Obesity increases the likelihood of diseases and conditions associated with increased mortality. Recently, there has been an active growth of scientific interest in the role of obesity as a comorbid disease in patients with chronic obstructive pulmonary diseases (COPD). However, the immunological, ultrastructural, pathomorphological, histochemical, and immunohistochemical features of comorbid pathology of the respiratory organs in obese persons remain insufficiently studied.
Within the work, a retrospective study of 11149 autopsy cases for the last decade (2013–2022) was conducted based on the Lviv Regional Pathological Anatomical Bureau. 970 autopsy cases (8.7% of the total sample) of obese deceased were included in the retrospective study using the continuous sample method.
The prospective study included the analysis of 60 autopsy cases. Two research groups were formed: group 1 (control group, n=30) consisted of deceased with normal body weight and group 2 (n=30) - deceased with obesity.
A sample of 120 animals was included in the experimental study. Four groups of animals were formed by a blind method: a control group (CL group, n=30) – animals were fed according to a standard diet; a group of rats exposed to tobacco smoking without simulated obesity (group S, n=30) - standard diet with exposure in a chamber with tobacco smoke for 4 minutes twice a day, five days a week; a group of rats with experimental obesity (group O, n=30) with a high-fat diet; a group of rats with experimental obesity exposed to tobacco smoking (OS group, n=30).
According to the results of a retrospective analysis, obesity was registered almost twice as often in women than in men. The average age of deceased women (67.2±0.5 years) was significantly (p<0.001) higher than that of men (62.5±0.4 years). In the structure of the main causes of death in obese people, the main share was taken by the diseases of the circulatory system - 41.1±1.5% (439 cases) and infectious diseases - 23.6±1.3%, (252 cases). Among the accompanying causes of death in obese persons, as in the case of the main causes, circulatory system diseases were also most often registered - 42.4±1.0% (955 cases) and also diseases of the respiratory system - 27.8±0.9% (626 cases).
The pathomorphological and histochemical changes characteristic of chronic bronchitis, pulmonary emphysema, focal pneumosclerosis, and initial manifestations of pulmonary hypertension were found in the deceased obese patients. It was established that the severity of pathological changes was interrelated with the degree of expression of leptin and type IV collagen by the lungs: in the group of deceased with normal body weight and minor and moderate pathological changes, the level of leptin expression was assessed as “insignificant” (“+”), whereas, in the group of deceased with obesity, significant (“+++”) leptin expression and diffuse foci of sclerosis were identified in all structural parts of the lungs.
When evaluating the studied indicators at the end of the experiment (the 4th month), a significant (p<0.001) difference was established between the average body weight indicators of rats in the CL group in comparison with the O and OS groups. Significant (p<0.001) differences in body weight were also found in groups S and O, and S and OS. On the other hand, the average body weight of rats in groups CL and S, as well as O and OS, did not differ significantly (p = 0.16 and p = 0.11, respectively). Significant (p = 0.05) differences in BMI were found when comparing the CL group with the S, O, and OS groups, as well as when comparing the S and O and S and OS groups, respectively (p<0.001).
Chronic bronchitis and focal emphysema were found in rats of the S group. In rats of the O group, chronic bronchitis, initial manifestations of bronchiectasis formation, pulmonary emphysema, focal pneumosclerosis, and initial manifestations of pulmonary hypertension were found. In the OS group, the pathomorphological changes detected corresponded to those in the O group and did not differ qualitatively, apart from isolated foci of formed bronchiectasis.
As in the study of deceased patients with obesity, in the experiment, we found that the degree of severity of pathological changes was interconnected with the degree of expression of leptin in the lungs. Thus, in the CL group with minor pathological changes, the level of leptin expression was assessed as negative (“–“); in group S with moderate pathological changes - as insignificant (“+”), while in groups O and OS, where significant pathomorphological changes were found, - significant (“+++”) expression of leptin in the lungs was identified.
Our research results allow us to state that obesity is not only a dominant risk factor for developing endocrine and cardiovascular diseases but also a leading cause of severe lung pathology, particularly COPD with diffuse emphysema, pneumosclerosis, and secondary arterial hypertension.
