[Correlation of reticular basement membrane thickness and airway wall remolding in asthma patients]

To investigate the correlation between the reticular basement membrane thickness and the airway wall remolding in asthma patients.

Lung tissues were obtained from 5 patients who died from asthma, 3 males and 2 females, aged 45 +/- 16 (fatal asthma group), 5 asthmatics who died of diseases unrelated to asthma, 3 males and 2 females, aged 47 +/- 13, (non-fatal asthma group), and 5 dead patients without asthma, 3 males and 2 females, aged 24 +/- 14 (control group) to select 41, 38, and 43 transverse sections of tracheae respectively. The samples of tracheae were divided into cartilaginous and membranous airways by light microscopy (x100). The thickness of reticular basement membrane and the dimensions of the airway wall, including the smooth muscle area, submucosal gland area, inner and outer wall areas, and lumen area were measured. The correlations of reticular basement membrane thickness with the airway changes were analyzed.

The reticular basement membrane was significantly thicker in both cartilaginous and membranous airways in the fatal and non-fatal asthma groups than in the control group (all P < 0.05). The submucosal gland area of the fatal asthma group was significantly larger than those of the non-fatal asthma group and control group (both P < 0.05). The inner wall area of the cartilaginous airway of the fatal asthma group was significantly larger than that of the non-fatal asthma group (P < 0.05); however, the inner wall area of the membranous airway of the fatal asthma group was not significantly different from that of the non-fatal asthma group. The outer wall areas of cartilaginous and membranous airways of the fatal asthma group were both significantly larger than those of the other 2 groups (all P < 0.05). There was no significant difference in the lumen areas of cartilaginous and membranous airways between the fatal and non-fatal asthma groups. The reticular basement membrane thickness was correlated with the smooth muscle area (P < 0.05), submucosal gland area (P < 0.05), and inner wall area (P < 0.01) of the corresponding bronchi in regard to the cartilaginous airway; and was correlated with the smooth muscle area (P < 0.05) and inner wall area (P < 0.01) of the corresponding bronchi in regard to the membranous airway, but was not correlated with the airway size, lumen area, and outer wall area in regard to the 2 kinds of airways.

The reticular basement membrane thickness of central airway reflects the airway remolding of the central airway and the changes of smooth muscle and inner wall of the peripheral airway. It is worthwhile to do end bronchial biopsy to measure the reticular basement membrane thickness so as to assess the pathology of the airway and to conduct long-term follow-up among the asthma patients.