Secondary hypertension: obesity and the metabolic syndrome

High-output Cardiac Failure: A Forgotten Phenotype in Clinical Practice

INTRODUCTION

The knowledge on High-Output Cardiac Failure (HOCF) has greatly improved in the last two decades. One of the advances was the identification of a new phenotype of HOCF, characterized by the absence of ventricular dilation, already associated with liver disease, Arteriovenous Fistulas (AVF), lung disease, myelodysplastic syndromes, and obesity. However, it has been noted that any aetiology can present with one of the two phenotypes, depending on the evolution.

OBJECTIVE

The study aims to describe, through an integrative review, the physiopathology and aetiologies of HOCF and to discuss phenotypes associated with this condition.

METHODS

Revisions, guidelines, case-controls, cohort studies and clinical studies were searched in MEDLINE and LILACS, using the connectives in the "cardiac output, high" database (MeSH Terms) OR "high cardiac output" (All Fields).

DISCUSSION

Two distinct phenotypes are currently described in the HOCF, regardless of the aetiology: 1) one with enlarged cardiac chambers; and 2) with normal heart chambers. The mechanisms related to HOCF are vasodilation, arteriovenous shunts that cause increased microvascular density, Reduced Systemic Vascular Resistance (RSVR), and high metabolism. These mechanisms lead to activation of the renin-angiotensin-aldosterone system, sodium and water retention, activation of neprilysin, of the sodium-glucose-2 transporter, which promote interstitial fibrosis, ventricular remodeling and a consequent increase in cardiac output >8L/min.

CONCLUSION

Many aetiologies of HOCF have been described, and some of them are potentially curable. Prompt recognition of this condition and proper treatment may lead to better outcomes.

Non-coding RNAs and the mineralocorticoid receptor in the kidney

The final steps in the Renin-Angiotensin-Aldosterone signaling System (RAAS) involve binding of the corticosteroid hormone, aldosterone to its mineralocorticoid receptor (MR). The bound MR interacts with response elements to induce or repress the transcription of aldosterone-regulated genes. Along with the classic genomic targets of aldosterone that alter mRNA and protein expression, aldosterone also regulates the expression of non-coding RNAs (ncRNAs). Short ncRNAs termed microRNAs (miRs) have been shown to play a role in transducing aldosterone's actions via MR signaling. The role of miRs in homeostatic regulation of aldosterone signaling, and the potential for aldosterone-regulated miRs to act as feedback regulators of MR have been recently reported. In this review, the role of miRs in RAAS signaling and feedback regulation of MR in kidney epithelial cells will be discussed.

Characteristics and resolution of hypertension in obese African American bariatric cohort

Weight reduction continues to be first-line therapy in the treatment of hypertension (HTN). However, the long-term effect of bariatric malabsorptive surgical techniques such as Roux-en-Y Gastric Bypass (RYGB) surgery in the management of hypertension (HTN) is less clear. African Americans (AA) are disproportionately affected by obesity and hypertension and have inconsistent outcomes after bariatric surgery (BS). Despite a plethora of bariatric literature, data about characteristics of a predominantly AA bariatric hypertensive cohort including hypertension in obese (HIO) are scarce and underreported. The aims of this study were, (1) to describe the preoperative clinical characteristics of HIO with respect to HTN status and age, and (2) to identify predictors of HTN resolution one year after RYGB surgery in an AA bariatric cohort enrolled at the Howard University Center for Wellness and Weight Loss Surgery (HUCWWS). In the review of 169 AA bariatric patients, the average BMI was 48.50 kg/m2 and the average age was 43.86 years. Obese hypertensive patients were older (46 years vs. 37.89 years; p < .0001); had higher prevalence of diabetes mellitus (DM, 43.09% vs. 10.87%; p < .0001) and dyslipidemia (38.2% vs. 13.04%; p 0.002). Hypertensive AA who were taking ≥ 2 antihypertensive medications prior to RYGB were 18 times less likely to experience HTN resolution compared to hypertensive AA taking 0-1 medications, who showed full or partial response. Also, HIO was less likely to resolve after RYGB surgery in patients who needed ≥ 2 antihypertensive medications prior to surgical intervention.

Characteristics and resolution of hypertension in obese African American bariatric cohort

Weight reduction continues to be first-line therapy in the treatment of hypertension (HTN). However, the long-term effect of bariatric malabsorptive surgical techniques such as Roux-en-Y Gastric Bypass (RYGB) surgery in the management of hypertension (HTN) is less clear. African Americans (AA) are disproportionately affected by obesity and hypertension and have inconsistent outcomes after bariatric surgery (BS). Despite a plethora of bariatric literature, data about characteristics of a predominantly AA bariatric hypertensive cohort including hypertension in obese (HIO) are scarce and underreported. The aims of this study were, (1) to describe the preoperative clinical characteristics of HIO with respect to HTN status and age, and (2) to identify predictors of HTN resolution one year after RYGB surgery in an AA bariatric cohort enrolled at the Howard University Center for Wellness and Weight Loss Surgery (HUCWWS). In the review of 169 AA bariatric patients, the average BMI was 48.50 kg/m2 and the average age was 43.86 years. Obese hypertensive patients were older (46 years vs. 37.89 years; p < .0001); had higher prevalence of diabetes mellitus (DM, 43.09% vs. 10.87%; p < .0001) and dyslipidemia (38.2% vs. 13.04%; p 0.002). Hypertensive AA who were taking ≥ 2 antihypertensive medications prior to RYGB were 18 times less likely to experience HTN resolution compared to hypertensive AA taking 0-1 medications, who showed full or partial response. Also, HIO was less likely to resolve after RYGB surgery in patients who needed ≥ 2 antihypertensive medications prior to surgical intervention.

Effect of Obesity on Pulmonary Vascular Hemodynamics

CONTEXT

Obesity-related pulmonary arterial hypertension (PAH) is associated with hypoxia and metabolic abnormalities. Although right heart catheterization is the gold standard method for the diagnosis of PAH, Doppler echocardiography is more common. On the other hand, there is no definite echocardiographic parameter for PAH diagnosis. Novel echocardiographic parameter, pulmonary pulse transit time (pPTT), is assumed to be a surrogate marker for the assessment of PAH.

AIMS

The aim was to evaluate whether pPTT might be valuable for evaluating pulmonary vascular hemodynamics in obese patients.

SETTINGS AND DESIGN

A cross-sectional observational study.

METHODS

A total of 130 consecutive obese patients and 50 controls were included. Obese patients were divided into three groups according to body mass index (BMI): 25 < BMI <30 kg/m2 formed Group 1, 30 < BMI <35 kg/m2 formed Group 2, and 35

STATISTICAL ANALYSIS USED

Intergroup differences were analyzed with analysis of variance or Kruskal-Wallis test. Pearson's or Spearman's correlation analysis was used for correlation, multivariate logistic regression analysis, and regression.

RESULTS

Statistically significant reduction in pPTT was detected as early as in the first group (361.24 ± 25.54 vs. 391.26 ± 15.07; P = 0.015) and continued throughout Groups 2 and 3 (299.92 ± 35.10 vs. 391.26 ± 15.07; P < 0.0001, and 245.46 ± 11.25 vs. 391.26 ± 15.07; P < 0.0001, respectively). There was a strong negative correlation between pPTT and BMI (r = -0.848, P = 0.001). On linear regression analysis, BMI was found to be an independent risk factor for pPTT (confidence interval: -9.164-6.379, β = -0.525, P = 0.0001).

CONCLUSION

The results of this study suggest that obesity leads to an increase in PAH, and pPTT allows noninvasive determination of the pulmonary hemodynamics in obese patients. pPTT might be a useful parameter in terms of predicting pulmonary hemodynamics and vascular alterations in obese patients. Further studies are warranted to evaluate the association between obesity and PAH.

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Key Words

• Obesity
• pulmonary pulse transit time
• pulmonary vascular hemodynamics

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Affiliation(s)

Mustafa Duran Department of Cardiology, Konya Education and Research Hospital, Konya, Turkey
Murat Ziyrek Department of Cardiology, Konya Education and Research Hospital, Konya, Turkey

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Effectiveness of Valsartan/Amlodipine Single-pill Combination in Hypertensive Patients With Excess Body Weight: Subanalysis of China Status II

Obesity is a major global health concern and is associated with hypertension. However, there is a lack of studies evaluating the effectiveness of valsartan/amlodipine single-pill combination in Chinese hypertensive patients with excess body weight uncontrolled by monotherapy. To evaluate this effectiveness and its association with obese categories, we performed a prespecified subanalysis and a post hoc analysis of patients from China status II study. In this subanalysis, 11,289 and 11,182 patients stratified by body mass index (BMI) and waist circumference (WC), respectively, were included. Significant mean sitting systolic and diastolic blood pressure (BP) reductions from baseline were observed at week 8 across all BMI and WC subgroups (P < 0.001). The percentages of patients achieving BP control were 65.2%, 62.8%, and 64.5% (men 64.5% and women 64.4%) in the overweight, obesity, and abdominal obesity subgroups, respectively. The positive association between BP control and obese categories could only be found in subgroups stratified by BMI other than WC. Our study demonstrated the effectiveness of valsartan/amlodipine single-pill combination in Chinese hypertensive patients with excess body weight uncontrolled by monotherapy, and its effectiveness was better associated with BMI than WC.

A combined continuous and interval aerobic training improves metabolic syndrome risk factors in men

Individuals with metabolic syndrome have significantly higher risk of cardiovascular disease and type 2 diabetes leading to premature death mortality. Metabolic syndrome has a complex etiology; thus, it may require a combined and multi-targeted aerobic exercise regimen to improve risk factors associated with it. Therefore, the aim of this study was to evaluate the effect of combined continuous and interval aerobic training on patients with metabolic syndrome. Thirty adult male with metabolic syndrome (54±8 years) were randomly divided into two groups: test training group (TTG; n=15) and control group (CG; n=15). Subjects in TTG performed combined continuous and interval aerobic training using a motorized treadmill three times per week for 16 weeks. Subjects in CG were advised to continue with their normal activities of life. Twenty-two men completed the study (eleven men in each group). At the end of the study, in TTG, there were significant (for all, P<0.05) reductions in total body weight (−3.2%), waist circumference (−3.43 cm), blood pressure (up to −12.7 mmHg), and plasma insulin, glucose, and triacylglyceride levels. Moreover, there were significant (for all, P<0.05) increases VO₂max (−15.3%) and isometric strength of thigh muscle (28.1%) and high-density lipoprotein in TTG. None of the above indices were changed in CG at the end of 16-week study period. Our study suggests that adoption of a 16-week combined continuous and interval aerobic training regimen in men with metabolic syndrome could significantly reduce cardiovascular risk factors in these patients.

Network-based analysis of the sphingolipid metabolism in hypertension

Common diseases like essential hypertension or diabetes mellitus are complex as they are polygenic in nature, such that each genetic variation only has a small influence on the disease. Genes operates in integrated networks providing the blue-print for all biological processes and conditional of the complex genotype determines the state and dynamics of any trait, which may be modified to various extent by non-genetic factors. Thus, diseases are heterogenous ensembles of conditions with a common endpoint. Numerous studies have been performed to define genes of importance for a trait or disease, but only a few genes with small effect have been identified. The major reasons for this modest progress is the unresolved heterogeneity of the regulation of blood pressure and the shortcomings of the prevailing monogenic approach to capture genetic effects in a polygenic condition. Here, a two-step procedure is presented in which physiological heterogeneity is disentangled and genetic effects are analyzed by variance decomposition of genetic interactions and by an information theoretical approach including 162 single nucleotide polymorphisms (SNP) in 84 genes in the sphingolipid metabolism and related networks in blood pressure regulation. As expected, almost no genetic main effects were detected. In contrast, two-gene interactions established the entire sphingolipid metabolic and related genetic network to be highly involved in the regulation of blood pressure. The pattern of interaction clearly revealed that epistasis does not necessarily reflects the topology of the metabolic pathways i.e., the flow of metabolites. Rather, the enzymes and proteins are integrated in complex cellular substructures where communication flows between the components of the networks, which may be composite in structure. The heritabilities for diastolic and systolic blood pressure were estimated to be 0.63 and 0.01, which may in fact be the maximum heritabilities of these traits. This procedure provide a platform for studying and capturing the genetic networks of any polygenic trait, condition, or disease.

Real-world effectiveness of amlodipine/valsartan and amlodipine/valsartan/hydrochlorothiazide in high-risk patients and other subgroups

Background

The clinical EXCITE (EXperienCe of amlodIpine and valsarTan in hypErtension) study reported clinically relevant blood pressure (BP) reductions across all doses of amlodipine/valsartan (Aml/Val) and Aml/Val/hydrochlorothiazide (HCT) single-pill combinations. The study prospectively observed a multiethnic population of hypertensive patients for 26 weeks who were treated according to routine clinical practice. Here, we present the results in high-risk subgroups including the elderly, obese patients, and patients with diabetes or isolated systolic hypertension. In addition, we present a post hoc analysis as per prior antihypertensive monotherapy and dual therapy.

Methods

Patients prescribed Aml/Val or Aml/Val/HCT were assessed in this 26±8 week, noninterventional, multicenter study across 13 countries in the Middle East and Asia. Changes in mean sitting systolic BP, mean sitting diastolic BP, and overall safety were assessed.

Results

Of a total of 9,794 patients analyzed, 8,603 and 1,191 patients were prescribed Aml/Val and Aml/Val/HCT, respectively. Among these, 15.5% were elderly, 32.5% were obese, 31.3% had diabetes, and 9.8% had isolated systolic hypertension. Both Aml/Val and Aml/Val/HCT single-pill combinations, respectively, were associated with clinically relevant and significant mean sitting systolic/diastolic BP reductions across all subgroups: elderly patients (−32.2/−14.3 mmHg and −38.5/−16.5 mmHg), obese patients (−32.2/−17.9 mmHg and −38.5/−18.4 mmHg), diabetic patients (−30.3/−16.1 mmHg and −34.4/−16.6 mmHg), and patients with isolated systolic hypertension (−25.5/−4.1 mmHg and −30.2/−5.9 mmHg). Incremental BP reductions with Aml/Val or Aml/Val/HCT single-pill combinations were also observed in patients receiving prior monotherapy or dual therapy for hypertension. Overall, both Aml/Val and Aml/Val/HCT were generally well tolerated.

Conclusion

This large, multiethnic study supports the evidence that Aml/Val and Aml/Val/ HCT single-pill combinations are effective in diverse and clinically important subgroups of patients with hypertension.

Obesity-related pulmonary arterial hypertension in rats correlates with increased circulating inflammatory cytokines and lipids and with oxidant damage in the arterial wall but not with hypoxia

Obesity is causally linked to a number of comorbidities, including cardiovascular disease, diabetes, renal dysfunction, and cancer. Obesity has also been linked to pulmonary disorders, including pulmonary arterial hypertension (PAH). It was long believed that obesity-related PAH was the result of hypoventilation and hypoxia due to the increased mechanical load of excess body fat. However, in recent years it has been proposed that the metabolic and inflammatory disturbances of obesity may also play a role in the development of PAH. To determine whether PAH develops in obese rats in the absence of hypoxia, we assessed pulmonary hemodynamics and pulmonary artery (PA) structure in the diet-resistant/diet-induced obesity (DR/DIO) and Zucker lean/fatty rat models. We found that high-fat feeding (DR/DIO) or overfeeding (Zucker) elicited PA remodeling, neomuscularization of distal arterioles, and elevated PA pressure, accompanied by right ventricular (RV) hypertrophy. PA thickening and distal neomuscularization were also observed in DIO rats on a low-fat diet. No evidence of hypoventilation or chronic hypoxia was detected in either model, nor was there a correlation between blood glucose or insulin levels and PAH. However, circulating inflammatory cytokine levels were increased with high-fat feeding or calorie overload, and hyperlipidemia and oxidant damage in the PA wall correlated with PAH in the DR/DIO model. We conclude that hyperlipidemia and peripheral inflammation correlate with the development of PAH in obese subjects. Obesity-related inflammation may predispose to PAH even in the absence of hypoxia.

The association between calcium channel blocker use and prostate cancer outcome

BACKGROUND

Epidemiological studies indicate that calcium channel blocker (CCB) use is inversely related to prostate cancer (PCa) incidence. The association between CCB use and PCa aggressiveness at the time of radical prostatectomy (RP) and outcome after RP was examined.

METHODS

Medication use, PCa aggressiveness and post-RP outcome were retrieved from a prospectively populated database that contains clinical and outcome for RP patients at Roswell Park Cancer Institute (RPCI) from 1993 to 2010. The database was queried for anti-hypertensive medication use at diagnosis for patients with ≥1 year follow-up. Recurrence was defined using NCCN guidelines. Chi-Square tests assessed the relationship between CCB use and PCa aggressiveness. Cox regression models compared the distribution of progression-free survival (PFS) and overall survival (OS) with adjustment for covariates. Results for association between CCB usage and PCa aggressiveness were validated using data from the population-based North Carolina-Louisiana Prostate Cancer Project (PCaP).

RESULTS

48%, 37%, and 15% of RPCI's RP patients (n = 875) had low, intermediate, and high aggressive PCa, respectively. 104 (11%) had a history of CCB use. Patients taking CCBs were more likely to be older, have a higher BMI and use additional anti-hypertensive medications. Diagnostic PSA levels, PCa aggressiveness, and margin status were similar for CCB users and non-users. PFS and OS did not differ between the two groups. Tumor aggressiveness was associated with PFS. CCB use in the PCaP study population was not associated with PCa aggressiveness.

CONCLUSIONS

CCB use is not associated with PCa aggressiveness at diagnosis, PFS or OS.

Treatment of hypertension in obese patients

Obesity is a global pandemic and with its rise, its associated co-morbidities are increasing in prevalence, particularly uncontrolled hypertension. Lifestyle changes should be an anchor for the management of obesity-related hypertension; however, they are difficult to sustain. Drug therapy is often necessary to achieve blood pressure control. Diuretics, inhibitors of the renin-angiotensin system, and dihydropyridine calcium channel blockers are often used as first trio, with subsequent additions of mineralocorticoid receptor antagonists and/or dual alpha/beta blocking agents. While a number of agents are currently available, 50 % of hypertensive patients remain uncontrolled. A number of novel drug and invasive therapies are in development and hold significant potential for the effective management of obesity-related hypertension.

Genetics of the ceramide/sphingosine-1-phosphate rheostat in blood pressure regulation and hypertension

BACKGROUND

Several attempts to decipher the genetics of hypertension of unknown causes have been made including large-scale genome-wide association analysis (GWA), but only a few genes have been identified. Unsolved heterogeneity of the regulation of blood pressure and the shortcomings of the prevailing monogenic approach to capture genetic effects in a polygenic condition are the main reasons for the modest results. The level of the blood pressure is the consequence of the genotypic state of the presumably vast network of genes involved in regulating the vascular tonus and hence the blood pressure. Recently it has been suggested that components of the sphingolipid metabolism pathways may be of importance in vascular physiology. The basic metabolic network of sphingolipids has been established, but the influence of genetic variations on the blood pressure is not known. In the approach presented here the impact of genetic variations in the sphingolipid metabolism is elucidated by a two-step procedure. First, the physiological heterogeneity of the blood pressure is resolved by a latent class/structural equation modelling to obtain homogenous subpopulations. Second, the genetic effects of the sphingolipid metabolism with focus on de novo synthesis of ceramide are analysed. The model does not assume a particular genetic model, but assumes that genes operate in networks.

RESULTS

The stratification of the study population revealed that (at least) 14 distinct subpopulations are present with different propensity to develop hypertension. Main effects of genes in the de novo synthesis of ceramides were rare (0.14% of all possible). However, epistasis was highly significant and prevalent amounting to approximately 70% of all possible two-gene interactions. The phenotypic variance explained by the ceramide synthesis network were substantial in 4 of the subpopulations amounting to more than 50% in the subpopulation in which all subjects were hypertensive. Construction of the network using the epistatic values revealed that only 17% of the interactions detected were in the direct metabolic pathway, the remaining jumping one or more intermediates.

CONCLUSIONS

This study established the components of the ceramide/sphingosine-1-phosphate rheostat as central to blood pressure regulation. The results in addition confirm that epistasis is of paramount importance and is most conspicuous in the regulation of the rheostat network. Finally, it is shown that applying a simple case-control approach with single gene association analysis is bound to fail, short of identifying a few potential genes with small effects.

BMI and lifestyle changes as correlates to changes in self-reported diagnosis of hypertension among older Chinese adults

Nutrition transition theory attributes increased prevalence of high blood pressure to excess body weight associated with lifestyle changes in recent decades. We examined the association of changes in self-reported hypertension diagnoses with changes in body mass index (BMI), health-related behaviors, health status, and social risk factors among older Chinese adults from 1997 to 2006. Data from the longitudinal China Health and Nutrition Survey (CHNS) were analyzed for adults who were age 60 years and older, had a BMI exceeding 18.6 kg/m(2), and reported no diagnosis of hypertension at baseline (n = 1928). Logistic regression models identified factors contributing to staying nonhypertensive or developing hypertension over time. Approximately 17.8% (n = 324) of study participants developed self-reported hypertension, whereas 83.2% (n = 1604) remained without hypertension. Those who stayed overweight or obese or became overweight or obese were more likely to report a new hypertension diagnosis. Incident diagnoses were also observed among those who developed acute conditions, sustained memory loss, or increased their income, whereas remaining nonhypertensive was more likely among rural residents and those who became more physically active and quit drinking alcohol. Study findings provided partial support for the nutrition transition theory whereby changing demographics and lifestyle factors were associated with increases in incident hypertension.

Traffic-related air pollution and blood pressure in elderly subjects with coronary artery disease

BACKGROUND

Associations between blood pressure (BP) and ambient air pollution have been inconsistent. No studies have used ambulatory BP monitoring and outdoor home air-pollutant measurements with time-activity-location data. We address these gaps in a study of 64 elderly subjects with coronary artery disease, living in retirement communities in the Los Angeles basin.

METHODS

Subjects were followed up for 10 days with hourly waking ambulatory BP monitoring (n = 6539 total measurements), hourly electronic diaries for perceived exertion and location, and real-time activity monitors (actigraphs). We measured hourly outdoor home pollutant gases, particle number, PM2.5, organic carbon, and black carbon. Data were analyzed with mixed models controlling for temperature, posture, actigraph activity, hour, community, and season.

RESULTS

We found positive associations of systolic and diastolic BP with air pollutants. The strongest associations were with organic carbon (especially its estimated fossil-fuel- combustion fraction), multiday average exposures, and time periods when subjects were at home. An interquartile increase in 5-day average organic carbon (5.2 microg/m) was associated with 8.2 mm Hg higher mean systolic BP (95% confidence interval = 3.0-13.4) and 5.8 mm Hg higher mean diastolic BP (3.0-8.6). Associations of BP with 1-8 hour average air pollution were stronger with reports of moderate to strenuous physical exertion but not with higher actigraph motion. Associations were also stronger among 12 obese subjects.

CONCLUSIONS

Exposure to primary organic components of fossil fuel combustion near the home were strongly associated with increased ambulatory BP in a population at potential risk of heart attack. Low fitness or obesity may increase the effects of pollutants.

Mitochondrial dysfunction and metabolic syndrome-looking for environmental factors

The centerpiece of the pathophysiologic mechanism of metabolic syndrome is insulin resistance. Recently, it is becoming evident that mitochondrial dysfunction is closely related to insulin resistance and metabolic syndrome. The underlying mechanism of mitochondrial dysfunction is very complex, which includes genetic factors from both nuclear and mitochondrial genome and numerous environmental factors. Several mitochondrial DNA polymorphisms are associated with the components of metabolic syndrome. Numerous chemicals and drugs may cause mitochondrial dysfunction and insulin resistance. Notably, it was recently reported that serum levels of several mitochondrial toxins, such as persistent organic pollutants are associated with metabolic syndrome, which necessitates further investigation to reveal its precise mechanism. Given that the health impact of metabolic syndrome is tremendous, it is necessary to develop therapeutic modalities to correct mitochondrial dysfunction or at least to halt its aggravation. In this regard, exercise can improve both mitochondrial function and insulin sensitivity, and some pharmaceutical agents were reported to improve mitochondrial function. However, further studies are warranted to find more effective therapeutic strategies to treat mitochondrial dysfunction. By doing so, we can also shed light on the path of research for other diseases related to mitochondrial dysfunction.