Mean red cell volume as a correlate of blood pressure

White blood cell and platelet distribution widths are associated with hypertension: data mining approaches

In this paper, we are going to investigate the association between Hypertension (HTN) and routine hematologic indices in a cohort of Iranian adults. The data were obtained from a total population of 9704 who were aged 35-65 years, a prospective study was designed. The association between hematologic factors and HTN was assessed using logistic regression (LR) analysis and a decision tree (DT) algorithm. A total of 9704 complete datasets were analyzed in this cohort study (N = 3070 with HTN [female 62.47% and male 37.52%], N = 6634 without HTN [female 58.90% and male 41.09%]). Several variables were significantly different between the two groups, including age, smoking status, BMI, diabetes millitus, high sensitivity C-reactive protein (hs-CRP), uric acid, FBS, total cholesterol, HGB, LYM, WBC, PDW, RDW, RBC, sex, PLT, MCV, SBP, DBP, BUN, and HCT (P < 0.05). For unit odds ratio (OR) interpretation, females are more likely to have HTN (OR = 1.837, 95% CI = (1.620, 2.081)). Among the analyzed variables, age and WBC had the most significant associations with HTN OR = 1.087, 95% CI = (1.081, 1.094) and OR = 1.096, 95% CI = (1.061, 1.133), respectively (P-value < 0.05). In the DT model, age, followed by WBC, sex, and PDW, has the most significant impact on the HTN risk. Ninety-eight percent of patients had HTN in the subgroup with older age (≥58), high PDW (≥17.3), and low RDW (<46). Finally, we found that elevated WBC and PDW are the most associated factor with the severity of HTN in the Mashhad general population as well as female gender and older age.

Aging in Normotensive and Spontaneously Hypertensive Rats: Focus on Erythrocyte Properties

Erythrocyte deformability, crucial for oxygen delivery to tissues, plays an important role in the etiology of various diseases. As the factor maintaining the erythrocyte deformability, nitric oxide (NO) has been identified. Reduced NO bioavailability also plays a role in the pathogenesis of hypertension. Our aim was to determine whether aging and hypertension affect erythrocyte deformability and NO production by erythrocytes in experimental animals divided into six groups according to age (7, 20 and 52 weeks), labeled WKY-7, WKY-20 and WKY-52 for normotensive Wistar-Kyoto (WKY) rats, and SHR-7, SHR-20 and SHR-52 for spontaneously hypertensive rats (SHR). The filtration method for the determination of erythrocyte deformability and the fluorescent probe DAF-2 DA for NO production were applied. Deformability and NO production by erythrocytes increased at a younger age, while a decrease in both parameters was observed at an older age. Strain-related differences in deformability were observed at 7 and 52 weeks of age. SHR-7 had reduced deformability and SHR-52 had increased deformability compared with age-matched WKY. Changes in NO production under hypertensive conditions are an unlikely primary factor affecting erythrocyte deformability, whereas age-related changes in deformability are at least partially associated with changes in NO production. However, an interpretation of data obtained in erythrocyte parameters observed in SHRs of human hypertension requires precaution.

A Mendelian randomization-based exploration of red blood cell distribution width and mean corpuscular volume with risk of hemorrhagic strokes

Red blood cell distribution width (RCDW) and mean corpuscular volume (MCV) are associated with different risk factors for hemorrhagic stroke. However, whether RCDW and MCV are causally related to hemorrhagic stroke remains poorly understood. Therefore, we explored the causality between RCDW/MCV and nontraumatic hemorrhagic strokes using Mendelian randomization (MR) methods. We extracted exposure and outcome summary statistics from the UK Biobank and FinnGen. We evaluated the causality of RCDW/MCV on four outcomes (subarachnoid hemorrhage [SAH], intracerebral hemorrhage [ICH], nontraumatic intracranial hemorrhage [nITH], and a combination of SAH, cerebral aneurysm, and aneurysm operations) using univariable MR (UMR) and multivariable MR (MVMR). We further performed colocalization and mediation analyses. UMR and MVMR revealed that higher genetically predicted MCV is protective of ICH (UMR: odds ratio [OR] = 0.89 [0.8-0.99], p = 0.036; MVMR: OR = 0.87 [0.78-0.98], p = 0.021) and nITH (UMR: OR = 0.89 [0.82-0.97], p = 0.005; MVMR: OR = 0.88 [0.8-0.96], p = 0.004). There were no strong causal associations between RCDW/MCV and any other outcome. Colocalization analysis revealed a shared causal variant between MCV and ICH; it was not reported to be associated with ICH. Proportion mediated via diastolic blood pressure was 3.1% (0.1%,14.3%) in ICH and 3.4% (0.2%,15.8%) in nITH. The study constitutes the first MR analysis on whether genetically elevated RCDW and MCV affect the risk of hemorrhagic strokes. UMR, MVMR, and mediation analysis revealed that MCV is a protective factor for ICH and nITH, which may inform new insights into the treatments for hemorrhagic strokes.

GWAS and PheWAS of red blood cell components in a Northern Nevadan cohort

In this study, we perform a full genome-wide association study (GWAS) to identify statistically significantly associated single nucleotide polymorphisms (SNPs) with three red blood cell (RBC) components and follow it with two independent PheWASs to examine associations between phenotypic data (case-control status of diagnoses or disease), significant SNPs, and RBC component levels. We first identified associations between the three RBC components: mean platelet volume (MPV), mean corpuscular volume (MCV), and platelet counts (PC), and the genotypes of approximately 500,000 SNPs on the Illumina Infimum DNA Human OmniExpress-24 BeadChip using a single cohort of 4,673 Northern Nevadans. Twenty-one SNPs in five major genomic regions were found to be statistically significantly associated with MPV, two regions with MCV, and one region with PC, with p<5x10^-8. Twenty-nine SNPs and nine chromosomal regions were identified in 30 previous GWASs, with effect sizes of similar magnitude and direction as found in our cohort. The two strongest associations were SNP rs1354034 with MPV (p = 2.4x10^-13) and rs855791 with MCV (p = 5.2x10^-12). We then examined possible associations between these significant SNPs and incidence of 1,488 phenotype groups mapped from International Classification of Disease version 9 and 10 (ICD9 and ICD10) codes collected in the extensive electronic health record (EHR) database associated with Healthy Nevada Project consented participants. Further leveraging data collected in the EHR, we performed an additional PheWAS to identify associations between continuous red blood cell (RBC) component measures and incidence of specific diagnoses. The first PheWAS illuminated whether SNPs associated with RBC components in our cohort were linked with other hematologic phenotypic diagnoses or diagnoses of other nature. Although no SNPs from our GWAS were identified as strongly associated to other phenotypic components, a number of associations were identified with p-values ranging between 1x10^-3 and 1x10^-4 with traits such as respiratory failure, sleep disorders, hypoglycemia, hyperglyceridemia, GERD and IBS. The second PheWAS examined possible phenotypic predictors of abnormal RBC component measures: a number of hematologic phenotypes such as thrombocytopenia, anemias, hemoglobinopathies and pancytopenia were found to be strongly associated to RBC component measures; additional phenotypes such as (morbid) obesity, malaise and fatigue, alcoholism, and cirrhosis were also identified to be possible predictors of RBC component measures.

Hematologic disorders during essential hypertension

BACKGROUND

Besides the traditional risk factors, hematological changes may be involved in the development of arterial hypertension and in its pathogenesis.

METHODS

The study, conducted on a sample of 545 subjects, 215 with hypertension and 330 witnesses, were evaluated for peripheral blood parameters in western Algeria; Logistic regression analysis was used to predict hypertension with hematological parameters.

RESULTS

The characters studied related significantly; lower red blood cell levels have a three-and-a-half-fold risk of developing hypertension compared to those who have normal red blood cell counts (OR = 3.64, 95% CI = 1.37-9.65, p < 0.05). Subjects who have mean corpuscular volume rate below 80 fl are more exposed to hypertension (OR = 13.58, 95% CI = 4.68-39.41, p = 0.000). The mean corpuscular hemoglobin concentration reveals that subjects who have a lower than normal (<27 pg) are once less exposed to hypertension (OR = 0.04, 95% CI = 0.01-0.13, p = 0.000). Subjects who have lower platelet count than normal are twelve times more exposed to hypertension (OR = 12.13, 95% CI = 1.45-101.18, P = 0.021). Finally, the increase in sedimentation rate at one hour increases the risk of hypertension by 56.63 times compared to subjects with normal sedimentation rate (OR = 56.63, 95% CI = 3.37-597.33, P = 0.001).

CONCLUSIONS

Hematological profile associated with essential hypertension retained Red blood cells ratio, mean corpuscular volume, mean corpuscular hemoglobin concentration, platelet ratio, and sedimentation rate at one hour.

Association of hematocrit with blood pressure and hypertension

BACKGROUND

Hypertension (HTN) is a risk factor for stroke, renal failure, and cardiovascular disease. The association between biochemical and hematological parameters with high blood pressure may provide a more precise approach to risk prediction conferred by HTN in these patients.

OBJECTIVE

The aim of current study was to explore whether biochemical and hematological parameters are associated with HTN in a cohort study with a 7-year follow-up.

MATERIALS AND METHODS

A total of 9808 individuals were enrolled and recruited as part of the Mashhad Stroke and Heart Atherosclerotic Disorders (MASHAD) cohort study, and biochemical and hematological factors were measured in all subjects. Univariate and multivariate logistic regression analysis were performed to determine the association of biochemical and hematological parameters with HTN.

RESULTS

Several biochemical parameters including fasting plasma glucose (FBG), serum high-sensitivity C-reactive protein (hs-CRP), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and uric acid were increased in hypertensive participants. In contrast, serum high-density lipoprotein cholesterol (HDL-C) was lower in hypertensive individuals. Furthermore, we demonstrated that hematological parameters including white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin (HGB), hematocrit (HCT), and mean corpuscular hemoglobin (MCH) were higher in the hypertensive group compared to the control group. But mean corpuscular volume (MCV), and red cell distribution width (RDW), were decreased in the hypertensive group. Furthermore, our results strongly suggested that among these parameters, hematocrit was the independent risk factor for hypertension in the population.

CONCLUSION

We demonstrated the association of altered biochemical and hematological factors with hypertension supporting the value of emerging markers for early prediction of high blood pressure in prone individuals.

Clinical implication of hematological indices in the essential hypertension

Prognostic value of haematological indices, especially red cell distribution width, neutrophil lymphocyte ratio and mean platelet volume, was reported with numerous investigations in miscellaneous cardiovascular settings. Their major prognostic value was linked to oxidative stress and inflammation since their level was correlated with major inflammatory markers such as high sensitive C-reactive protein and interleukins. Oxidative stress and chronic inflammation are also postulated as the main pathophysiologic mechanism of essential hypertension (HT) and its vascular complication. Recently, correlation between HT and haematological parameters was searched in numerous studies, which has made the topic more popular. Herein, we reveal the correlation between haematological indices and HT and we also demonstrate the clinical implication of this correlation. Impaired haematological parameters may strongly indicate hypertensive end-organ damage.

Spontaneous white matter damage, cognitive decline and neuroinflammation in middle-aged hypertensive rats: an animal model of early-stage cerebral small vessel disease

Introduction

Cerebral small vessel disease (cSVD) is one of the most prevalent neurological disorders. The progressive remodeling of brain microvessels due to arterial hypertension or other vascular risk factors causes subtle, but constant cognitive decline through to manifest dementia and substantially increases the risk for stroke. Preliminary evidence suggests the contribution of the immune system to disease initiation and progression, but a more detailed understanding is impaired by the unavailability of appropriate animal models. Here, we introduce the spontaneously hypertensive rat (SHR) as a model for early onset cSVD and unveiled substantial immune changes in conjunction with brain abnormalities that resemble clinical findings.

Results

In contrast to age-matched normotensive Wistar Kyoto (WKY) rats, male SHR exhibited non-spatial memory deficits. Magnetic resonance imaging showed brain atrophy and a reduction of white matter volumes in SHR. Histological analyses confirmed white matter demyelination and unveiled a circumscribed blood brain barrier dysfunction in conjunction with micro- and macrogliosis in deep cortical regions. Flow cytometry and histological analyses further revealed substantial disparities in cerebral CD45high leukocyte counts and distribution patterns between SHR and WKY. SHR showed lower counts of T cells in the choroid plexus and meningeal spaces as well as decreased interleukin-10 levels in the cerebrospinal fluid. On the other hand, both T and NK cells were significantly augmented in the SHR brain microvasculature.

Conclusions

Our results indicate that SHR share behavioral and neuropathological characteristics with human cSVD patients and further undergird the relevance of immune responses for the initiation and progression of cSVD.

Electronic supplementary material

The online version of this article (doi:10.1186/s40478-014-0169-8) contains supplementary material, which is available to authorized users.

Genetic variants that confer resistance to malaria are associated with red blood cell traits in African-Americans: an electronic medical record-based genome-wide association study

To identify novel genetic loci influencing interindividual variation in red blood cell (RBC) traits in African-Americans, we conducted a genome-wide association study (GWAS) in 2315 individuals, divided into discovery (n = 1904) and replication (n = 411) cohorts. The traits included hemoglobin concentration (HGB), hematocrit (HCT), RBC count, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). Patients were participants in the electronic MEdical Records and GEnomics (eMERGE) network and underwent genotyping of ~1.2 million single-nucleotide polymorphisms on the Illumina Human1M-Duo array. Association analyses were performed adjusting for age, sex, site, and population stratification. Three loci previously associated with resistance to malaria—HBB (11p15.4), HBA1/HBA2 (16p13.3), and G6PD (Xq28)—were associated (P ≤ 1 × 10⁻⁶) with RBC traits in the discovery cohort. The loci replicated in the replication cohort (P ≤ 0.02), and were significant at a genome-wide significance level (P < 5 × 10⁻⁸) in the combined cohort. The proportions of variance in RBC traits explained by significant variants at these loci were as follows: rs7120391 (near HBB) 1.3% of MCHC, rs9924561 (near HBA1/A2) 5.5% of MCV, 6.9% of MCH and 2.9% of MCHC, and rs1050828 (in G6PD) 2.4% of RBC count, 2.9% of MCV, and 1.4% of MCH, respectively. We were not able to replicate loci identified by a previous GWAS of RBC traits in a European ancestry cohort of similar sample size, suggesting that the genetic architecture of RBC traits differs by race. In conclusion, genetic variants that confer resistance to malaria are associated with RBC traits in African-Americans.

Serum alanine aminotransferase is correlated with hematocrit in healthy human subjects

BACKGROUND

Serum alanine aminotransferase (ALT) activity is a widely-used surrogate marker for liver injury. However, mild elevation of serum ALT is frequently observed in apparently healthy individuals, making it sometimes challenging to interpret whether this laboratory abnormality is medically benign or serious. To obtain a better understanding of the factors influencing ALT levels, we examined the relation between ALT and a number of anthropometric and biochemistry measurements in humans.

METHODS

We assessed the associations of ALT with hematocrit (HCT) in 1,200 apparently healthy adults from an Amish population. Multivariate analyses were carried out to determine whether observed associations were independent of other factors known to modulate ALT and HCT, including body mass index (BMI) and sex. The correlation detected in the Amish was then replicated in an independent population sample (N = 9,842) from the National Health and Nutrition Examination Survey (NHANES) III.

RESULTS

ALT levels were positively correlated with HCT (r = 0.33, p < 0.0001) in both Amish and NHANES III. The magnitude of association was unchanged after adjustment for BMI, but was reduced by age/sex adjustment to r = 0.18 (p < 0.0001) and r = 0.17 (p < 0.0001) in the Amish and NHANES populations, respectively. HCT accounts for about 3% of the population variation in ALT, which is smaller than the contributions of gender and BMI, but larger than individual blood pressure and cholesterol components.

CONCLUSIONS

We observed a correlation between ALT and HCT, suggesting that HCT may be a newly identified modulator of ALT in humans.

A genome-wide association study of red blood cell traits using the electronic medical record

Background

The Electronic Medical Record (EMR) is a potential source for high throughput phenotyping to conduct genome-wide association studies (GWAS), including those of medically relevant quantitative traits. We describe use of the Mayo Clinic EMR to conduct a GWAS of red blood cell (RBC) traits in a cohort of patients with peripheral arterial disease (PAD) and controls without PAD.

Methodology and Principal Findings

Results for hemoglobin level, hematocrit, RBC count, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were extracted from the EMR from January 1994 to September 2009. Out of 35,159 RBC trait values in 3,411 patients, we excluded 12,864 values in 1,165 patients that had been measured during hospitalization or in the setting of hematological disease, malignancy, or use of drugs that affect RBC traits, leaving a final genotyped sample of 3,012, 80% of whom had ≥2 measurements. The median of each RBC trait was used in the genetic analyses, which were conducted using an additive model that adjusted for age, sex, and PAD status. We identified four genomic loci that were associated (P<5×10⁻⁸) with one or more of the RBC traits (HBLS1/MYB on 6q23.3, TMPRSS6 on 22q12.3, HFE on 6p22.1, and SLC17A1 on 6p22.2). Three of these loci (HBLS1/MYB, TMPRSS6, and HFE) had been identified in recent GWAS and the allele frequencies, effect sizes, and the directions of effects of the replicated SNPs were similar to the prior studies.

Conclusions

Our results demonstrate feasibility of using the EMR to conduct high throughput genomic studies of medically relevant quantitative traits.

Multiple loci influence erythrocyte phenotypes in the CHARGE Consortium

Measurements of erythrocytes within the blood are important clinical traits and can indicate various hematological disorders. We report here genome-wide association studies (GWAS) for six erythrocyte traits, including hemoglobin concentration (Hb), hematocrit (Hct), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and red blood cell count (RBC). We performed an initial GWAS in cohorts of the CHARGE Consortium totaling 24,167 individuals of European ancestry and replication in additional independent cohorts of the HaemGen Consortium totaling 9,456 individuals. We identified 23 loci significantly associated with these traits in a meta-analysis of the discovery and replication cohorts (combined P values ranging from 5 x 10(-8) to 7 x 10(-86)). Our findings include loci previously associated with these traits (HBS1L-MYB, HFE, TMPRSS6, TFR2, SPTA1) as well as new associations (EPO, TFRC, SH2B3 and 15 other loci). This study has identified new determinants of erythrocyte traits, offering insight into common variants underlying variation in erythrocyte measures.

Left ventricular size and shape: determinants of mechanical signal transduction pathways

Heart failure may be viewed as a progressive disorder that is impelled, at least in part, by progressive left ventricular (LV) remodeling. In the present discussion we will review the role of LV remodeling in the pathogenesis of heart failure, with a focus on the contribution that changes in LV size and shape play in the development and progression of the progression of heart failure. The clinical implication of this review is that existing neurohormonal strategies may not completely prevent disease progression in the failing heart, and that adjunctive strategies that are designed to specifically prevent and/or attenuate LV remodeling may play an important role in the clinical treatment of heart failure.

Haematologic determinants of left atrial spontaneous echo contrast in mitral stenosis

OBJECTIVES

To determine if a relationship exists in mitral stenosis, in patients with either sinus rhythm or atrial fibrillation, between left atrial spontaneous echo contrast and the haematologic indices haematocrit, red cell concentration, mean corpuscular volume, platelet count and volume.

METHODS

Left atrial spontaneous echo contrast severity was graded on a scale of 0-4 in 163 patients with symptomatic mitral stenosis (84 patients in sinus rhythm, 79 patients in atrial fibrillation) undergoing transesophageal echocardiography, cardiac catheterization and full blood examination as part of assessment prior to balloon mitral valvuloplasty.

RESULTS

In sinus rhythm, spontaneous echo contrast grade was negatively correlated with cardiac index (r=-0.33), mitral valve area (r=-0.25) and mitral regurgitation grade (r=-0.22) and positively correlated with haematocrit (r=0.24) and red cell concentration (r=0.25). Spontaneous echo contrast grade was not correlated with left atrial diameter or mean corpuscular volume. In atrial fibrillation, spontaneous echo contrast grade was also negatively correlated with mitral valve area (r=-0.25) and mitral regurgitation (r=-0.36) but was positively correlated with left atrial diameter (r=0.34) and was not correlated with cardiac index, haematocrit or red cell concentration. There was no correlation between spontaneous echo contrast grade and platelet variables in either group.

CONCLUSIONS

Natural variation in red cell concentration in patients with symptomatic mitral stenosis was an independent predictor of the severity of left atrial spontaneous echo contrast in sinus rhythm, but no relationship between red cell concentration and spontaneous echo contrast grade was evident in atrial fibrillation.

Inverse relation of haematocrit to cardiac index in mitral stenosis and atrial fibrillation

We investigated the relationship between atrial fibrillation and the red cell parameters haematocrit, red cell concentration and mean corpuscular volume in 95 female patients with mitral stenosis (mean age 51+/-11 years, 38 patients in atrial fibrillation, 57 patients in sinus rhythm) who had undergone full blood examination and right and left heart catheterisation. Haematocrit was a positive correlate of atrial fibrillation (r=0.29, p<0.009) and a negative correlate of cardiac index (r=-0.37, p<0.003), but cardiac index was the only independent correlate of haematocrit on multivariate analysis (r2=0.14). The mean corpuscular volume was a positive correlate of age (r=0.42, p<0.0001) and atrial fibrillation (r=0.29, p<0.005) and a negative correlate of cardiac index (r=-0.22, p<0.04) and red cell concentration (r=-0.56, p<0.0001). On multivariate analysis, however, only age and red cell concentration were independent correlates of mean corpuscular volume (r2=0.43). Cardiac index was inversely correlated with both haematocrit and red cell concentration in the subgroup of patients with atrial fibrillation but not those with sinus rhythm. This study demonstrates that the major determinant of the higher haematocrit in mitral stenosis patients with atrial fibrillation is an associated reduction in cardiac index.

The synergy of low lung function and low body mass index predicting all-cause mortality among older Japanese-American men

OBJECTIVE

To assess the joint characteristics of low standardized weight and compromised pulmonary function in predicting all-cause mortality.

DESIGN

A population-based, prospective cohort study.

SETTING

Oahu Island, Hawaii.

PARTICIPANTS

Surviving Japanese-American men of the Honolulu Heart Program cohort, 71 to 93 years of age (N = 3059).

MEASUREMENTS

Body mass index (BMI-weight in kilograms/square of height in meters) and 1-second forced expiratory volume (FEV1) as a percentage of age- and height-predicted FEV1 from the 1991 to 1993 examination of the cohort. Mortality data derived from the ongoing tracking of deaths of the cohort. Relations of selected risk factors among joint levels of BMI (< or = 21, > 21 to < 25, > or = 25 kg/m2) and percent predicted FEV1 (< or = 70%, > 70%) were determined. The impact of these covariates on relations between joint BMI/percent predicted FEV1 levels and subsequent all-cause mortality was assessed.

RESULTS

The highest age-adjusted mortality rate (91.9 deaths per 1000 person-years) was noted among men characterized by the joint conditions of percent predicted FEV1 < or = 70% and BMI < or = 21 kg/m2. This rate was 4.0 times the mortality rate of a "healthy" reference group characterized by percent predicted FEV1 > 70% and 21 < BMI < 25 kg/m2. This rate ratio is attenuated to 3.2 upon statistical control for measures of current and past smoking behavior. Among the three strata of BMI, statistical interaction is reflected in a heterogeneity of mortality rate differences (49.7, 21.8, -9.6 deaths/person-year, respectively) and rate ratios (2.18, 1.98, .66, respectively) comparing men with percent predicted FEV1 < or = 70% to > 70%.

CONCLUSION

Joint loss of pulmonary function and relative weight is predictive of subsequent all-cause mortality in excess of additive or multiplicative effects of each condition separately. Smoking behavior may contribute to this observation.