Differences in Microsatellite DNA level between Asthma and COPD

¹ Research Lab of Molecular Pulmonology and
² Research Lab of Molecular Pulmonology and; and Dept of Thoracic Medicine, Medical School University of Crete, Heraklion Crete, Greece
³ Dept of Thoracic Medicine, Medical School University of Crete, Heraklion Crete, Greece
⁴ Dept of Respiratory Medicine, University of Athens Medical School, "Sotiria" Chest Diseases Hospital, Athens, Greece
⁵ Meakins-Christie Laboratories, McGill University, 3626 St. Urbain St. P.Q. Montreal, H2X2P2, Canada

^* To whom correspondence should be addressed. E-mail: siafak{at}med.uoc.gr.

	Abstract

Previous studies showed that Microsatellite DNA Instability (MSI) is detectable in sputum cells in COPD and Asthma. The aim of the present study was to investigate if Asthma and COPD could be distinguished at the Microsatellite (MS) DNA level.

DNA was extracted from sputum cells, and from white blood cells in 63 COPD patients, 60 non-COPD smokers, 36 Asthmatics and 30 healthy non-smokers. Ten microsatellite markers located on chromosomes 2p, 5q, 6p, 10q, 13q, 14q, 17q, were analyzed.

No MSI was detected in non-COPD smokers and in healthy non-smokers. Statistically significant higher proportion of COPD patients exhibited MSI (49.2%) compared with asthmatics (22.2%), p=0.01. MSI was detected even in the mild stages of COPD (33.3%) and asthma (22.2%). No relationship was found between MSI and the severity of COPD. The most frequently affected marker was D14S588 (17.5% in COPD and 2.7% in Asthma). D6S344, G29802 and D13S71 markers showed alterations only in COPD and G29802 was associated with significantly decreased FEV₁(% pred), (p=0.03), while MSI in D6S344 was associated with significantly higher FEV₁(%pred), (p=0.01).

The frequency of MSI was higher in COPD than in Asthma and MSI in three markers showed COPD specificity. However, further studies are needed to verify the differences between COPD and Asthma, at the MS level.

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