Association between inflammatory biomarkers of endothelial dysfunction and atherosclerosis in obesity

UVOD: Gojaznost je hronično, multifaktorijalno i kompleksno oboljenje povezano sa povećanim rizikom od aterosklerotskih kardiovaskularnih bolesti (KVB). Disfunkcija vaskularnog endotela predstavlja rani događaj u patofiziološkom kontinuumu aterosklerotskog procesa, a produženo izlaganje vaskularnog endotela faktorima rizika za aterosklerozu udruženim sa gojaznosti (insulinska rezistencija, dislipidemija, proinflamatorno/protrombozno stanje), može doprineti procesima aktivacije/disfunkcije endotela i progresiji ateroskleroze u supkliničku, odnosno kliničku formu bolesti. CILJ: Uporediti koncentracije solubilne forme adhezionih molekula – intracelularnog adhezivnog molekula –1 (sICAM–1) i E selektina (sE–selektin), između ispitanika sa hiperalimentacionim tipom gojaznosti i normalno uhranjenih zdravih ispitanika, kao i utvrditi eventualno postojanje razlika u koncentraciji sICAM–1 i sE–selektina između ispitanika kod kojih je merenjem debljine kompleksa intima medija karotidne arterije (IMK) uočen supklinički stadijum ateroskleroze i ispitanika koji imaju normalnu debljinu IMK. Ispitati povezanost parametara telesne kompozicije (ukupne masne mase tela i masne mase abdominalnih depoa), cirkulišućih koncentracija biomarkera disfunkcije vaskularnog endotela (sICAM–1 i sE–selektina) i IMK kod ispitanika sa hiperalimentacionim tipom gojaznosti. MATERIJAL I METODE: U istraživanje je uključeno 60 ispitanika sa hiperalimentacionim tipom gojaznosti bez pridruženih komorbiditeta i 30 zdravih normalno uhranjenih učesnika usklađenih sa ispitanicima po godinama života i polu koji su činili kontrolnu grupu. Svim ispitanicima su urađena antropometrijska merenja, analiza komponenata telesne kompozicije (bioelektrična impedansna analiza, Tanita Body Composition Analyzer BC – 418 MA III), laboratorijska analiza uzoraka krvi na automatizovanim analizatorskim sistemima sa određivanjem parametara metabolizma glukoze (bazalno i 2 h u toku oralnog glukoza tolerans testa), lipida i lipoproteina, inflamacije i homocisteina. Određivanje serumske koncentracije sICAM–1 i sE–selektina je vršeno ELISA tehnikom (R&D Systems, Inc. Minneapolis, USA). Vrednosti IMK–a su određivane pomoću karotidnog dupleks ultrazvuka (Aloka SSD–650 US system, Tokyo), a na osnovu izmerenih (IMK) i normalno očekivanih vrednosti IMK za svakog ispitanika je izračunavan IMK Z–skor. Supklinički stadijum ateroskleroze je definisan kao vrednost IMK Z–skora veća od 1 (što odgovara vrednosti IMK većoj od 95 percentila normalno očekivane vrednosti u odnosu na pol i godine života ispitanika). REZULTATI: Ispitanici sa hiperalimentacionim tipom gojaznosti su imali statistički značajno više vrednosti medijane serumske koncentracije sE–selektina u poređenju sa medijanom serumske koncetracije sE–selektina učesnika u kontrolnoj grupi (36,2 (33,21–43.7) vs. 25,14 (23,1–29,48) ng/mL, P=0,00). Gojazni ispitanici III stepena gojaznosti su imali statistički značajno višu medijanu serumske koncenracije sE–selektina u odnosu na medijanu sE–selektina u ispitanika I stepena gojaznosti (41,5 (36,58–49,48) vs. 34,34 (22,49–36,62) ng/mL, P=0,00), odnosno medijanu sE–selektina u ispitanika II stepena gojaznosti (41,5 (36,58–49,48) vs. 32,1 (26,1–43,64) ng/mL, P=0,00). Nije uočena statistički značajna razlika u medijani serumske koncentracije sE–selektina između ispitanika I i II stepena gojaznosti (34,34 (22,49–36,62) vs. 32,1 (26,1–43,64) ng/mL, P=0,12). Gojazni ispitanici su imali statistički značajno više vrednosti medijane serumske koncentracije sICAM–1 u poređenju sa medijanom serumske koncetracije sICAM–1 učesnika u kontrolnoj grupi (266,8 (245,8–326,73) vs.183,32 (167,9–208,57), P=0,00). U ispitivanoj grupi gojaznih uočena je statistički značajna razlika u medijani koncentracije sICAM–1 između ispitanika u I, II i III stepena gojaznosti (200,6 (190,26 - 264,4) vs. 278,5 (219,54 - 343,24) vs. 329,6 (259,2 - 350,34) ng/mL, P=0,00). Učestalost IMK Z–skor > 1 je bila statistički značajno eća u gojaznih ispitanika u odnosu na kontrolnu grupu (36/60 vs. 7/30, P=0,00). Ispitanici sa IMK Z–skor > 1 su imali statistički značajno višu medijanu koncentracije sICAM–1 u odnosu na ispitanike kod kojih je IMK Z–skor ≤ 1 (295,4 (238,46–340,38) vs. 244,2 (227,35–260,38), P=0.00). Regresionom analizom (R2=0,71, korigovani R2=0,59) je utvrđeno da su parametri hsCRP (β=0,45, P=0,00), HOMA–IR (β=0,44, P=0,035) i ISI (β=–0,36, P=0,028) nezavisno i statistički značajno povezani sa serumskom koncentracijom sE–selektina. Regresionom analizom (R2=0,65, korigovani R2=0,56) je utvrđeno da parametri ITM (β=0,55, P=0,00), trigliceridi (β=0,30, P=0,00), HDL holesterol (β=–0,31, P=0,00), odnos TG/HDL–holesterol (β=0,33, P=0,01), hsCRP (β=0,31, P=0,00) i fibrinogen (β=0,34, P=0,00) su nezavisno i statistički značajno povezani sa serumskom koncentracijom sICAM–1. U faktorskoj analizi je izdvojeno pet faktora “gojaznost”, “insulinska rezistencija”, “aterogeni faktor”, “endotelna disfunkcija i vaskularna inflamacija” i “metabolički faktor” koji objašnjavaju 69.72% ukupne varijanse ispitivanog uzorka. U multivarijabilnom modelu sa svim faktorima zajedno kojim je objašnjeno ukupno 75% varijanse, jedino je faktor gojaznost imao statički značajan i nezavistan uticaj na vrednost IMK Z–skor > 1 (OR=2,74 (CI 1,18–6,33), P=0,019). U faktoru gojaznost su se izdvojili parametri: FAT trunk (%), FAT (%), OS (cm), ITM (kg/m2), LDL – holesterol (mmol/L), SP (mmHg), HOMA1–%B, fibrinogen (g/L), ApoB/apoA-I i hsCRP (mg/L). Univarijantom logističkom regresijom je uočeno da porast u koncentraciji LDL–H (OR=5,33 (CI 1,9–14,2), P=0,02) i koncentraciji hsCRP–a (OR=2,53 (CI 1,3–3,98),P=0,017) povećava rizik za postojanje vrednosti IMK Z–skor > 1. ZAKLJUČAK: Cirkulišuće serumske koncentracije biomarkera disfunkcije vaskularnog endotela, sE–selektina i sICAM–1, su značajno više kod ispitanika sa hiperalimentacionim tipom gojaznosti u odnosu na njihove koncentracije u normalno uhranjenih ispitanika. U gojaznih ispitanika, koncentracija sE–selektina je povezana sa vrednostima indeksa insulinske rezistencije i biomarkera inflamacije, dok je koncentracija sICAM–1 značajno povezana sa udelom masne mase u ukupnoj telesnoj masi, vrednostima biomarkera inflamacije i proaterogenih lipidskih parametara. Ispitanici kod kojih postoji uvećanje abdominalnih masnih depoa i ukupnog udela masnog tkiva u telesnoj masi, vrednosti SKP, koncentracije LDL – holesterola, vrednosti lipoproteinskog indeksa ApoAI/apoB, bazalne insulinemije i biomarkera inflamacije, imaju trostruko povećan rizik od supkliničkog stadijuma ateroskleroze. U gojaznih osoba prilikom procene rizika od aterosklerotskih KVB, potrebno je utvrditi fenotipske osobine vaskularnog endotela i eventualno postojanje supkliničkog stadijuma ateroskleroze, da bi se definisale adekvatne preventivne mere i sagledale potencijalne terapijske mogućnosti.INTRODUCTION: Obesity is a chronic, multifactorial and complex disease associated with an increased risk of atherosclerotic cardiovascular diseases (CVD). Vascular endothelial dysfunction is an early event in the pathophysiological continuum of atherosclerotic process. The prolonged exposure of vascular endothelium to classical and obesity associated risk factors (insulin resistance, dyslipidemia, proinflammatory state) could further promote deterioration of endothelial function and progression of atherosclerosis to subclinical or clinical form of disease. OBJECTIVE: The aim of the study was to compare the concentration of soluble forms of adhesion molecules, intracellular adhesion molecule-1 (sICAM-1) and E-selectin (sE-selectin), between obese subjects and normal weight healthy subjects, as well as to determine the possible existence of differences in concentration of sICAM-1 and sE-selectin among subjects with subclinical stage of atherosclerosis (assessed by measuring the thickness of the intima media complex of the carotid artery (IMT)), and subjects who have a normal value of IMT. Also, the aim was to determine the association between the parameters of body composition (total body fat mass and fat mass intra-abdominal depots), circulating concentrations of sICAM-1 and sE-selectin, and value of IMT in obese subjects. MATERIALS AND METHODS: The study included 60 obese nondiabetic subjects, without preexisting CVD and other associated comorbidity, and 30 healthy normal weight age and sex matched participants. All subjects underwent anthropometric measurements, analysis of the components of body composition (bioelectrical impedance analysis, Tanita Body Composition Analyzer BC - 418 MA III), laboratory analysis of blood samples (automated analyzer systems) with determining the parameters of glucose metabolism (basal and 2 h during the oral glucose tolerance test), lipids and lipoproteins, inflammation and homocysteine. Serum concentrations of sICAM-1 and sE-selectin were determined by ELISA (R & D Systems, Inc., Minneapolis, USA). The values of IMK were determined by carotid duplex ultrasound (Aloka – ProSound ALPHA 10). IMK Z-score was calculated using the measured and the normal expected values of IMT for each patient. Subclinical stage of atherosclerosis was defined as the value of IMT Z-score greater than 1 (corresponding to the 95th sex-age-specific percentile of IMT measurements). RESULTS: Obese subjects had significantly higher median sE-selectin serum concentrations compared to median serum concentrations of sE-selectin in the normal weight subjects (36.2 (33.21-43.7) vs 25.14 (23.1-29.48) ng/mL, P=0.00). Morbid obesity subjects had significantly higher sE-selectin median serum concentration compared to the median sE-selectin concentration in moderate obese subjects (41.5 (36.58-49.48) vs 34.34 (22.49-36.62) ng/mL, P=0.00), and compared to the median sE-selectin concentration in severely obese subjects (41.5 (36.58-49.48) vs. 32.1 (26.1-4364) ng / mL, P=0.00). Obese subjects had significantly higher median sICAM-1 serum concentration compared to median sICAM-1 serum concentration in the control group (266.8 (245.8-326.73) vs. 183.32 (167.9-208.57), P=0.00). In the obese group, we observed a statistically significant difference in median sICAM-1 serum concentrations between moderate, severely and morbid obese subjects (200.6 (190.26-264.4) vs. 278.5 (219.54-343.24) vs. 329.6 (259.2-350.34) ng/mL, P=0.00). The frequency of IMT Z-score> 1 was significantly higher in the obese group compared to control group (36/60 vs. 7/30, P=0.00). Subjects with IMT Z-score> 1 had significantly higher median concentrations of sICAM-1 compared to those in which the IMK Z-score ≤ 1 (295.4 (238.46-340.38) vs. 244.2 ( 227.35-260.38), P=0.00). In regression analysis (R2=0.71, adjusted R2=0.59), hsCRP (β=0.45, P=0.00), HOMA-IR (β=0.44, P=0.035) and ISI (β=-0.36, P=0.028) were independently and significantly associated with serum sE-selectin concentration. In regression analysis (R2=0.65, adjusted R2=0.56), BMI (β=0.55, P=0.00), triglycerides (β=0.30, P=0.00), HDL cholesterol (β=-0.31, P=0.00), the ratio of TG/HDL-cholesterol ratio (β=0.33, P=0.01), hsCRP (β=0.31, P=0.00 ) and fibrinogen (β=0.34, P=0.00) were independently and significantly associated with serum sICAM-1 concentration. In the Factor analysis, five factors "obesity", "insulin resistance", "atherogenic factor," "endothelial dysfunction and vascular inflammation" and "metabolic factor" explained 69.72% of the total variance of the test sample. In a multivariate model with all the factors together (75% of the total variance), "obesity" factor was significantly and independently associated with IMT Z-score> 1 (OR=2.74 (CI 1.18-6.33), P=0.019). The "obesity" factor consisted of parameters: trunk fat (%), fat (%), waist (cm), BMI (kg/m2), LDL – cholesterol (mmol/L), systolic blood presure (mmHg), HOMA1-% B, fibrinogen (g/L), Apo B/apoA-I and hsCRP (mg/L). Logistic regression analysis showed that independent predictors of IMT Z-score> 1 were LDL-cholesterol (OR=5.33(CI 1.9-14.2), P=0.02) and hsCRP (OR=2.53 (CI 1.3-3.98), P=0.017). CONCLUSION: Circulating serum concentrations of endothelial dysfunction biomarkers, sE-selectin and sICAM-1, were significantly higher in obese subjects compared to concentration in the normal weight subjects. In obese subjects, the concentration of sE-selectin was associated with insulin resistance and biomarkers of inflammation, whereas sICAM-1 concentration was associated with fat mass, inflammation biomarkers and the proatherogenic lipid parametars. In individuals with increased abdominal fat depots and total proportion of fat mass in the body weight, values of SBP, LDL-C, ApoB/apoA-I, basal insulin levels and biomarkers of inflammation, there is threefold increased risk of subclinical stages of atherosclerosis. In order to define an adequate preventive measures and possible therapeutic options for atherosclerotic CVD in obese subjects, it is necessary to assess the phenotypic characteristics of vascular endothelium and possible presence of subclinical stage of atherosclerosis