Association between ambulatory saliva cortisol levels and plasma levels of matrix metalloproteinase-9 in a normal population

• Background: Psychosocial strain has been demonstrated to be a risk factor for coronary artery disease (CAD) and also to be associated with a dysfunctional HPA-axis. Based on a proposal on cortisol resistance in maladaptive monocytes as a potential mechanism linking psychosocial strain with CAD, this study aimed at testing the association between levels of salivary cortisol and matrix metalloproteinase-9 (MMP-9) in a normal population. Methods: 359 participants (50 % women) aged 45-69 were enrolled to this study, randomly drawn from a normal population in Sweden. Saliva samples were collected thrice per day (at awakening, 30 minutes after awakening, and just before going to bed) during three consecutive days. Cortisol levels at awakening and 30 minutes after awakening were used to estimate the diurnal peak. Cortisol was analyzed using a radioimmunoassay method. MMP-9 was measured in plasma using an ELISA-method. Results: After adjustment for age and sex, significant trends regarding MMP-9 were found both for cortisol peak quintiles (beta +1.9 ng/mL per quintile, p=0.029) and cortisol evening values (beta +2.1 ng/ml per quintile, p=0.017). These findings were consistent in regressions either excluding participants with known diagnoses of myocardial infarction, angina pectoris, rheumatoid arthritis, diabetes, cancer with ongoing treatment, chronic obstructive lung disease, osteoporosis and hypothyroidism, or adjusting for these diseases, also after adjustment for cardiovascular risk factors. Conclusions: The associations found between cortisol levels and MMP-9 in a normal population hint at a potential pathway linking prolonged psychosocial strain with cardiovascular events.

Nyckelord

Cardiovascular

cortisol

HPA‐axis

metalloproteinases

inflammation

MEDICINE

MEDICIN

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vet (ämneskategori)

ovr (ämneskategori)