP; however, these treatments are costly and invasive. Another type of sympathetic nervous system inhibition can also be noninvasively achieved by electric current. Therefore, the application of TENS may be a new therapeutic option for treating resistant hypertensive individuals. TRIAL REGISTRATION: Clinical Trials NCT02365974.

Endothelial Changes in Individuals with Prehypertension.

INTRODUCTION: Prehypertension is considered a precursor of systemic arterial hypertension and a predictor of morbidity-mortality due to cardiovascular diseases, which are the main causes of death in Brazil and the world. Thus, early diagnosis and the adoption of therapeutic measures in cases of prehypertension can reduce cardiovascular risk. The aim of the present study was to perform a selective review of the literature to identify and discuss early endothelial changes in individuals with pre-hypertension. RESULTS AND DISCUSSION: The findings indicate an increase in ET-1-mediated vasoconstrictor tone in prehypertension, with endothelial-dependent vasodilatation impairment. Moreover, significantly high levels of angiotensin, arginine and vasopressin were found in this group of patients. A reduction in endothelial fibrinolytic capacity was another important change found in patients with prehypertention and was associated with an increased risk for atherothrombotic events. CONCLUSION: The present findings demonstrate endothelial changes in individuals with prehypertension that contribute to the development of arterial hypertension as well as a high risk for cardiovascular events, underscoring the importance of the early adoption of optimized therapeutic measures for this population.

How to Investigate the Vascular Changes in Resistant Hypertension.

The pathophysiological mechanism of resistant hypertension (RH) is related to increased vascular smooth muscle tone and blood volume, exacerbation of the activity of the sympathetic system and hyperactivity of the renin-angiotensin-aldosterone system (RAAS), all of which are important regulatory mechanisms of blood pressure. Hypertension is associated with reduced endothelial homeostasis, and thus the best treatment would not only reduce blood pressure but also reverse endothelial injury. RH is associated with more serious vascular dysfunction, assessed by endothelium-dependent vasodilation and the presence of serum biomarkers. Arterial stiffness also constitutes an important independent factor that can determine risk of cardiovascular events in patients with RH; it is an important indicator of vascular changes, and is associated with cardiovascular mortality. Arterial stiffness can be assessed by 3 measures: central blood pressure, augmentation index (AIx) and pulse wave velocity (PWV). PWV is a recognized as main marker of the severity of vascular injury. The increase in central blood pressure caused by backward (reflected) waves can be evaluated as an index derived from an analysis of the central aortic blood pressure curve known as the AIx, and depends on the magnitude and time of the reflected waves and indirectly on heart frequency and arterial stiffness. The evaluation of patients with RH is focused on the identification of causes of hypertension guided by the clinical features of hypertension and metabolic, vascular, endocrine and family history.

Inflamação, disfunção endotelial e eventos agudos na hipertensão arterial / Inflammation, endothelial dysfunction and acute events in hypertension

A inflamação tem sido reconhecida como importante fator no desenvolvimento da hipertensão arterial sistêmica e suas complicações agudas. Evidências indicam que a inflamação vascular possa estar envolvida tanto na gênese quanto na evolução da hipertensão arterial sistêmica, em conjunto com outros fatores bem estabelecidos. Alterações endoteliais causam inflamação localizada e lesões vasculares. A disfunção endotelial ocorre quando os efeitos vasoconstritores se sobrepõem aos efeitos vasodilatadores, sendo definida como uma alteração do relaxamento vascular dependente do endotélio. O endotélio detecta estímulos mecânicos (shear stress) e hormonais, e em resposta libera agentes vasomotores e inflamatórios, que afetam a homeostase vascular. O processo inflamatório pode prejudicar os mecanismos de reparação, como o recrutamento de células progenitoras endoteliais. Esses dados têm desencadeado estudos sobre vários marcadores inflamatórios e doenças cardiovasculares, reforçando a importância dos mecanismos de disfunção endotelial

Inflammation has been recognized as an important factor in the development of hypertension and of its acute complications. Evidences indicate that vascular inflammation may be involved in both the pathogenesis and the evolution of hypertension, together with other well-established factors. Endothelial changes cause localized inflammation and vascular injury. Endothelial dysfunction occurs when the vasoconstrictor effects outweigh the vasodilator effects, defined as an alteration of endothelium-dependent vascular relaxation. The endothelium detects mechanical (shear stress) and hormonal stimuli and releases vasomotor response and inflammatory agents that affect vascular homeostasis. The inflammatory process can damage repair mechanisms such as the recruitment of endothelial progenitor cell, which contribute to vascular repair. These data have triggered studies on various inflammatory markers and cardiovascular disease, reinforcing the importance of the endothelial dysfunction mechanisms and the participation of endothelium in this process.