Blood pressure at rest, during 24 h monitoring and in response to sympathetic stimulation in hypertensive patients with metabolic syndrome

Mechanical and metabolic reflex activation of the sympathetic nervous system in younger adults with metabolic syndrome

AIM

Based on reports of exaggerated blood pressure responses to whole-body exercise in patients with metabolic syndrome (MetSyn), we tested the hypothesis that MetSyn adults would exhibit augmented sympathetic and pressor responses to mechanoreflex and metaboreflex activation when compared with healthy, age-matched control subjects.

METHODS

We studied 12 adults with MetSyn (34±3years) and 12 healthy control subjects (34±3years). Heart rate (HR; ECG), blood pressure (BP; finger photoplethysmography), and MSNA (microneurography of the peroneal nerve) were measured during: (1) static handgrip exercise at 15% of maximal voluntary contraction (MVC), and (2) static handgrip exercise at 30% MVC to fatigue, followed by post-exercise ischemia (PEI). Increases in MSNA, HR, and BP were assessed.

RESULTS

During static exercise at both 15 and 30% MVC, increases in MSNA, HR, and BP were not different between groups. MSNA remained significantly elevated from baseline during PEI and responses were not different between groups.

CONCLUSION

Sympathetic and pressor responses to mechanoreflex and metaboreflex activation are not augmented in younger adults with MetSyn.

Cardiovascular reactivity and cardiometabolic risk in adolescents

BACKGROUND

Cardiovascular reactivity has been examined as a risk marker or factor in the pathogenesis of hypertension or cardiovascular disease, but few have examined the relationship with the metabolic syndrome.

PURPOSE

We examined whether cardiovascular reactivity to laboratory stress is associated with individual cardiometabolic risk factors and their co-occurrence. A significant positive relationship was hypothesized for both individual and clustered risk factors in their cross-sectional associations with reactivity to multiple stressors.

METHODS

A sample of 144, 15-17-year-old adolescents (74 % boys) largely from ethnic minority groups (54 % Hispanic White, 26 % Black) were identified at annual blood pressure (BP) screening (39 % with elevated BP) at high schools in Miami, Florida, USA. Participants completed the evaluated speaking, mirror star tracing, and cold pressor tasks, as well as cardiometabolic risk factor blood sampling. Participants were classified into metabolic syndrome criterion groups (0, 1, 2, or ≥3 criteria) based on American Heart Association adult criteria.

RESULTS

Multiple regression analyses with individual metabolic syndrome variables demonstrated that diastolic (D)BP reactivity during the mirror star tracing task accounted for 1.3 %, 3.8 %, and 5.1 % of the respective variances in casual systolic BP, waist circumference, and triglycerides (ps < 0.05). In multinomial logistic regression models, increased DBP reactivity during mirror star tracing and cold pressor tasks, and decreased HR reactivity during the cold pressor, were associated with greater likelihood of risk factor co-occurrence (ranging from 8.3 % to 15.8 %).

CONCLUSIONS

Findings indicate that autonomic reactivity to the mirror star tracing and cold pressor tasks, but not the evaluated speaking task, is associated with risk factor co-occurrence, and reactivity may be a clinical prognosticator of cardiometabolic disease risk.

Perceived discrimination and hypertension among African Americans in the Jackson Heart Study

OBJECTIVES

Using Jackson Heart Study data, we examined whether perceived discrimination was associated with prevalent hypertension in African Americans.

METHODS

Everyday discrimination, lifetime discrimination, burden of discrimination, and stress from discrimination were examined among 4939 participants aged 35 to 84 years (women = 3123; men = 1816). We estimated prevalence ratios of hypertension by discrimination, and adjusted for age, gender, socioeconomic status, and risk factors.

RESULTS

The prevalence of hypertension was 64.0% in women and 59.7% in men. After adjustment for age, gender, and socioeconomic status, lifetime discrimination and burden of discrimination were associated with greater hypertension prevalence (prevalence ratios for highest vs lowest quartile were 1.08 [95% confidence interval (CI) = 1.02, 1.15] and 1.09 [95% CI = 1.02,1.16] for lifetime discrimination and burden of discrimination, respectively). Associations were slightly weakened after adjustment for body mass index and behavioral factors. No associations were observed for everyday discrimination.

CONCLUSIONS

Further understanding the role of perceived discrimination in the etiology of hypertension may be beneficial in eliminating hypertension disparities.

Metabolic syndrome and exaggerated blood pressure response to exercise in newly diagnosed hypertensive patients

Background: Running evidence supports a prognostic value of an exaggerated blood pressure response to exercise (EBPR). The impact of the metabolic syndrome (MS) on EBPR in hypertensive patients has not been investigated.

Design: A cross-sectional study in the setting of an outpatient hypertension clinic.

Methods: In total, 325 non-diabetic patients with newly diagnosed hypertension were divided into two groups based on the presence ( n = 95) or absence ( n = 230) of the MS as defined with NCEP-ATP III criteria. All subjects underwent ambulatory blood pressure monitoring, echocardiography and exercise treadmill testing.

Results: Hypertensive patients with MS exhibited higher prevalence of EBPR (by 17%, p = 0.002) and peak exercise systolic BP (by 10.4 mmHg, p = 0.001) irrespectively of confounders. Metabolic equivalents were higher in hypertensives with MS (by 0.6 ml/kg/min, p = 0.048), but the difference lost significance after adjusting for confounders, including body mass index. Logistic regression analysis identified the MS as an independent predictor of an EBPR ( p = 0.016). Hypertensive patients with MS had a 2.3-fold risk of exhibiting EBPR compared to those without MS. However, individual components of MS altogether as well as each one separately failed to predict EBPR.

Conclusions: Presence of MS in newly diagnosed hypertensive patients is associated with increased peak exercise BP and a higher frequency of EBPR over and above its separate elements.

Ambulatory blood pressure monitoring in type 2 diabetes and metabolic syndrome: a review

We reviewed the literature on ambulatory blood pressure (BP) monitoring in type 2 diabetes mellitus (T2DM) (focusing on organ damage progression, prognosis, white coat hypertension, and masked hypertension) and metabolic syndrome (MetS). In the text we reported 21 articles about T2DM and 11 about MetS, part of which were included in meta-analyses. In T2DM, individual studies and meta-analyses indicate that 24-h pulse pressure and reduced night-time BP fall or reverse dipping predict organ damage progression, total cardiovascular events and all-cause mortality. Moreover, white coat hypertension seems to be less frequent in T2DM and its impact on cardiovascular complications remains controversial. In contrast, masked hypertension is more frequent in T2DM and seems to be associated with increased organ damage. Some studies reported higher ambulatory BP in patients with MetS, but these patients were older and had higher clinical BP than those without MetS. With regard to the circadian BP profile, contrasting data have been reported, although pooled data suggest a higher risk of nondipping in patients with MetS.

Perturbed autonomic nervous system function in metabolic syndrome

The metabolic syndrome is characterized by the clustering of various common metabolic abnormalities in an individual and it is associated with increased risk for the development of type 2 diabetes and cardiovascular diseases. Its prevalence in the general population is approximately 25%. Central fat accumulation and insulin resistance are considered as the common denominators of the abnormalities of the metabolic syndrome. Subjects with metabolic syndrome have autonomic nervous system dysfunction characterized by predominance of the sympathetic nervous system in many organs, i.e. heart, kidneys, vasculature, adipose tissue, and muscles. Sympathetic nervous system activation in metabolic syndrome is detected as increased heart rate and blood pressure, diminished heart rate variability, baroreceptor dysfunction, enhanced lipolysis in visceral fat, increased muscle sympathetic nerve activity, and high urine or plasma catecholamine concentrations as well as turnover rates. The augmented sympathetic activity in individuals with metabolic syndrome worsens prognosis of this high-risk population. The mechanisms linking metabolic syndrome with sympathetic activation are complex and not clearly understood. Whether sympathetic overactivity is involved in the development of the metabolic syndrome or is a consequence of it remains to be elucidated since data from prospective studies are missing. Intervention studies have demonstrated that the autonomic disturbances of the metabolic syndrome may be reversible.