L’obésité est devenue un véritable problème de santé publique. Elle est fréquemment associée à plusieurs anomalies cardiométaboliques telles que l’hypertension artérielle, l’insulinorésistance et les dyslipidémies qui font le lit du diabète de type 2 et des maladies cardiovasculaires. Cependant la fréquence de ces anomalies varie considérablement parmi les sujets obèses faisant de cette maladie chronique une situation clinique très hétérogène. A ce titre un nouveau concept a émergé, impliquant une population de patients sans facteurs de risque apparents, appelé « obèse métaboliquement sain » ou « metabolically healthy obese » (MHO). Des efforts sont en cours pour comprendre les mécanismes sous-jacents à ce phénotype et ses conséquences à long terme. L’objectif principal de cette thèse était d’étudier le lien entre le phénotype MHO et diverses pathologies chroniques connues pour être associées à l’obésité. Les données provenant des cohortes Whitehall II et GAZEL ont été utilisées pour examiner les associations entre le phénotype MHO et la mortalité, les maladies cardiovasculaires, le diabète de type 2 et la dépression. En comparaison aux sujets de poids normal métaboliquement sains, les individus MHO ont un risque accru de mortalité globale et cardiovasculaire, de diabète de type 2 et de maladies cardiovasculaires mais pas de dépression. Comparés aux sujets obèses avec anomalies métaboliques, les individus MHO ont un risque similaire de mortalité et de maladies cardiovasculaires, mais un moindre risque de diabète de type 2 et dépression. Nos résultats suggèrent que l’obésité à profil cardiométabolique normal n’est pas une condition bénigne. Une meilleure compréhension de ce phénotype contribuera à améliorer la décision thérapeutique et aidera peut-être à identifier des cibles thérapeutiques nouvelles. / Obesity has become a major public health concern. It is frequently associated with several cardiometabolic abnormalities such as hypertension, insulin resistance and dyslipidemia leading to type 2 diabetes and cardiovascular disease. However, the frequency of these abnormalities varies widely among obese subjects, making this chronic condition a very heterogeneous clinical situation. As such a new concept has emerged, involving a population of patients without metabolic risk, called "metabolically healthy obese" (MHO). Intense interest surrounds the MHO phenotype with on-going efforts to understand the mechanisms underlying this phenotype and its long-term consequences. The main objective of this thesis was to study the relationship between the MHO phenotype and various chronic diseases known to be associated with obesity. Data from the Whitehall II and GAZEL cohorts were used to examine associations between this phenotype and mortality, cardiovascular diseases, type 2 diabetes, and depression. Compared to metabolically healthy normal weight subjects, MHO individuals have an increased risk of overall and cardiovascular mortality, type 2 diabetes and cardiovascular diseases, but not depression. Compared to metabolically unhealthy obese subjects, MHO individuals have a similar risk of mortality and cardiovascular disease, but a lower risk of type 2 diabetes, and depression. Our results suggest that obesity with normal cardiometabolic profile is not a benign condition. A better understanding of this phenotype will enhance therapeutic decision making and possibly help to identify new therapeutic targets.

<p>Izvod: UVOD: Metabolički zdrave gojazne osobe su okarakterisane odsustvom metaboličkog sindroma i/ili insulinske rezistencije i sistemske inflamacije. Mali je broj podataka o ulozi aktivnosti autonomnog nervnog sistema u razvoju kardiometaboličkih komplikacija kod gojaznih osoba, kao i o njegovoj vezi sa specifičnom distribucijom masnog tkiva. CILJ: Analiza varijabilnost srčane frekvencije (HRV) kod metabolički zdravih (MHO) i gojaznih osoba sa metaboličkim rizikom (MUO), analiza povezanosti HRV sa metaboličkim faktorima i distribucijom masnog tkiva, kao i analiza uzrasne dinamike HRV kod gojaznih osoba različitih kardiometaboličkih profila. MATERIJAL I METODE: Ukupno 125 gojaznih ispitanika oba pola podvrgnuto je antropometrijskim merenjima u cilju procene mase i distribucije masnog tkiva, izvr&scaron;ena je analiza telesne kompozicije, uzeti su uzorci krvi u cilju određivanja lipidskog i lipoproteinskog statusa, stanja glikoregulacije i nivoa inflamatornih markera, meren je krvni pritisak i procenjena je HRV tokom petominutne digitalne elektrokardiografije. Podaci su statistički obrađeni kori&scaron;ćenjem paketa SPSS 11.5. REZULTATI: HRV mere se nisu razlikovale statistički značajno među MHO i MUO mu&scaron;karcima. MHO žene su imale vi&scaron;e vrednosti RRNN, SDNN, RMSSD, pNN50, LF, HF i TP u odnosu na MUO žene, na čega metabolički profil utiče sa 6,6-11,2%(p˂0,01), predstavljeno kroz parcijalnu deljenu varijansu. Nakon antropometrijskih faktora uzetih u obzir, perzistirale su vi&scaron;e vrednosti HF kod MHO žena. Razlika u RRNN, pNN50 i TP između MHO i MUO premenopauzalnih žena (vi&scaron;e vrednosti za MHO, p˂0,05) se izgubila nakon kontrole za krvni pritisak. Insulinemija je uticala na pojave razlika u RRNN između MHO i MUO premenopauzalnih žena, parcijalna deljena varijansa 7,6%. SAD kod žena se negativno povezivao sa LF/HF i LFnorm, a pozitivno sa HFnorm, parcijalne deljene varijanse 8,4-11,9% (p˂0,05). Prednji nabor podlaktice kod žena se pozitivno povezivao sa LF i LF/HF, a negativno sa HFnorm (p˂0,01). Visceralna masna masa je predviđala značajno HRV mere mu&scaron;karaca, parcijalna deljena varijansa 13-34% (p˂0,01). U okviru gornjeg tercila HRV mera RMSSD, pNN50 i LF MUO osoba, HOMA indeks je statistički značajno niži (p˂0,05). Kod MUO osoba SDNN, RMSSD, lnpNN50, lnLF, lnHF i TP značajno su se smanjivali u uzrastu od 19-29 do 40-49 godina. Kod MHO osoba primetna je uzrasna promena HF mere u četvrtoj deceniji života. ZAKLJUČAK: MHO osobe ženskog pola imaju značajno vi&scaron;e vrednosti markera varijabilnosti srčane frekvencije u odnosu na MUO. Razlike u HRV merama su uslovljene kriterijumima metaboličke podele, predominantno insulinemijom, vrednostima krvnog pritiska i centralnom masnom masom. Kod žena centralna distribucija masnog tkiva korelira sa smanjenom srčanom simpatičkom aktivno&scaron;ću dok se periferna distribucija masnog tkiva povezuje obrnuto sa komponentama aktivnosti autonomnog nervnog sistema. Kod mu&scaron;karaca centralna masna masa, ali ne i periferna, je značajno povezana sa HRV. MUO osobe sa nižom HRV imaju veći stepen insulinske rezistencije, dok HRV ne utiče na insulinsku senzitivnost MHO osoba. Značajniji uzrasno zavisni pad HRV mera primetan je kod MUO osoba, pogađajući obe komponente autonomnog nervnog sistema za razliku od MHO osoba.</p> / <p>Abstract: INTRODUCTION: Metabolically healthy obese (MHO) individuals are characterized by absence of metabolic syndrome and/or insulin resistance and inflammation. Little is known about the role of autonomic nervous system in development of cardiometabolic complications in obese people and about its influence on the specific adipose tissue distribution. AIM: Analysis of the hearth rate variability (HRV) in metabolically healthy (MHO) and unhealthy (MUO) obese people, its connection with adipose tissue distribution, and age dependent dynamics of HRV. MATERIAL AND METHODS: A total of 125 obese patients of both sexes underwent anthropometric measurements in order to assess adipose tissue mass and distribution, body composition was assessed, blood samples were taken in order to analyze parameters of lipid and lipoprotein profile, condition of glycoregulation and inflammatory markers, blood pressure was measured and short term HRV was conducted. Data were statisticaly analyzed using SPSS 11.5. RESULTS: HRV measures did not differ significantly between MHO and MUO men. MHO women had higher values of RRNN, SDNN, RMSSD, pNN50, LF, HF and TP compared to the MUO women, influence of metabolic profile was 6,6-11,2% (p˂0,01), presented through partial shared variance. After controlling for anthropometric factors higher HF persisted in MHO women. Differences in RRNN, pNN50 and TP between MHO and MUO premenopausal women (higher values of MHO, p˂0,05) were lost after controlling for blood pressure. Insulinemia influenced the difference in RRNN between MHO and MUO premenopausal women, partial shared variance 7,6%. SAD in women was connected negatively with the LF/HF and LFnorm, and positively with HFnorm, partial shared variance 8,4-11,9% (p˂0,05). Anterior forearm skinfold in women correlated positively with LF and LF/HF, and negatively with HFnorm (p˂0,01). Visceral fat mass predicted significantly HRV in men, partial shared variance 13-34% (p˂0,01). Within the upper tertile of HRV measures RMSSD, pNN50 and LF in MUO people, HOMA was significantly lower (p˂0,05). In MUO SDNN, RMSSD, lnpNN50, lnLF,lnHF and TP significantly decreased in the period from 19-29 to 40-49 years. In MHO people the change in HF was noticeable in the fourth decade of life. CONCLUSION: MHO women have significantly higher levels of HRV markers comparing to the MUO. The differences in HRV measures are influenced by metabolic criteria used, predominantly by insulinemia, blood pressure and central fat mass. In women, central distribution of adipose tissue correlates with reduced cardiac sympathetic activity, while the connection of peripheral fat mass distribution with components of autonomic nervuos system activity is reverse. In men, central fat mass, but not peripheral, is significantly associated with HRV. MUO people with lower HRV have a higher degree of insulin resistance, while the level of HRV measures does not affect insulin sensitivity in MHO individuals. Significant age-dependent decrease in both ANS representatives of HRV measures was noticed in MUO people, unlike MHO individuals.</p>