C-reactive protein as a predictor of hypertension in the Hong Kong Cardiovascular Risk Factor Prevalence Study (CRISPS) cohort

Recent Advances in Understanding Peripheral and Gut Immune Cell-Mediated Salt-Sensitive Hypertension and Nephropathy

Hypertension is the primary modifiable risk factor for cardiovascular, renal, and cerebrovascular diseases and is considered the main contributing factor to morbidity and mortality worldwide. Approximately 50% of hypertensive and 25% of normotensive people exhibit salt sensitivity of blood pressure, which is an independent risk factor for cardiovascular disease. Human and animal studies demonstrate that the immune system plays an important role in the etiology and pathogenesis of salt sensitivity of blood pressure, kidney damage, and vascular diseases. Antigen-presenting and adaptive immune cells are implicated in salt-sensitive hypertension and salt-induced renal and vascular injury. Elevated sodium activates antigen-presenting cells to release proinflammatory cytokines including IL (interleukin) 6, tumor necrosis factor-α, IL-1β, and accumulate isolevuglandin-protein adducts. In turn, these activate T cells release prohypertensive cytokines including IL-17A. Moreover, high-salt intake is associated with gut dysbiosis, leading to inflammation, oxidative stress, and blood pressure elevation but the mechanistic contribution to salt-sensitivity of blood pressure is not clearly understood. Here, we discuss recent advances in research investigating the cause, potential biomarkers, and therapeutic targets for salt-sensitive hypertension as they pertain to the gut microbiome, immunity, and inflammation.

The effect of nonrestorative sleep on incident hypertension 1-2 years later among middle-aged Hispanics/Latinos

BACKGROUND

Insomnia is known to be a major risk factor for incident hypertension. Nonrestorative sleep (NRS), which refers to insufficiently rested sleep, has reported to associate with various diseases. This study aimed to investigate the longitudinal association between insomnia-related symptoms including NRS and incident hypertension 1-2 years later by age group (young, 18-39 years and middle-age, 40-64 years) using existing cohort data involving Hispanics/Latinos.

METHODS

This study included 1100 subjects who had participated in both the Hispanic Community Health Study/Study of Latinos and its follow-up study, the Sueño Ancillary Study, and met additional eligibility criteria. Incident hypertension was assessed by self-reported history and/or the use of antihypertensives. The Women's Health Initiative Insomnia Rating Scale (WHIIRS) was used to evaluate insomnia-related symptoms (difficulty initiating sleep, difficulty maintaining sleep, early morning awakening, difficulty returning to sleep, and NRS). Logistic regression analyses were conducted to assess the degree to which insomnia-related symptoms at baseline predicted incident hypertension.

RESULTS

Among the participants (64% middle-aged, 36% young adults), 140 (12.7%) developed hypertension during the follow-up period. Among the sleep-related symptoms, only NRS predicted incident hypertension after adjusting for sociodemographic factors and physical condition (odds ratio: 1.88, 95% confidence interval: 1.10-3.21, p = 0.022) in middle-aged adults. None of the insomnia-related symptoms were associated with incident hypertension in the young adults. No association was found between WHIIRS-defined insomnia (total score ≥ 9) and incident hypertension in middle-aged adults or young adults.

CONCLUSION

The present findings suggest the importance of focusing on NRS to help prevent the development of hypertension in middle-aged adults.

Inflammatory markers in patients with hypertension

Hypertension is a chronic disease with high levels of morbidity and disability. Elevated blood pressure can lead to many complications and is the main risk factor for stroke, heart failure and nephropathy. Factors associated with hypertension and inflammatory response differ from those associated with vascular inflammation. The immune system plays a vital role in the pathophysiology of hypertension. Inflammation is particularly relevant in the progression of cardiovascular diseases, which has led to extensive research on inflammatory markers and indicators.

Very low-calorie ketogenic diet (VLCKD): an antihypertensive nutritional approach

BACKGROUND

Obesity is accompanied by hormonal, inflammatory and endothelial alterations. These alterations induce a stimulation of several other mechanisms that contribute to the hypertensive state and to increase the cardiovascular morbidity. This pilot, open - label, single- center, prospective clinical trial aimed to evaluate the effect of very low- calorie ketogenic diet (VLCKD) on blood pressure (BP) in women with of obesity and hypertension.

METHODS

A total of 137 women, who met the inclusion criteria and accepted to adhere to VLCKD, were consecutively enrolled. Assessment of anthropometric parameters (weight, height, and waist circumference), body composition (through bioelectrical impedance analysis), systolic (SBP) and diastolic blood pressure (DBP) and blood sample collection were carried out at baseline and after 45 days of the active phase of VLCKD.

RESULTS

After VLCKD all the women experienced a significant reduction in body weight and an overall improvement of body composition parameters. In addition, high sensitivity C reactive protein (hs- CRP) levels were significantly diminished (p < 0.001), while phase angle (PhA) increased by almost 9% (p < 0.001). Interestingly, both SBP and DBP were significantly improved (-12.89% and - 10.77%, respectively; p < 0.001). At baseline, SBP and DBP showed statistically significant correlations with body mass index (BMI), waist circumference, hs-CRP levels, PhA, total body water (TBW), extracellular water (ECW), Na / K ratio, and fat mass. Even after VLCKD, all correlations among SBP and DBP with the study variables were statistically significant, except for the association between DBP and Na / K ratio. Changes (%) in both SBP and DBP were associated with ∆BMI%, ∆PhA% and ∆hs- CRP levels (p < 0.001). In addition, only ∆SBP% was associated with ∆waist circumference (p = 0.017), ∆TBW (p = 0.017), and ∆fat mass (p < 0.001); while only ∆DBP% was associated with ∆ECW (p = 0.018), and ∆Na / K ratio (p = 0.048). After adjusting for ∆BMI, ∆WC, ∆PhA, ∆TBW, and ∆fat mass, the correlation between changes in ∆SBP and ∆hs -CRP levels remained statistically significant (p < 0.001). Similarly, the correlation between ∆DBP and ∆hs- CRP levels also remained statistically significant after adjustment for ∆BMI, ∆PhA, ∆Na / K ratio, and ∆ECW (p < 0.001). From multiple regression analysis ∆hs- CRP levels seemed to be the main predictor of changes of BP (p < 0.001).

CONCLUSION

VLCKD reduces BP in women with of obesity and hypertension in a safely manner.

Inflammation and oxidative stress in salt sensitive hypertension; The role of the NLRP3 inflammasome

Salt-sensitivity of blood pressure is an independent risk factor for cardiovascular disease and affects approximately half of the hypertensive population. While the precise mechanisms of salt-sensitivity remain unclear, recent findings on body sodium homeostasis and salt-induced immune cell activation provide new insights into the relationship between high salt intake, inflammation, and hypertension. The immune system, specifically antigen-presenting cells (APCs) and T cells, are directly implicated in salt-induced renal and vascular injury and hypertension. Emerging evidence suggests that oxidative stress and activation of the NLRP3 inflammasome drive high sodium-mediated activation of APCs and T cells and contribute to the development of renal and vascular inflammation and hypertension. In this review, we summarize the recent insights into our understanding of the mechanisms of salt-sensitive hypertension and discuss the role of inflammasome activation as a potential therapeutic target.

Association of hypertension with infection and inflammation in a setting of disadvantage in rural India

We assessed the association of hypertension with markers of inflammation and infection in a rural and disadvantaged Indian population. In a case-control study, we age- and gender-matched 300 cases with hypertension to 300 controls without hypertension. Blood pressure was measured according to a strict protocol. We measured markers of inflammation and infection including serum high-sensitivity C-reactive protein (hs-CRP), blood lymphocyte count, serum homocysteine, tooth loss, overcrowding and exposure to fecal contamination. Multivariable conditional logistic regression was used to determine their association with hypertension. Median serum hs-CRP was 42% greater in cases than controls, while median serum homocysteine was 10% greater. In multivariable conditional logistic regression, elevated homocysteine (OR 1.75, 95% CI 1.09-2.82), greater lymphocyte count (OR 1.49, 95% CI 1.01-2.01) and exposure to fecal contamination, defined as a distance from the field used for toilet purposes to the household of ≤50 m (OR 2.38, 95% CI 1.07-5.29), were independently associated with hypertension in this rural population. In separate analyses for each gender, elevated hs-CRP (OR 2.62, 95% CI 1.04-6.58) was associated with hypertension in men, whereas edentulism (OR 4.75, 95% CI 1.62-13.96) was associated with greater odds of hypertension in women. Our findings demonstrate specific associations between hypertension and markers of inflammation and infection including hs-CRP, homocysteine, lymphocyte count, edentulism and exposure to fecal contamination. Thus, strategies aimed at reducing inflammation and infection may reduce the burden of hypertension in such settings of disadvantage in rural India.

Dendritic Cell Epithelial Sodium Channel in Inflammation, Salt-Sensitive Hypertension, and Kidney Damage

Salt-sensitive hypertension is a major risk factor for cardiovascular morbidity and mortality. The pathophysiologic mechanisms leading to different individual BP responses to changes in dietary salt remain elusive. Research in the last two decades revealed that the immune system plays a critical role in the development of hypertension and related end organ damage. Moreover, sodium accumulates nonosmotically in human tissue, including the skin and muscle, shifting the dogma on body sodium balance and its regulation. Emerging evidence suggests that high concentrations of extracellular sodium can directly trigger an inflammatory response in antigen-presenting cells (APCs), leading to hypertension and vascular and renal injury. Importantly, sodium entry into APCs is mediated by the epithelial sodium channel (ENaC). Although the role of the ENaC in renal regulation of sodium excretion and BP is well established, these new findings imply that the ENaC may also exert BP modulatory effects in extrarenal tissue through an immune-dependent pathway. In this review, we discuss the recent advances in our understanding of the pathophysiology of salt-sensitive hypertension with a particular focus on the roles of APCs and the extrarenal ENaC.

C-Reactive Protein Levels in relation to Incidence of Hypertension in Chinese Adults: Longitudinal Analyses from the China Health and Nutrition Survey

Objective

To explore the association between high sensitivity C-reactive protein (hs-CRP) levels and incident hypertension, as well as the association between hs-CRP levels and related covariates, in a Chinese adult population.

Methods

This study was based on the China Health and Nutrition Survey, a continuing open, large-scale prospective cohort study. Adult participants who were free of hypertension were included at baseline survey in 2009 and were followed up in 2015 (follow-up rate: 77.45%). The hs-CRP was measured using the immunoturbidimetric method and divided into three groups: low-risk group (0 ≤ hs-CRP <1 mg/L), average-risk group (1 ≤ hs-CRP <3 mg/L), and high-risk group (3 ≤ hs-CRP ≤10 mg/L). Definite diagnosis of hypertension in the follow-up survey in 2015 was the endpoint event of this study. The areas under the curve (AUC) of the receiver operating characteristic (ROC) curve analyses were used to evaluate the predictive value of the hs-CRP.

Results

3794 participants were finally included as study sample, of whom 912 developed hypertension during a 6-year follow-up period (incidence: 24.1%). The incidences of hypertension in hs-CRP low-risk, average-risk, and high-risk groups were 17.6% (200/1135), 25.9% (521/2015), and 29.7% (191/644), respectively. Spearman's correlation analyses showed that there was significant positive correlation between hs-CRP levels and waist circumference, total triglycerides, total cholesterol, age, body mass index, and homeostasis model assessment of insulin resistance index. Stepwise regression analyses showed that participants in the hs-CRP high-risk group had a 46.2% higher risk of developing hypertension compared with those in the hs-CRP low-risk group (odds ratio: 1.462, 95% confidence interval: 1.018–2.101). Baseline systolic and diastolic blood pressure levels and waist circumference contributed the most to the development of hypertension with R² of 0.076, 0.052, and 0.039, respectively, while hs-CRP had lower area under the curve (AUC) for hypertension, adding baseline BP and WC to the prediction model increased the AUC to 0.708 (95% CI: 0.681–0.735).

Conclusion

This study revealed a weak positive association between CRP levels and future incidence of hypertension in the Chinese population. The combination of hs-CRP with baseline BP and waist circumference (WC) had a higher predictive value for hypertension (AUC: 0.708), but the predictive value was still limited.

Examining chronic inflammatory markers on blood pressure measures in the presence of vitamin D insufficiency among indigenous cree adults: results from the cross-sectional Multi-Community Environment-and-Health Study in Eeyou Istchee, Quebec, Canada

OBJECTIVE

High blood pressure (BP) is a risk factor for cardiovascular disease. Examining the role of inflammatory mediators on BP is important since vitamin D (VD) is a modifiable risk factor, which possibly modulates inflammatory cytokines. This study simulated what are known as average 'controlled direct effects (CDE)' of inflammatory markers, C reactive protein (CRP), tumour necrosis factor-α (TNF-α), and interlukin-6 (IL-6) on continuous BP measures, while fixing VD, an intermediate variable to specific level.

DESIGN

Cross-sectional study.

SETTING

We analysed data from the Multi-Community Environment-and-Health Study, 2005-2009, conducted in Eeyou Istchee, Quebec, Canada.

PARTICIPANTS

This study recruited 1425 study Indigenous Cree participants from seven Cree communities. Only adults with serum VD levels, inflammatory markers and BP measures were included in this data analysis.

PRIMARY AND SECONDARY OUTCOMES MEASURES

Inflammatory markers examined the top 25th exposure percentiles. VD 'insufficiency' (ie, 25-hydroxyvitamin-D levels<50 nmol/L) defined by the Institute of Medicine. CDE for each inflammatory marker in the presence and absence of population VD insufficiency simulated the average direct effect change for systolic and diastolic BP (SBP and DBP) measures. All models were adjusted for exposure-and-mediator outcome relationship.

RESULTS

Among 161 participants, 97 (60 %) were female. The prevalence of VD insufficiency was 32%. CDE estimates show in the presence and absence of population vitamin D insufficiency, inflammatory markers have a slightly different association on BP. TNF-α significantly and inversely associated with SBP in the presence of vitamin D insufficiency, fully adjusted model β = -13.61 (95% CI -24.42 to -2.80); however, TNF-α was not associated with SBP in the absence of vitamin D insufficiency. CRP, IL-6 were also not significantly associated with BP measures, although the magnitude of association was greater for those with elevated inflammation and VD insufficiency.

CONCLUSION

This novel analysis shows in the presence of VD insufficiency, inflammation (particularly TNF-α) may affect SBP. Additional research is needed to elucidate these findings, and the temporal relationship between these variables.

[Characteristics of arterial hypertension clinical course in patients with obesity and anxiety-depressive disorders]

This article covers an important subject clinical course of arterial hypertension in patients with metabolic abnormalities with obesity and anxiety-depressive disorders. Relevance of this topic is defined with high incidence of each aforementioned conditions and their influence on quality of life and social functioning of patients. Review of literature covers subjects of comorbidity and multimorbidity. Relevant data are presented which are focusing on complex management of arterial hypertension co-existing with obesity and anxiety-depressive disorders.

The relationship between Plasma Markers and Essential Hypertension in Middle-aged and Elderly Chinese Population: A Community Based Cross-sectional Study

Plasma markers have been continuously advocated as pointers to estimate the long-term risk of cardiovascular disease in the general population. We examined the relationship between plasma high-sensitivity C-reactive protein (hs-CRP), homocysteine (Hcy), high-sensitivity cardiac troponin T (hs-cTnT), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), 25-Hydroxyvitamin D (25OHD), glycosylated hemoglobin A1c (HbA1c), and serum uric acid (SUA) levels and hypertension in middle and old aged population. A total of 2624 Chinese (62.02 ± 5.73 years old) were recruited into a population-based, cross-sectional study. Plasma hs-CRP, Hcy, HbA1c, and SUA levels were significantly higher in the hypertension group compared with control in the entire population and men (P = 0.05 for all). We observed a positive association between the highest quartiles of Hcy, NT-proBNP, HBA1c concentrations, and the prevalence of hypertension, OR (95% CI) = 1.48 (1.16–1.90), 1.62 (1.27–2.07) and 1.94 (1.49–2.52), respectively. The multivariable-adjusted OR of hypertension for the fourth versus the first quartile of homocysteine were 2.00 and 1.39 in men and women, respectively. In conclusion, our study found an independent and robust association between elevated Hcy, NT-ProBNP, and HBA1c levels and prevalence of hypertension in the middle-aged and elderly Chinese population. A follow-up study is necessary to endorse the observed association.

C-reactive protein and incident hypertension in a worksite population of Japanese men

Inflammation plays a key role in the pathogenesis of cardiovascular diseases via the development of atherosclerosis. Here, we evaluated the impact of serum C-reactive protein (CRP) and the white blood cell (WBC) count on the risk of hypertension in middle-aged Japanese men at a work site. We evaluated a total of 2991 Japanese male workers without hypertension who ranged in age from 18 to 64 years (mean age 40.4 ± 0.2 years) at a worksite in 2010. The hazard ratio (HR) for incident hypertension was estimated according to quartile levels of serum high-sensitivity CRP (hs-CRP) or WBC count. These men were followed up for 5 years from 2010 to 2015. During the follow-up period, 579 (19.4%) subjects developed hypertension. In a multivariable analysis, the risk of incident hypertension was significantly increased with higher hs-CRP levels: HR 1.00 (reference) for the lowest quartile, 1.39 (1.04-1.85) for the 2nd quartile, 1.46 (1.08-1.98) for the 3rd quartile, and 1.57 (1.17-2.11) for the highest quartile. In contrast, the WBC count was not associated with a greater risk of incident hypertension after multivariable adjustment. These findings suggest that higher levels of serum hs-CRP, but not the WBC count, are associated with the future incidence of hypertension in middle-aged Japanese men.

Inflammation in the Prediction of Type 2 Diabetes and Hypertension in Healthy Adults

BACKGROUND

While inflammation is associated with obesity and insulin resistance, their inter-relationships in the development of type 2 diabetes or hypertension are not clear.

AIM OF THE STUDY

To evaluate inflammatory markers in prediction of type 2 diabetes and hypertension.

METHODS

The study population of this retrospective cohort study consisted of individuals who participated in a comprehensive health screening program with measurement of white blood cell count and C-reactive protein from 2002-2010 (N = 96,606) in nondiabetic and normotensive Koreans. Median follow up time were 3.7 years for incident type 2 diabetes and 3.3 years for hypertension. Multivariate Cox proportional hazards models were performed to assess risk for type 2 diabetes or hypertension by white blood cell or C-reactive protein quartiles with adjustment of various possible confounding factors including insulin resistance.

RESULTS

During the follow-up period, 1448 (1.5%) developed type 2 diabetes and 10,405 (10.8%) developed hypertension. Among men, comparison of adjusted hazard ratios (HR) for incident type 2 diabetes in the highest versus lowest white blood cell or C-reactive protein quartiles were 1.48 [95% confidence interval (CI), 1.20-1.83] and 1.30 (95% CI, 1.07-1.57), respectively. Among women, white blood cell but not C-reactive protein was significantly associated with type 2 diabetes [HR 1.79 (95% CI 1.24-2.57)]. White blood cell and C-reactive protein quartiles were also modestly associated with incident hypertension in both sexes.

CONCLUSIONS

Although white blood cell and C-reactive protein are associated with adiposity and insulin resistance, these inflammatory markers also independently predict type 2 diabetes and/or hypertension.

CRP-level-associated polymorphism rs1205 within the CRP gene is associated with 2-hour glucose level: The SAPPHIRe study

C-reactive protein (CRP) encoded by CRP gene is a reflection of systemic inflammation. Many studies associated CRP level with diabetes and glucose levels, but the association of CRP gene with these traits is unclear. We conducted a cross-sectional study consisting of 945 siblings from 330 families collected by the Stanford Asian Pacific Program in Hypertension and Insulin Resistance (SAPPHIRe) to investigate associations between CRP polymorphisms, circulating CRP, diabetes, and glucose levels. Five single-nucleotide polymorphisms were analyzed: rs3093059, rs2794521, rs1417938, rs1800947, and rs1205. The generalized estimating equation approach was used to deal with correlated data within families. CRP level was positively correlated with diabetes prevalence and levels of fasting and 2-hour glucose (each P < 0.008). Alleles C at rs3093059 and G at rs1205 were associated with elevated CRP level (each P < 1.2 × 10⁻⁶). Allele C at rs3093059 was associated with fasting glucose (β = 0.20, P = 0.045) and G at rs1205 was associated with 2-hour glucose (β = 0.46, P = 0.00090) post oral glucose tolerance test, but only the latter passed Bonferroni correction. No polymorphism was associated with diabetes. Since 2-hour glucose is an indicator of glucose tolerance, this study indicated CRP gene is associated with glucose intolerance.

Adiponectin protects against incident hypertension independent of body fat distribution: observations from the Dallas Heart Study

BACKGROUND

Excess adipose tissue has been implicated in the pathogenesis of insulin resistance and atherosclerosis and is a key risk factor for blood pressure (BP) elevation. However, circulating levels of adiponectin, a protein produced by adipose tissue and widely implicated in the pathogenesis of insulin resistance and atherosclerosis, are inversely proportional to adiposity. The relationship between adiponectin and incident hypertension has not been determined in the general US population.

METHODS

Normotensive participants (n = 1233) enrolled in the Dallas Heart Study, a multiethnic, probability-based population sample of Dallas County adults were followed for median of 7 years. Retroperitoneal, intraperitoneal, visceral, and subcutaneous adipose tissue were measured at baseline by magnetic resonance imaging. Liver fat content was measured by ¹ H-magnetic resonance spectroscopy. Relative risk regression was used to determine the association of adiponectin with incident hypertension after adjustment for age, race, sex, BMI, smoking, diabetes, baseline systolic BP, total cholesterol, and regional fat depot.

RESULTS

Of the 1233 study participants (median age 40 years, 40% black, and 56% women), 391 (32%) had developed hypertension over a median follow-up of 7 years. Adiponectin levels were associated with reduced risk of incident hypertension (RR 0.81, 95% CI [0.68-0.96]) in the fully adjusted model, which included liver fat. Similar results were observed after adjustment for subcutaneous or visceral fat depots when tested individually or simultaneously in the model.

CONCLUSION

Our study suggested a protective role of adiponectin against incident hypertension independent of body fat distribution.

Plasma Inflammatory Markers and the Risk of Developing Hypertension in Men

Background

Several cross-sectional, but few prospective, studies suggest that inflammation may be involved in the development of hypertension. We examined markers of inflammation—high-sensitivity C-reactive protein, interleukin-6, and soluble intercellular adhesion molecule-1—and a marker of fibrinolysis, D-dimer, for their associations with incident hypertension in the Physicians’ Health Study.

Methods and Results

Baseline blood values and information on hypertension-related risk factors were collected in 1982. Incident hypertension was defined as self-reported initiation of antihypertensive treatment, systolic blood pressure ≥140 mm Hg, or diastolic blood pressure ≥90 mm Hg during follow-up. With use of a nested case-control design, 396 cases of incident hypertension and controls free of hypertension were matched 1:1 on age (mean 47.4 years) and follow-up time. In crude matched-pair analyses, the conditional relative risks of hypertension in the second through fourth versus the lowest quartiles for plasma high-sensitivity C-reactive protein were 1.27, 1.73, and 1.81 (P_trend=0.01); for interleukin-6, 1.22, 1.02, and 1.51 (P_trend=0.06); for soluble intercellular adhesion molecule-1, 1.00, 0.80, and 1.26 (P_trend=0.37); and for D-dimer, 1.61, 1.81, and 1.52 (P_trend=0.46). Multivariable adjustment attenuated the estimates. The multivariable relative risks of hypertension in the second through fourth compared to the lowest quartiles of high-sensitivity C-reactive protein were 1.24, 1.60, and 1.47 (P_trend=0.20); for interleukin-6, 1.08, 0.92, and 1.36 (P_trend=0.16); for soluble intercellular adhesion molecule-1, 0.89, 0.79, and 1.18 (P_trend=0.55); and for D-dimer, 1.48, 1.68, and 1.38 (P_trend=0.63).

Conclusions

Elevated plasma inflammatory markers and D-dimer were nonsignificantly associated with a higher risk of hypertension among initially healthy men.

Diagnostic and predictive accuracy of blood pressure screening methods with consideration of rescreening intervals: a systematic review for the U.S. Preventive Services Task Force

BACKGROUND

Elevated blood pressure (BP) is the largest contributing risk factor to all-cause and cardiovascular mortality.

PURPOSE

To update a systematic review on the benefits and harms of screening for high BP in adults and to summarize evidence on rescreening intervals and diagnostic and predictive accuracy of different BP methods for cardiovascular events.

DATA SOURCES

Selected databases searched through 24 February 2014.

STUDY SELECTION

Fair- and good-quality trials and diagnostic accuracy and cohort studies conducted in adults and published in English.

DATA EXTRACTION

One investigator abstracted data, and a second checked for accuracy. Study quality was dual-reviewed.

DATA SYNTHESIS

Ambulatory BP monitoring (ABPM) predicted long-term cardiovascular outcomes independently of office BP (hazard ratio range, 1.28 to 1.40, in 11 studies). Across 27 studies, 35% to 95% of persons with an elevated BP at screening remained hypertensive after nonoffice confirmatory testing. Cardiovascular outcomes in persons who were normotensive after confirmatory testing (isolated clinic hypertension) were similar to outcomes in those who were normotensive at screening. In 40 studies, hypertension incidence after rescreening varied considerably at each yearly interval up to 6 years. Intrastudy comparisons showed at least 2-fold higher incidence in older adults, those with high-normal BP, overweight and obese persons, and African Americans.

LIMITATION

Few diagnostic accuracy studies of office BP methods and protocols in untreated adults.

CONCLUSION

Evidence supports ABPM as the reference standard for confirming elevated office BP screening results to avoid misdiagnosis and overtreatment of persons with isolated clinic hypertension. Persons with BP in the high-normal range, older persons, those with an above-normal body mass index, and African Americans are at higher risk for hypertension on rescreening within 6 years than are persons without these risk factors.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

Association between CRP gene polymorphisms and the risk of preeclampsia in Han Chinese women

BACKGROUND

As an inflammatory marker, C-reactive protein (CRP) has elevated expression in preeclampsia (PE), which is implicated in the pathogenesis of PE, but there has been a lack of information on the possible association between genetic variants of CRP and PE. In this study, we aimed to assess the genetic association between CRP polymorphisms and the risk of PE in Han Chinese Women.

METHODS

Five single-nucleotide polymorphisms of CRP, rs2794521 (T>C), rs3091244 (C>T>A), rs3093068 (C>G), rs876538 (C>T), and rs1205 (C>T) were genotyped using the Sequenom method in 181 PE patients and 203 controls.

RESULTS

The T allele frequency for rs2794521 was significantly higher in PE patients than in controls (odds ratios [OR]=4.091; 95% confidence interval [CI]: 1.533-10.917; p=0.002). The TT genotype of rs2794521 conferred a risk for PE (TT vs. TC+CC: OR=4.062; 95% CI: 1.499-11.008; p=0.003) and severe PE (TT vs. TC+CC: OR=9.577; 95% CI: 1.267-72.397; p=0.006). The other four polymorphic loci were not different between the groups. The CRP H2 haplotype (T-C-C-G-C) was associated with PE (OR=2.129; 95% CI: 1.47-3.085; p<0.001), whereas the H1 haplotype (C-C-C-G-C) offered protection (OR=0.23; 95% CI: 0.066-0.8; p=0.01).

CONCLUSIONS

The CRP variant rs2794521 shows a strong association with PE in Han Chinese women. Pregnant women with the TT genotype of rs2794521 have higher odds of having PE, which further supports a possible role for CRP in PE.

In prehypertension leukocytosis is associated with body mass index but not with blood pressure or incident hypertension

BACKGROUND

Previous studies reported increased white blood cell counts (WBCCs), an inflammatory marker, in hypertension, prehypertension and metabolic syndrome. Evidence suggests that inflammation precedes blood pressure (BP) elevation and may contribute to incident hypertension. Angiotensin receptor blockers (ARBs) may reduce inflammation. We analyzed WBCC trends in TRial Of Preventing HYpertension (TROPHY) to determine if this inflammatory marker predicted incident hypertension in prehypertensive individuals and whether randomized assignment to the ARB candesartan (391 individuals) for 2 years, lowered WBCC compared with placebo-treated controls (381 individuals).

METHODS

A new analysis of TROPHY trial data.

RESULTS

In the total population, baseline BMI correlated with WBCC (r = 0.185, P < 0.0001), neutrophils (r = 0.135, P < 0.001) and lymphocytes (r = 0.204, P < 0.0001). Baseline triglycerides also correlated significantly with inflammatory markers. Despite a wide range of home BP (HBP) values, HBP did not correlate with baseline WBCC counts. After 2 years, candesartan decreased placebo corrected HBP by -5.5/-2.5 mmHg, (P < 0.0001), but WBCC, neutrophil and lymphocyte counts were not different in placebo and in candesartan groups. Baseline WBCC, neutrophils and lymphocyte counts did not predict incident hypertension in the placebo group.

CONCLUSION

In TROPHY, candesartan lowered BP but did not alter WBCC. Baseline WBCC did not predict incident hypertension. Our findings do not support the hypothesis that inflammation contributes to incident hypertension or that ARB treatment suppresses inflammation. The significant independent association of WBCC with baseline BMI and triglycerides is consistent with the evidence that obesity and insulin resistance are associated with inflammation. The findings highlight the importance of effective lifestyle modification in prehypertension to reduce inflammatory cardio-metabolic risk and suppress transition to hypertension.

Plasma advanced glycation end products (AGEs) and NF-κB activity are independent determinants of diastolic and pulse pressure

BACKGROUND

High levels of circulating advanced glycation end products (AGEs) can initiate chronic low-grade activation of the immune system (CLAIS) with each of these factors independently associated with cardiovascular (CV) morbidity and mortality. Therefore, our objective was to characterize the relationship between serum AGEs, CLAIS and other risk factors for CV disease in normotensive non-diabetic individuals.

METHODS

We measured body mass index (BMI), waist-to-hip ratio (WHR), blood pressure, lipid and glucose profile in 44 non-diabetic volunteers (17 female, 27 males). Carboxymethyl-lysine (CML) was measured by ELISA as a marker for circulating AGEs and NF-κB p65 activity as an inflammatory marker by DNA-binding in peripheral blood mononuclear cells lysates (PBMC).

RESULTS

Plasma CML concentrations were related to diastolic blood pressure (r=-0.51, p<0.01) independently of age, sex, BMI and WHR (p<0.05). Diastolic blood pressure was also related to NF-κB activity in PBMC (r=0.47, p<0.01) before and after adjustment for age, sex, BMI and WHR (p<0.05). Plasma CML concentrations were related to the pulse pressure before (r=0.42; p<0.05) and after adjustment for age, sex, BMI and waist (p<0.05). Neither CML nor NF-κB activity were related to systolic blood pressure (both p=ns). Plasma CML concentrations were not associated with plasma lipid or glucose concentrations (all p=ns).

CONCLUSIONS

Plasma AGE levels and NF-κB activity in PBMC were independent determinants of diastolic and pulse pressure in healthy normotensive individuals. This association suggests a role for AGEs in the etiology of hypertension, possibly via the initiation of CLAIS and aortic stiffening.

The association between smoking quantity and hypertension mediated by inflammation in Chinese current smokers

OBJECTIVES

Previous studies indicated that cigarette smokers were more likely to develop hypertension, and both smoking and hypertension were associated with inflammation. Whether inflammation mediates the relationship of them is unclear. This study aims to examine whether inflammation mediates the association between smoking and hypertension.

METHODS

Nine hundred and eighty-four Chinese current smokers from a community-based chronic diseases survey in Guangzhou and Zhuhai were interviewed about sociodemographics, smoking, chronic conditions, and other health-related variables. Hypertension was defined according to 2007 European Society of Hypertension and European Society of Cardiology (ESH-ESC) Practice Guidelines. Inflammatory markers including C-reactive protein (CRP), interleukin (IL)-6, IL-1β, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), and vascular cell adhesion molecule-1 (VCAM-1) were measured by flow cytometry. Logistic regressions were performed to assess the mediation of inflammation on the relationship between smoking quantity and hypertension.

RESULTS

We observed a positive association between smoking quantity and hypertension (P<0.05). After controlling for potential confounders, daily cigarette consumption was significantly associated with higher level of CRP and VCAM-1 and lower level of TNF-α among six measured inflammatory markers, and the current smokers with hypertension had significantly higher level of MCP-1 and CRP than those smokers who were normotensive. Furthermore, the association between smoking quantity and hypertension was mediated by CRP, which accounted for 58.59% of the estimated causal effect of smoking on hypertension.

CONCLUSION

We have confirmed previous observations that smoking quantity was positively associated with hypertension, and the results of our study suggested that the association between smoking and hypertension was probably mediated by CRP.

Association of inflammatory cytokines and endothelial adhesion molecules with immunological, virological, and cardiometabolic disease in HIV-infected individuals

Elevated levels of inflammatory and endothelial biomarkers are related to chronic diseases, cancers, and cardiovascular disease. This study aimed at evaluating the association of inflammatory cytokines and endothelial adhesion molecules with immunological, virological, and cardiometabolic disease in HIV-infected individuals. A cross-sectional study was initiated to evaluate the association of CD4 lymphocyte count, viral load, antiretroviral therapy, and metabolic and cardiovascular disease with inflammatory cytokines [interleukin (IL)-1β, IL-6, and tumor necrosis factor α (TNF-α)], adhesion molecules [soluble intercellular Adhesion Molecule 1 (sICAM) and soluble Vascular Adhesion Molecule 1 (sVCAM)], and highsensitive C-reactive protein (hs-CRP) levels in 125 HIV-infected patients. The associations between independent variables and biomarkers were analyzed by means of multivariate logistic regression. A viral load ≥100,000 copies/mL had a stronger association with high levels of sVCAM-1 (P=0.026; OR=2.54; CI=1.12-5.78) and TNF-α (P=0.048; OR=2.42; CI=1.01-5.85) than the current viral load using a multivariate analysis. Antiretroviral treatment was associated with lower levels of sVCAM-1 (P=0.20; OR=0.20; CI=0.05-0.78), TNF-α (P=0.060; OR=0.22; CI=0.05-1.07), and hs-CRP (P=0.093; OR=0.44; CI=0.17-1.15). CD4 counts <200 cells/mm(3) were associated with high IL-6 levels (P=0.013; OR=3.17; CI=1.27-7.91); however, antiretroviral treatment was not associated with IL-6 levels. Metabolic syndrome was associated with high hs-CRP levels, systolic hypertension was associated with IL-6 levels, and family history of coronary disease was associated with TNF-α levels. High biomarker levels were associated not only with viral and immunological characteristics but also with cardiometabolic factors. The maximum viral load attained was an important risk factor for high levels of TNF-α and sVCAM-1. Treatment protected patients from high biomarker levels, except IL-6.

Effects of heme oxygenase-1 upregulation on blood pressure and cardiac function in an animal model of hypertensive myocardial infarction

In this study, we evaluate the effect of HO-1 upregulation on blood pressure and cardiac function in the new model of infarct spontaneous hypertensive rats (ISHR). Male spontaneous hypertensive rats (SHR) at 13 weeks (n = 40) and age-matched male Wistar (WT) rats (n = 20) were divided into six groups: WT (sham + normal saline (NS)), WT (sham + Co(III) Protoporphyrin IX Chloride (CoPP)), SHR (myocardial infarction (MI) + NS), SHR (MI + CoPP), SHR (MI + CoPP + Tin Mesoporphyrin IX Dichloride (SnMP)), SHR (sham + NS); CoPP 4.5 mg/kg, SnMP 15 mg/kg, for six weeks, one/week, i.p., n = 10/group. At the sixth week, echocardiography (UCG) and hemodynamics were performed. Then, blood samples and heart tissue were collected. Copp treatment in the SHR (MI + CoPP) group lowered blood pressure, decreased infarcted area, restored cardiac function (left ventricular ejection fraction (LVEF), left ventricular fraction shortening (LVFS), +dp/dt_max, (−dp/dt_max)/left ventricular systolic pressure (LVSP)), inhibited cardiac hypertrophy and ventricular enlargement (downregulating left ventricular end-systolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD) and heart weight/body weight (HW/BW)), lowered serum CRP, IL-6 and Glu levels and increased serum TB, NO and PGI2 levels. Western blot and immunohistochemistry showed that HO-1 expression was elevated in the SHR (MI + CoPP) group, while co-administration with SnMP suppressed the benefit functions mentioned above. In conclusion, HO-1 upregulation can lower blood pressure and improve post-infarct cardiac function in the ISHR model. These functions may be involved in the inhibition of inflammation and the ventricular remodeling process and in the amelioration of glucose metabolism and endothelial dysfunction.

Isoprostanes and isofurans as non-traditional risk factors for cardiovascular disease among Canadian Inuit

OBJECTIVES

The aim of the present study was to investigate the potential importance of oxidative stress, measured by isoprostanes-related compounds, as non-traditional risk factor for cardiovascular disease. We planned to examine the relationship between concentrations of plasma F₂-isoprostanes (F₂-IsoPs), isofurans (IsoFs), measures of obesity and various cardiometabolic risk factors.

MATERIALS AND METHODS

Cross-sectional study using a sub-sample from the population of a survey conducted in the summer and fall 2007 and 2008 by Canadian Coastguard Ship Amundsen in 36 Canadian Arctic Inuit communities. Subjects included a subset (n = 233) of a total study population (n = 2595) with a mean age 42.56 ± 15.39 years and body mass index 27.78 ± 5.65 kg/m². Plasma levels of F₂-IsoPs and IsoFs was determined by gas chromatography/negative ion chemical ionization/mass spectrometry (GC/NICI/MS) method; and their relationships to waist circumference (WC), blood pressure C reactive proteins (CRP), blood lipids and fasting glucose were assessed by multivariate analyses.

RESULTS

Plasma F₂-IsoPs correlated positively with CRP (r =.132, P =.048) and systolic blood pressure (SBP) (r =.157, P =.024) after adjustment for age, sex and body mass index. IsoFs correlated with WC (r =.190, P =.005) and SBP (r =.137, P =.048). F2-IsoPs were not found elevated in smokers (P =.034), whereas IsoFs were decreased in smokers (P =.001). WC, SBP and sex were found to be major correlates of oxidative stress in Canadian Inuit.

CONCLUSIONS

Plasma measures of F₂-IsoPs and IsoFs increase with increased obesity and associated cardiometabolic risk factors, including CRP and blood pressure. Simultaneous measurement of IsoFs provides an advantageous mechanistic insight into oxidative stress not captured by F₂-IsoPs alone.

Angiotensin II, Aldosterone, and Anti-Inflammatory Lymphocytes: Interplay and Therapeutic Opportunities

Inflammation is recognized as an important factor in the pathophysiology of hypertension, with the renin-angiotensin-aldosterone system (RAAS) playing a key role in the disease. Initially described because of its contribution to extracellular fluid and electrolyte homeostasis, the RAAS has been implicated in endothelial dysfunction, vascular remodeling, oxidative stress, proinflammatory cytokine production, and adhesion molecule synthesis by the vascular wall. Both angiotensin II and aldosterone are involved in these systemic effects, activating innate and adaptive immune responses. This paper highlights some aspects connecting RAAS to the hypertensive phenotype, based on experimental and clinical studies, with emphasis on new findings regarding the contribution of an increasingly studied population of T lymphocytes: the T-regulatory lymphocytes. These cells can suppress inflammation and may exert beneficial vascular effects in animal models of hypertension.

Inflammatory markers and blood pressure: sex differences and the effect of fat mass in the CoLaus Study

Several studies have reported high levels of inflammatory biomarkers in hypertension, but data coming from the general population are sparse, and sex differences have been little explored. The CoLaus Study is a cross-sectional examination survey in a random sample of 6067 Caucasians aged 35-75 years in Lausanne, Switzerland. Blood pressure (BP) was assessed using a validated oscillometric device. Anthropometric parameters were also measured, including body composition, using electrical bioimpedance. Crude serum levels of interleukin-6 (IL-6), tumor necrosis factor α (TNF-α) and ultrasensitive C-reactive protein (hsCRP) were positively and IL-1β (IL-1β) negatively (P<0.001 for all values), associated with BP. For IL-6, IL-1β and TNF-α, the association disappeared in multivariable analysis, largely explained by differences in age and body mass index, in particular fat mass. On the contrary, hsCRP remained independently and positively associated with systolic (β (95% confidence interval): 1.15 (0.64; 1.65); P<0.001) and diastolic (0.75 (0.42; 1.08); P<0.001) BP. Relationships of hsCRP, IL-6 and TNF-α with BP tended to be stronger in women than in men, partly related to the difference in fat mass, yet the interaction between sex and IL-6 persisted after correction for all tested confounders. In the general population, the associations between inflammatory biomarkers and rising levels of BP are mainly driven by age and fat mass. The stronger associations in women suggest that sex differences might exist in the complex interplay between BP and inflammation.