L’étude des marqueurs biologiques dans la broncho-pneumopathie chronique obstructive (BPCO) et l'asthme, deux maladies respiratoires chroniques affectant des millions de personnes dans le monde, pourrait améliorer leur diagnostic, leur traitement et leur prévention.Cette thèse comprend deux parties. La première visait à évaluer l'association entre un marqueur spécifique des poumons, la protéine surfactant D (SP-D) sérique, et la BPCO, et à trouver un seuil de SP-D capable de discriminer les patients BPCO des témoins. Elle a été réalisée dans le cadre d’une étude cas-témoin au Liban incluant des patients BPCO (n=90), des asthmatiques (n=124) et des témoins (n=180). La deuxième partie visait à évaluer les associations chez les adultes des marqueurs de l’inflammation systémique (protéine C-réactive ultra-sensible, hs-CRP (n=252), et des cytokines (n=283)) et des marqueurs de dommages dus au stress oxydant (8-isoprostanes 8-IsoPs (n=258) du condensat de l’air exhalé) avec les phénotypes de l’asthme.Elle a été réalisée dans le cadre de l'étude épidémiologique longitudinale Française des facteurs génétiques et environnementaux de l'asthme (EGEA).Les résultats ont montré que les niveaux de SP-D sériques étaient associés positivement avec la BPCO et des seuils des niveaux de SP-D chez ces patients ont été identifiés avec d'excellentes valeurs discriminantes. Dans EGEA, aucune association n'a été trouvée entre les niveaux de hs-CRP sériques et le contrôle de l’asthme. Des profils de cytokines sériques (identifiés par analyse en composante principale) avec des niveaux élevés d’interleukine(IL)-1Ra et d’IL-10 ont été associés avec moins de crises d'asthme et un risque plus faible d'un mauvais contrôle de l'asthme sept ans plus tard. Les résultats des analyses préliminaires sur les associations entre les niveaux de 8-IsoPs et les phénotypes de l'asthme sont également présentés.Globalement, ces résultats ont montré l'utilité d'étudier les marqueurs biologiques en lien avec la BPCO et l'asthme. / Studying the biological markers in chronic obstructive pulmonary disease (COPD) and asthma, two chronic respiratory diseases affecting millions of individuals around the world, could improve their diagnosis, their treatment and their prevention.This thesis includes two parts. The first aimed to assess the association between a lung-specific biomarker, serum Surfactant Protein D (SP-D), and COPD, and to find cut-off points able to discriminate COPD patients from controls using SP-D levels. It was performed in a case-control study in Lebanon including COPD (n=90) and asthma patients (n=124) and controls (n=180). The second part aimed to assess the cross-sectional and longitudinal associations in adults for systemic inflammatory biomarkers (high sensitivity C reactive protein hs-CRP (n=252) and cytokines (n=283) as well as biomarkers of damage due to oxidative stress (8-Isoprostanes 8-IsoPs (n=258) from the exhaled breath condensate) and asthma outcomes.It was performed in the French longitudinal epidemiological study on the genetics and environmental factors of asthma (EGEA).Results showed that serum SP-D levels were positively associated with COPD and thresholds for SP-D levels in these patients were identified with excellent discriminant values. In EGEA, no association was found between serum hs-CRP levels and asthma control. Serum cytokine profiles (identified by principal component analysis) with high levels of interleukin (IL)-1Ra and IL-10 were associated with less asthma attacks and lower risk of poor asthma control in adults seven years later. The results of the preliminary analyses on the associations between the levels of 8-IsoPs and asthma outcomes are also presented.Overall, these results have shown the usefulness of studying the biological markers related to COPD and asthma.

Thesis (M.Sc. (Physiology))--North-West University, Potchefstroom Campus, 2009.

Thesis (M.Sc. (Physiology))--North-West University, Potchefstroom Campus, 2009.

B. Tech. (Department of Biotechnology, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Cardiovascular diseases (CVDs) are the leading cause of death worldwide, and the prevalence thereof is on the rise in developing countries due to the demographic transition and urbanization. The inflammatory process, atherosclerosis, is at the root of the majority of CVDs and is caused by unresolved inflammation. Various cardiovascular risk factors such as hyperglycaemia, dyslipidaemia, hypertension, smoking and aging stimulate the development of atherosclerosis through triggering inflammation. Being in a state of chronic low-grade inflammation therefor places an individual at higher risk of developing CVD, with inflammation playing a cause and effect role. The aim of this study was to investigate the inflammatory status of an elderly black South African population by analysis of inflammatory markers HS-CRP, TNF-α and IL-6, as well as the genetic polymorphism C174G associated with increased serum levels of IL-6 in some populations. The research was conducted in the field of Biomedical Sciences as a quantitative, cross-sectional, analytical observational design. The study was ethically approved and involved collection of 84 blood samples from volunteers in a purposively selected population as part of a larger collaborative study. Serum was used to analyse HS-CRP, TNF-α and IL-6 and DNA was extracted from whole blood for analysis of the C174G polymorphism. The median serum HS-CRP of 6.44mg/L (IQR = 2.82 - 9.86mg/L) fell within the highest risk (>5mg/L) of CVD and 75% of participants were at high (3.01-5mg/L) or very high (>5mg/L) risk. The median TNF-α of 0.00pg/mL was within the normal range and only 2.6% of participants had high serum TNF-α levels. The median serum IL-6 level was 1.92pg/mL and was also within the normal range with only 2.6% of participants who had high serum IL-6 levels. For the C174G polymorphism analysis, 98.6% had the GG, 1.4% the GC genotype and no participants had the CC genotype. The median serum IL-6 level of the homozygous GG group was 6.51mg/L, higher than the 4.13mg/L serum IL-6 of the heterozygous GC group. The difference in IL-6 should be considered with caution as only one participant had the C allele. A highly significant (p=0.001) correlation was found between HS-CRP and IL-6, as well as between IL-6 and TNF-α (p = 0.048). The elderly black Sharpeville community is in an increased inflammatory state which puts them at risk of CVD. The prevalence of the C allele in the C174G polymorphism is low in this population. Further research could be conducted as intervention studies to decrease the inflammatory state of the population and influence health policy changes to improve prevention of CVD.