Autonomic and cerebrovascular abnormalities in mild COPD are worsened by chronic smoking

Abstract

Patients with chronic obstructive pulmonary disease (COPD) may develop hypercapnia and hypoxia, two main determinants of cerebral blood flow. The current authors tested whether cerebrovascular regulation was altered in mild COPD, modified by manoeuvres acutely improving autonomic cardiovascular modulation or influenced by smoking habit.In 15 eucapnic normoxic mild COPD patients (eight smokers) and 28 age-matched controls (14 smokers), midcerebral artery blood flow velocity (MCFV), end-tidal carbon dioxide tension (PET,CO 2 ), arterial oxygen saturation (Sa,O 2 ), ECG and blood pressure at rest were monitored during progressive hypercapnic hyperoxia, isocapnic hypoxia, slow breathing and oxygen administration. MCFV, arterial baroreflex and dynamic MCFV-blood pressure relationships were compared by phase analysis.COPD and control smokers showed higher MCFV (when corrected for PET,CO 2 ), lower cerebrovascular resistance index and lower sensitivity to hypercapnia than nonsmokers, with equal sensitivity to Sa,O 2 and similar phase analysis. Arterial baroreflex was depressed in all COPD patients. Slow breathing and oxygen administration improved baroreflex sensitivity and reduced MCFV in all COPD patients.Patients with mild chronic obstructive pulmonary disease show autonomic dysfunction. Chronic smoking induces cerebral vasodilation and impairs cerebrovascular control. All abnormalities can be partly corrected by improving the cardio-and cerebrovascular autonomic modulation, suggesting that functional autonomic abnormalities are already present at an early stage of disease.

Decreased cerebrovascular response to CO2in post-menopausal females with COPD: role of oxidative stress

“…In young adults, cerebrovascular deficiencies are only observed following acute smoking (after smoking for 1 min) [23]. Similarly, in a healthy older population, smoking status was not a significant factor in determining the sensitivity to hypercapnia [7]. Interestingly, in this same study, BERNARDI et al [7] found that individuals who were current smokers had mild COPD and significantly lower cerebrovascular sensitivity to hypercapnia compared with individuals who only had mild airflow obstruction, without a smoking history.…”

“…?mmHg -1 from a previously published study [7], we determined that to detect a significant difference in the cerebrovacular sensitivity to hypercapnia, each group would have to consist of 11 participants (using an unpaired two-tailed t-test and setting a at 0.05 and b at 0.80).…”

“…Recent literature suggests that cerebrovascular sensitivity and ventilatory response are tightly linked in healthy individuals [5]. However, evidence suggests that COPD patients exhibit cerebrovascular disturbances [3,6,7], although the pathological onset and cause of these disturbances have not yet been comprehensively studied.…”

“…While a few studies have looked at cerebrovascular health in COPD patients [3,6,7,11], no study has investigated how oxidative stress and antioxidant activity could be involved in the CBF regulation observed in COPD. Oestrogen is a sex hormone with beneficial vasoactive and antioxidant properties.…”

Cigarette smoke promotes genomic evolution in the periodontal pathogen Porphyromonas gingivalis.

“…Reduced serum levels of Immunoglobulin G (IgG), an important anti-microbial antibody, have been detected in smokers when compared to non-smokers [96,97]. T-cell proliferative responses have also shown to be suppressed in smokers.…”