Biomarker analysis by fluorokine multianalyte profiling distinguishes patients requiring intervention from patients with long-term quiescent coronary artery disease: a potential approach to identify atherosclerotic disease progression

Heparin Dosing During Percutaneous Coronary Intervention and Obesity

ABSTRACT

Unfractionated heparin is the most common anticoagulant used during percutaneous coronary intervention. Practice guidelines recommend an initial weight-based heparin bolus dose between 70 and 100 U/kg to achieve target activated clotting time (ACT) of 250-300 seconds. The impact of severe obesity on weight-based heparin dosing is not well studied. We performed a retrospective analysis of 424 patients undergoing percutaneous coronary intervention who received heparin for anticoagulation. We collected detailed data on cumulative heparin administration and measured ACT values in this cohort. We performed separate analyses to identify clinical predictors that may affect dose-response curves. There was significant variability in dosing with mean dose of 103.9 ± 32-U/kg heparin administered to achieve target ACT ≥ 250 seconds. Women received higher initial heparin doses when adjusted for weight than men (97.6 ± 31 vs. 89 ± 28 U/kg, P = 0.004), and only 49% of patients achieved ACT ≥ 250 s with the initial recommended heparin bolus dose (70-100 U/kg). Lower heparin dose (U/kg) was required in obese patients to achieve target ACT. In multivariate linear regression analysis with ACT as dependent variable, after inclusion of weight-based dosing for heparin, body mass index was the only significant covariate. In conclusion, there is significant variability in the therapeutic effect of heparin, with a lower weight-adjusted heparin dose required in obese patients.

Exploring the role of extracellular matrix proteins to develop biomarkers of plaque vulnerability and outcome

Cardiovascular disease (CVD) is the most common cause of death in industrialized countries. One underlying cause is atherosclerosis, which is a systemic disease characterized by plaques of retained lipids, inflammatory cells, apoptotic cells, calcium and extracellular matrix (ECM) proteins in the arterial wall. The biologic composition of an atherosclerotic plaque determines whether the plaque is more or less vulnerable, that is prone to rupture or erosion. Here, the ECM and tissue repair play an important role in plaque stability, vulnerability and progression. This review will focus on ECM remodelling in atherosclerotic plaques, with focus on how ECM biomarkers might predict plaque vulnerability and outcome.

Low Blood Content of IL-10-Producing CD4+ T Cells as a Risk Factor for Progression of Coronary Atherosclerosis

In a 2-year prospective study, prognostic significance of the blood content of IL-10-producing CD4⁺ T lymphocytes for progression of coronary artery atherosclerosis was assessed. Patients with verified stable angina (n=36) admitted for scheduled coronary angiography and coronary stenting were enrolled. The blood levels of CD4⁺FoxpP3⁺ Treg, CD4⁺IFNγ⁺ Th1, CD4⁺IL17⁺ Th17, CD4⁺IL10⁺ cells, sCD25, IL-10, IL-17, C-reactive protein, and lipoprotein (a) were assayed before endovascular interventions. The blood content of CD4⁺IL10⁺ T cells below 3.3% was associated with progression of coronary artery atherosclerosis (OR 12.0 (2.3, 61.0), sensitivity 77%, specificity 78%, p=0.003). No differences in other immunological parameters and common atherosclerosis risk factors in the groups were revealed. We hypothesize that the content of CD4⁺IL10⁺ T cells can be an important predictive marker for the progression of coronary atherosclerosis.

Plasma Proteomics Biomarkers in Alzheimer's Disease: Latest Advances and Challenges

The recent paradigm shift towards a more biologically oriented definition of Alzheimer's disease (AD) in clinical settings increases the need for sensitive biomarkers that can be applied in population-based settings. Blood plasma is easily accessible and contains a large number of proteins related to cerebral processes. It is therefore an ideal candidate for AD biomarker discovery. The present chapter provides an overview of the current research landscape in relation to blood-based AD biomarkers. Both clinical and methodological issues are covered. A brief summary is given on two relevant laboratory techniques to ascertain blood biomarker changes due to AD; methodological and clinical challenges in the field are also discussed.

Unbiased approaches to biomarker discovery in neurodegenerative diseases

Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and frontotemporal dementia have several important features in common. They are progressive, they affect a relatively inaccessible organ, and we have no disease-modifying therapies for them. For these brain-based diseases, current diagnosis and evaluation of disease severity rely almost entirely on clinical examination, which may be only a rough approximation of disease state. Thus, the development of biomarkers-objective, relatively easily measured, and precise indicators of pathogenic processes-could improve patient care and accelerate therapeutic discovery. Yet existing, rigorously tested neurodegenerative disease biomarkers are few, and even fewer biomarkers have translated into clinical use. To find new biomarkers for these diseases, an unbiased, high-throughput screening approach may be needed. In this review, I will describe the potential utility of such an approach to biomarker discovery, using Parkinson's disease as a case example.

Antibody-based proteomics and biomarker research - current status and limitations

Antibody-based proteomics play a very important role in biomarker discovery and validation, facilitating the high-throughput evaluation of candidate markers. Most proteomics-driven discovery is nowadays based on the use of MS. MS has many advantages, including its suitability for hypothesis-free biomarker discovery, since information on protein content of a sample is not required prior to analysis. However, MS presents one main caveat which is the limited sensitivity in complex samples, especially for body fluids, where protein expression covers a huge dynamic range. Antibody-based technologies remain the main solution to address this challenge since they reach higher sensitivity. In this article, we review the benefits and limitations of antibody-based proteomics in preclinical and clinical biomarker research for discovery and validation in body fluids and tissue. The combination of antibodies and MS, utilizing the best of both worlds, opens new avenues in biomarker research.

The CCR5 chemokine receptor mediates vasoconstriction and stimulates intimal hyperplasia in human vessels in vitro

AIMS

The chemokine receptor CCR5 and its inflammatory ligands have been linked to atherosclerosis, an accelerated form of which occurs in saphenous vein graft disease. We investigated the function of vascular smooth muscle CCR5 in human coronary artery and saphenous vein, vascular tissues susceptible to atherosclerosis, and vasospasm.

METHODS AND RESULTS

CCR5 ligands were vasoconstrictors in saphenous vein and coronary artery. In vein, constrictor responses to CCL4 were completely blocked by CCR5 antagonists, including maraviroc. CCR5 antagonists prevented the development of a neointima after 14 days in cultured saphenous vein. CCR5 and its ligands were expressed in normal and diseased coronary artery and saphenous vein and localized to medial and intimal smooth muscle, endothelial, and inflammatory cells. [(125)I]-CCL4 bound to venous smooth muscle with KD = 1.15 ± 0.26 nmol/L and density of 22 ± 9 fmol mg(-1) protein.

CONCLUSIONS

Our data support a potential role for CCR5 in vasoconstriction and neointimal formation in vitro and imply that CCR5 chemokines may contribute to vascular remodelling and augmented vascular tone in human coronary artery and vein graft disease. The repurposing of maraviroc for the treatment of cardiovascular disease warrants further investigation.

Left atrial and right atrial deformation in patients with coronary artery disease: a velocity vector imaging-based study

Background

Impaired left ventricular (LV) function has been shown by strain rate (SR) imaging in patients with coronary artery disease (CAD). Our aim was to investigate global and regional, systolic and diastolic left atrial (LA) and right atrial (RA) longitudinal deformation in CAD using velocity vector imaging.

Methods

Echocardiographic and velocity vector imaging studies were performed in 20 patients with mild CAD, 40 patients with severe CAD and 25 controls. Maximal atrial volume, peak atrial longitudinal strain (ε_s) and SR during LV systole (SRs), SR during early LV filling (SRe) and late LV filling (SRa) were measured. Longitudinal strain during atrial contraction (ε_a) was obtained at the onset of P-wave on electrocardiography, and ε_a/ε_s was calculated.

Results

Longitudinal peak ε_s and SRs of LA showed decreased trend among CAD patients. The global and lateral LA SRe were prominently lower, while RA ε_a, SRa and ε_a/ε_s were prominently higher in 2 CAD groups than control group (P value <0.05). As compared with controls and patients with other single-vessel disease, LA SRa and ε_a/ε_s ratio were significantly increased among patients with exclusively left anterior descending coronary artery (LAD) stenosis (SRa 1.14±0.38 s⁻¹, 1.10±0.41 s⁻¹, 1.45±0.46 s⁻¹, P value<0.05; ε_a/ε_s 0.44±0.11, 0.44±0.20, 0.57±0.12, P value<0.01).

Conclusions

Apparently decreased SRe of LA and increased ε_a, SRa and ε_a/ε_s of RA were found in CAD patients with preserved LVEF and E/E' in gray zone. SRa and ε_a/ε_s of LA were found to significantly increase in those with LAD stenosis.

Identification of a biological signature for schizophrenia in serum

Biomarkers are now used in many areas of medicine but are still lacking for psychiatric conditions such as schizophrenia (SCZ). We have used a multiplex molecular profiling approach to measure serum concentrations of 181 proteins and small molecules in 250 first and recent onset SCZ, 35 major depressive disorder (MDD), 32 euthymic bipolar disorder (BPD), 45 Asperger syndrome and 280 control subjects. Preliminary analysis resulted in identification of a signature comprised of 34 analytes in a cohort of closely matched SCZ (n=71) and control (n=59) subjects. Partial least squares discriminant analysis using this signature gave a separation of 60-75% of SCZ subjects from controls across five independent cohorts. The same analysis also gave a separation of ~50% of MDD patients and 10-20% of BPD and Asperger syndrome subjects from controls. These results demonstrate for the first time that a biological signature for SCZ can be identified in blood serum. This study lays the groundwork for development of a diagnostic test that can be used as an aid for distinguishing SCZ subjects from healthy controls and from those affected by related psychiatric illnesses with overlapping symptoms.

Regulatory T cells and IL-10 levels are reduced in patients with vulnerable coronary plaques

BACKGROUND

Despite having a similar large extent of atherosclerotic coronary affliction, some patients suffer of recurrent cardiac events, whereas others remain asymptomatic.

HYPOTHESIS

We hypothesized the existence of a systemic "signature" that could distinguish "vulnerable" patients with preexisting coronary atherosclerosis from those having similar risk factors and atheromatous burden, but no history of clinically evident plaque rupture/erosion.

METHODS

Twenty three patients who had at least two prior myocardial infarctions ("vulnerable group") were matched in respect to their background and coronary atherosclerosis extent with twenty one patients without a history of previous myocardial infarction who underwent routine coronary angiography before valvular surgery. We studied a panel of cytokines, antibodies and hormones including IL-6, IL-10, IL-12, antibodies to β2 glycoprotein I (β2GPI), antibodies to oxidized-LDL, adiponectin and resistin, along with levels of circulating EPCs and Tregs.

RESULTS

A significantly higher level of Treg cells was present in the control (73.4%±4) than in the "vulnerable patient" group (62.2%±10.7), p<0.001. IL-10 level was also significantly higher in the control than in the vulnerable patients (2.6±1.2 pg/ml versus 0.9±0.1 pg/ml respectively, p=0.03). There was no significant difference in the circulating levels of the other cytokines, hormones or EPCs between the two groups.

CONCLUSION

Regulatory T cells and serum IL-10 may discriminate "vulnerable" versus stable patients and may have a protective role against plaque rupture in patients with coronary atherosclerosis.

Circulating levels of matrix metalloproteinase-9 and abdominal aortic pathology: from the Dallas Heart Study

Prior reports have associated increased circulating levels of matrix metalloproteinase-9 (MMP-9), an endopeptidase active in the extracellular matrix, with the formation and rupture of aortic aneurysms, raising the possibility that MMP-9 may be a useful diagnostic or therapeutic target for aortic pathology. However, associations between MMP-9 and pathological abdominal aortic phenotypes in the general population have not been reported. In the Dallas Heart Study, a population-based sample of Dallas County residents (n = 2304), we measured MMP-9 and performed magnetic resonance imaging (MRI) of the abdominal aorta, measuring aortic compliance, plaque, wall thickness and luminal diameter. After adjustment for traditional cardiac risk factors and body size, higher MMP-9 quartiles were independently associated with higher aortic wall thickness and larger luminal diameter (p < 0.0001 for each), but not abdominal aortic plaque (p = 0.08), coronary artery calcium (p = 0.20) or the aortic luminal diameter/aortic wall thickness ratio (p = 0.37), supporting the hypothesis that therapies targeting MMP-9 may affect the abdominal aortic wall and modify aortic pathology.

The role of energy metabolism dysfunction and oxidative stress in schizophrenia revealed by proteomics

Schizophrenia is a psychiatric illness that affects approximately 30 million people worldwide. Converging lines of evidence suggest that mitochondrial function may be compromised in this disorder, and this can lead to perturbations in calcium buffering, oxidative phosphorylation, increased production of reactive oxygen species, and apoptotic factors, which can, in turn, affect neuronal processes such as neurotransmitter synthesis and synaptic plasticity. Proteomics studies in brain and peripheral tissues of schizophrenia patients have provided considerable evidence and identified biomarker fingerprints corresponding to such pathways. Here we review the results of these studies with a focus on the biomarker pattern depicting alterations in energy metabolism and oxidative stress in this debilitating illness.

Chemokine receptor CCR5: from AIDS to atherosclerosis

There is increasing recognition of an important contribution of chemokines and their receptors in the pathology of atherosclerosis and related cardiovascular disease. The chemokine receptor CCR5 was initially known for its role as a co-receptor for HIV infection of macrophages and is the target of the recently approved CCR5 antagonist maraviroc. However, evidence is now emerging supporting a role for CCR5 and its ligands CCL3 (MIP-1α), CCL4 (MIP-1β) and CCL5 (RANTES) in the initiation and progression of atherosclerosis. Specifically, the CCR5 deletion polymorphism CCR5delta32, which confers resistance to HIV infection, has been associated with a reduced risk of cardiovascular disease and both CCR5 antagonism and gene deletion reduce atherosclerosis in mouse models of the disease. Antagonism of CCL5 has also been shown to reduce atherosclerotic burden in these animal models. Crucially, CCR5 and its ligands CCL3, CCL4 and CCL5 have been identified in human and mouse vasculature and have been detected in human atherosclerotic plaque. Not unexpectedly, CC chemokines have also been linked to saphenous vein graft disease, which shares similarity to native vessel atherosclerosis. Distinct roles for chemokine-receptor systems in atherogenesis have been proposed, with CCR5 likely to be critical in recruitment of monocytes to developing plaques. With an increased burden of cardiovascular disease observed in HIV-infected individuals, the potential cardiovascular-protective effects of drugs that target the CCR5 receptor warrant greater attention. The availability of clinically validated antagonists such as maraviroc currently provides an advantage for targeting of CCR5 over other chemokine receptors.

Application of speckle-tracking echocardiography in detecting coronary artery disease in patients with maintenance hemodialysis

BACKGROUND

Satisfactory and noninvasive diagnostic tools for coronary artery disease (CAD) are not available in hemodialysis patients. We aimed to elucidate a reliable tool to diagnose CAD in these patients.

METHODS

102 hemodialysis patients received 2D speckle-tracking echocardiography with left ventricular (LV) strain analysis and blood tests for cardiac troponin T, high-sensitive C-reactive protein, interleukin (IL)-6, and IL-18.

RESULTS

The levels of biomarkers did not differ between patients with and without CAD. The factors associated with CAD were decreased circumferential strain, decreased global longitudinal strain, and the number of LV segments with decreased longitudinal strain. Logistic regression analyses showed that the number of LV segments with decreased longitudinal strain, over 6 segments, was strongly associated with CAD in hemodialysis patients (OR 12.08, 95% CI 3.724-39.209).

CONCLUSIONS

The noninvasive modality of speckle-tracking echocardiography with strain analysis is efficient and objective for identifying CAD in hemodialysis patients.

The application of multiplexed assay systems for molecular diagnostics

For decades, the diagnosis of schizophrenia and other psychiatric disorders has relied on subjective assessments such as Diagnostic and Statistical Manual criteria. There is now increasing interest in the identification of altered molecular patterns in blood and other accessible body fluids that can be used to help identify, stratify, and monitor psychiatric patients. Since shorter periods of psychosis are associated with a better prognosis, an accurate molecular test may lead to early intervention and thereby improve patient outcomes. In addition, such a test would open up the possibility to stratify more accurately the disease and could represent a novel translational medicine tool, which is crucial for the discovery and development of more efficacious therapies.

Challenges of introducing new biomarker products for neuropsychiatric disorders into the market

There are many challenges associated with the discovery and development of serum-based biomarkers for psychiatric disorders such as schizophrenia. Here, we review these challenges from the point of view of psychiatrists, general practitioners, the regulatory agencies, and biomarker scientists. There is a general opinion in psychiatric medicine that improvements over the current subjective tests are essential. Despite this, there is a reluctance to accept that peripheral molecules can do the job any better. In addition, psychiatrists find it difficult to accept that peripheral molecules, such as those found in blood, can reflect what is happening in the brain. However, the regulatory health authorities now consider biomarkers as important for the future of drug development and have called for efforts to modernize methods, tools, and techniques for the purpose of developing more efficient and safer drugs. We also describe here the development of the first ever molecular blood test for schizophrenia, and its reception in the market place, as a case in point.

Biomarker discovery for Alzheimer's disease, frontotemporal lobar degeneration, and Parkinson's disease

Ante-mortem diagnosis of neurodegenerative disorders based on clinical features alone is associated with variable sensitivity and specificity, and biomarkers can potentially improve the accuracy of clinical diagnosis. In patients suspected of having Alzheimer's disease (AD), alterations in cerebrospinal fluid (CSF) biomarkers that reflect the neuropathologic changes of AD strongly support the diagnosis, although there is a trade-off between sensitivity and specificity due to similar changes in cognitively healthy subjects. Here, we review the current approaches in using CSF AD biomarkers (total tau, p-tau(181), and Abeta42) to predict the presence of AD pathology, and our recent work using multi-analyte profiling to derive novel biomarkers for biofluid-based AD diagnosis. We also review our use of the multi-analyte profiling strategy to identify novel biomarkers that can distinguish between subtypes of frontotemporal lobar degeneration, and those at risk of developing cognitive impairment in Parkinson's disease. Multi-analyte profiling is a powerful tool for biomarker discovery in complex neurodegenerative disorders, and analytes associated with one or more diseases may shed light on relevant biological pathways and potential targets for intervention.

Validation of a blood-based laboratory test to aid in the confirmation of a diagnosis of schizophrenia

We describe the validation of a serum-based test developed by Rules-Based Medicine which can be used to help confirm the diagnosis of schizophrenia. In preliminary studies using multiplex immunoassay profiling technology, we identified a disease signature comprised of 51 analytes which could distinguish schizophrenia (n = 250) from control (n = 230) subjects. In the next stage, these analytes were developed as a refined 51-plex immunoassay panel for validation using a large independent cohort of schizophrenia (n = 577) and control (n = 229) subjects. The resulting test yielded an overall sensitivity of 83% and specificity of 83% with a receiver operating characteristic area under the curve (ROC-AUC) of 89%. These 51 immunoassays and the associated decision rule delivered a sensitive and specific prediction for the presence of schizophrenia in patients compared to matched healthy controls.

Decreased C-reactive protein levels in Alzheimer disease

C-reactive protein (CRP) is an acute-phase reactant that has been found to be associated with Alzheimer disease (AD) in histopathological and longitudinal studies; however, little data exist regarding serum CRP levels in patients with established AD. The current study evaluated CRP levels in 192 patients diagnosed with probable AD (mean age = 75.8 +/- 8.2 years; 50% female) as compared to 174 nondemented controls (mean age = 70.6 +/- 8.2 years; 63% female). Mean CRP levels were found to be significantly decreased in AD (2.9 microg/mL) versus controls (4.9 microg/mL; P = .003). In adjusted models, elevated CRP significantly predicted poorer (elevated) Clinical Dementia Rating Scale sum of boxes (CDR SB) scores in patients with AD. In controls, CRP was negatively associated with Mini-Mental State Examination (MMSE) scores and positively associated with CDR SB scores. These findings, together with previously published results, are consistent with the hypothesis that midlife elevations in CRP are associated with increased risk of AD development though elevated CRP levels are not useful for prediction in the immediate prodrome years before AD becomes clinically manifest. However, for a subgroup of patients with AD, elevated CRP continues to predict increased dementia severity suggestive of a possible proinflammatory endophenotype in AD.

Inflammatory mediators and premature coronary atherosclerosis in rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is an inflammatory disease associated with premature atherosclerosis. We hypothesized that mediators of inflammation associated with atherosclerosis in other populations (interleukin-6 [IL-6], tumor necrosis factor alpha [TNFalpha], serum amyloid A [SAA], vascular endothelial growth factor, neutrophil count, IL-1alpha, E-selectin, intercellular adhesion molecule 1 [ICAM-1], myeloperoxidase [MPO], matrix metalloproteinase 9, and vascular cell adhesion molecule 1) would be increased and associated with the severity of coronary atherosclerosis in patients with RA.

METHODS

Clinical variables, concentrations of inflammatory mediators, and coronary artery calcification were measured in 169 patients with RA and 92 control subjects. Differences in concentrations of inflammatory mediators were compared using median quantile regression. The relationship of inflammatory mediators with the severity of coronary calcification in RA and control subjects was examined using proportional odds logistic regression, allowing for interaction with disease status. Models were adjusted for traditional cardiovascular risk factors.

RESULTS

Median serum concentrations of IL-6, SAA, ICAM-1, E-selectin, TNFalpha, and MPO and peripheral blood neutrophil count were higher in patients with RA than controls (all P < 0.05), independent of Framingham risk score and diabetes mellitus (DM). IL-6 (main effect odds ratio [OR] 1.72; 95% confidence interval [95% CI] 1.12, 2.66) and TNFalpha (main effect OR 1.49; 95% CI 1.16, 1.90) concentrations were significantly associated with higher amounts of coronary calcium, independent of Framingham risk score and DM, and such main effects significantly differed from controls (P = 0.001 and 0.03 for interaction, respectively).

CONCLUSION

TNFalpha and IL-6 are significantly associated with the severity of subclinical atherosclerosis, independent of Framingham risk score, in RA.

The role of proteomics in depression research

Depression is a severe neuropsychiatric disorder affecting approximately 10% of the world population. Despite this, the molecular mechanisms underlying the disorder are still not understood. Novel technologies such as proteomic-based platforms are beginning to offer new insights into this devastating illness, beyond those provided by the standard targeted methodologies. Here, we will show the potential of proteome analyses as a tool to elucidate the pathophysiological mechanisms of depression as well as the discovery of potential diagnostic, therapeutic and disease course biomarkers.

Brain-derived neurotrophic factor levels in Alzheimer's disease

The current search for biomarkers that are diagnostic and/or prognostic of Alzheimer's disease (AD) is of vital importance given the rapidly aging population. It was recently reported that brain-derived neurotrophic factor (BDNF) fluctuated according to AD severity, suggesting that BDNF might have utility for diagnostics and monitoring of therapeutic efficacy. The current study sought to examine whether BDNF levels varied according to AD severity, as previously reported. There were 196 participants (Probable AD, n = 98; Controls, n = 98) in the Texas Alzheimer's Research Consortium (TARC) Longitudinal Research Cohort available for analysis. BDNF levels were assayed via multiplex immunoassay. Regression analyses were utilized to examine the relation between BDNF levels, Mini-Mental Status Examination, and Clinical Dementia Rating scores adjusting for age and gender. In adjusted models, BDNF levels did not distinguish between AD patients and normal controls and did not significantly predict AD severity or global cognitive functioning. In conclusion, these findings do not support the notion that BDNF serves as a diagnostic marker for AD or disease severity. It is likely that the most accurate approach to identifying biomarkers of AD will be through an algorithmic approach that combines multiple markers reflective of various pathways.

Matrix metalloproteinase therapy in heart failure

Milestones in the progression to heart failure following myocardial infarction (MI) are changes in left ventricular (LV) geometry and function, termed post-MI remodeling. Critical to this adverse remodeling process are changes in the expression, synthesis, and degradation of myocardial extracellular matrix (ECM) proteins. The myocardial ECM is not a passive entity but a complex and dynamic microenvironment that represents an important structural and signaling system within the myocardium. In particular, basic and clinical studies have provided conclusive evidence that abnormal and persistent activation of the ECM degradation pathway, notably through the matrix metalloproteinases (MMPs), contribute to adverse post-MI remodeling. This review examines recent clinical studies that provide further support to the hypothesis that a specific portfolio of MMPs are diagnostic and likely contributory to LV remodeling and the progression to heart failure after MI. Future translational and clinical research focused on the molecular and cellular mechanisms regulating ECM structure and function likely will contribute to an improved understanding of post-MI LV remodeling and yield novel therapeutic targets.

Endothelial dysfunction and specific inflammation in obesity hypoventilation syndrome

Background

Obesity hypoventilation syndrome (OHS) is associated with increased cardiovascular morbidity. What moderate chronic hypoventilation adds to obesity on systemic inflammation and endothelial dysfunction remains unknown.

Question

To compare inflammatory status and endothelial function in OHS versus eucapnic obese patients.

Methodology

14 OHS and 39 eucapnic obese patients matched for BMI and age were compared. Diurnal blood gazes, overnight polysomnography and endothelial function, measured by reactive hyperemia peripheral arterial tonometry (RH-PAT), were assessed. Inflammatory (Leptin, RANTES, MCP-1, IL-6, IL-8, TNFα, Resistin) and anti-inflammatory (adiponectin, IL-1Ra) cytokines were measured by multiplex beads immunoassays.

Principal Findings

OHS exhibited a higher PaCO₂, a lower forced vital capacity (FVC) and tended to have a lower PaO₂ than eucapnic obese patients. _HS-CRP, RANTES levels and glycated haemoglobin (HbA1c) were significantly increased in OHS (respectively 11.1±10.9 vs. 5.7±5.5 mg.l⁻¹ for _HS-CRP, 55.9±55.3 vs 23.3±15.8 ng/ml for RANTES and 7.3±4.3 vs 6.1±1.7 for HbA1c). Serum adiponectin was reduced in OHS (7606±2977 vs 13660±7854 ng/ml). Endothelial function was significantly more impaired in OHS (RH-PAT index: 0.22±0.06 vs 0.51±0.11).

Conclusions

Compared to eucapnic obesity, OHS is associated with a specific increase in the pro-atherosclerotic RANTES chemokine, a decrease in the anti-inflammatory adipokine adiponectin and impaired endothelial function. These three conditions are known to be strongly associated with an increased cardiovascular risk.

Trial Registration

ClinicalTrials.gov NCT00603096