Genetic markers of predicting the development of pulmonary hypertension in cases of suppurative lung disease

Full Text

BACKGROUND

Suppurative lung disease represent the severe complications of community-acquired pneumonia, being characterized by the inflammatory infiltration and destruction of pulmonary tissue as a consequences of the infectious causative agents action. The primary manifestations of suppurative lung diseases include the pleural empyema without fistula (the outcome of the parapneumonic effusion) and the pleural empyema with fistula (the outcome of destructive pneumonia with the possible development of pulmonary abscess with or without the sequestration, or the pulmonary gangrene) [1]. The mortality among the patients, despite the improvement of treatment methods, remains high — from 5% to 30%, reaching 70% when associates with the significant destruction of the lung parenchyma [2–4]. The acute damage of the lungs, the pleural sepsis, the septic shock and the multi-organ system failure are the main reasons of unfavorable outcomes [5, 6]. This encourages to search for the biomarkers, including the molecular genetic markers, to detect the groups of patients with high risk of lethal outcome and early implement high-tech methods of treatment to improve survival [7–11].

Currently, for the rapid and the informative evaluation of the development of pulmonary hypertension, and of the possible interstitial edema of pulmonary tissue, echocardiography is used, with this, the main parameters are the systolic pressure in the pulmonary artery and the tricuspid regurgitation parameters (tricuspid regurgitant jet velocity, TRJV) [12]. Due to the fact that at the early stages of the lung disease, the echocardiography parameters more often correspond to the normal values, we have estimated the previously not examined potential genetic biomarkers of predicting the course of the suppurative lung disease.

Aquaporins (AQPs) represent a group of selective transmembrane channels, which are expressed in cells of all the main organs in the human organism and which are responsible for the regulation of water homeostasis [13]. The AQP monomer (having the molecular mass of approximately 30 kDa) consists of six α-spiral transmembrane domains, surrounding the pore, through which water or other molecules are passing [14].

On one of the cytoplasmic chains and on one of the external connective chains, there are two short α-spiral domains, the top of which contains a characteristic pattern from the Asparagine-Proline-Alanine family determining their selectivity for water molecules, while the variations of this domain result in the differential permeability profiles and subclasses [15]. Currently, a total of 13 unique human AQP (AQP 0–13) molecules were identified, playing various physiological and pathological roles. For the airways, as of today, four AQP are functionally significant (AQP1, AQP3, AQP4 and AQP5) [16]. Thus, the AQP1 is expressed in the endothelium of the microvessels in the airways and in the alveoli, as well as in the mesothelial cells of the visceral and parietal pleura. AQP3 was found in the epithelium of the small airways, AQP4 — at the membrane of ciliate columnar cells of the epithelium in the bronchi, trachea and nasopharynx. AQP5 is expressed in the type I alveolar epithelial cells, in the acini of the submucosal glands and in the large epithelium of the airways [17]. AQP4 significance has been intensively investigated in various diseases, such as the pathological conditions of the central nervous system [13, 18, 19] and the cardiovascular system [20, 21], retinopathy-associated diabetes [22], tumors [23], sepsis and septic shock [7, 24]. A number of studies have found that the genetic variants of the AQP4 gene can serve as prognostic candidate biomarkers in patients with craniocerebral injury (rs3763043, rs3875089) [25], hematoma in patients with hemorrhagic stroke and swelling (rs1058427) [26], hemorrhagic stroke (rs3875089, rs3763043, rs11661256) [27] and in sepsis patients (rs1058427) [7].

Despite the available information on the genetic factors of developing the pulmonary hypertension [28], the role of AQP4 in the pathogenesis of suppurative lung disease and as the predictor for complications during the suppurative lung disease remains not clarified. On the other hand, contribution of the immunological mechanisms to the development of pulmonary hypertension is well known [29], however, their possible relation to the AQP4 gene polymorphism in pathological conditions in humans is not yet understood. We supposed that AQP4 polymorphism could become the source of clinically significant biomarkers for suppurative lung diseases, informative for better understanding the multiple mechanisms of developing the pulmonary hypertension.

Aim — to clarify the contribution of the AQP4 gene polymorphic variants and pathogenically relevant immune cells levels to the development of pulmonary hypertension in patients with the suppurative lung disease.

Methods

Research design

Non-controlled prospective observational single-center clinical study.

Conformity Criteria

Inclusion criteria: the presence of a pulmonary suppurative disease (pulmonary abscess without sequestration, pulmonary abscess with sequestration, pulmonary gangrene, pleural empyema without fistula, pleural empyema with fistula) in a patient who had an episode of community-acquired bacterial infection within the previous 30 days; the age starting from 18 years; written informed consent for participation in the conducted study; the ability of the patient to follow the adequate long-term cooperation during the process of clinical research.

Exclusion criteria: the patient’s and/or his/her legal representatives’ refusing to participate in further follow-up; diagnosis of an oncological disease or tuberculosis in the patient.

Research facilities

The research work was arranged by the Federal State Budgetary Scientific Institution “Federal Research and Clinical Center for Critical Care Medicine and Rehabilitation Medicine” (FSCC CCMRM). The procedures for collecting the biomaterial were arranged at the Thoracic Surgery Department and Anesthesiology and Resuscitation Department of the State Budgetary Healthcare Institution “City Clinical Hospital named after I.V. Davydovsky”, Moscow Healthcare Department (I.V. Davydovsky City Clinical Hospital) during the period from November 2022 until August 2023.

Research findings

Funded by the Ministry of Science and Higher Education of Russian Federation to FSCC CCMRM (Principal Investigator — V.M. Pisarev).

Main research outcome: development of pulmonary hypertension.

Additional research outcome: changes in the quantity of immune cells depending on the gene polymorphism of AQP4 rs1058427.

Subgroup analysis

During the process of data analysis, we have divided the cohort of patients (n=188) into subgroups with the fistular complications (n=82) and without them (n=106), as well as into the subgroups of patients with (n=70) or without (n=118) the previous episode of COVID-19.

Methods for registration of outcomes

The DNA for the genotyping was isolated from the 200-µl portion of whole blood. The allele variants of AQP4 rs1058427 were determined using the tetra-primer polymerase chain reaction (PCR) with further electrophoretic separation and identification of the stained products in the gel. Using the Primer-BLAST software (https://www.ncbi.nlm.nih.gov/tools/primer-blast/) the following primers were selected and synthesized by the LLC “Evrogen” (Moscow):

• AQP4 1 for. 5`-TATTGGCAAAACTGGGGATT-3`;
• AQP4 2 for. 5`-CCCAATCTCTGCTCTCTCAA-3`;
• AQP4 2 rev. 5`-GATTATCAACAAATGTCACGAGAAG-3`;
• AQP4 1 rev. 5`-TGCAACCATGTTGTACCTTG-3`.

On admission to the in-patient department, the patients were evaluated by their demographic data, presence of diabetes and comorbidity scales (table 1, 2), such as the Charlson Comorbidity Index (CCI) [30] and the Cumulative Illness Rating Scale (CIRS) [25]. Severity of illness was evaluated by the Sequential Organ Failure Assessment (SOFA) scale and the Acute Physiology and Chronic Health Evaluation II (APACHE II) scale. Pleural infection severity was evaluated separately using the specialized Renal, Age, fluid Purulence, Infection source, Dietary (RAPID) scale with taking into consideration the kidney functional parameters (blood urea nitrogen), the age, the presence of pus in fluids, the source of infection, the albumin levels as the factor related to the nutrition (this scale is important for the stratification of risk for unfavorable outcome in pleural empyema patients [26].

 

Table 1 Characteristics of the patients with the suppurative-destructive diseases of the lungs on admission, Me (IQR)

Parameters	Value
Men, n (%)	129 (69)
Women, n (%)	59 (31)
Age, years	54 (41–66)
SOFA scale points on admission	2 (2–2)
APACHE II scale points on admission	5 (3–8)
Diabetes, n (%)	33 (17)
Charlson comorbidity index value	2 (1–4)
CIRS comorbidity scale index	10 (7–13)
Pleural infection assessment using the RAPID scale	1 (1–2)

 

Table 2 Significance of differences for the parameters in cases of pulmonary hypertension or its absence in patients with the suppurative-destructive lung diseases, Me (IQR)

Parameters	Pulmonary hypertension		p
	Presence n=69	Absence n=119
Age, years	60 (48.7–69)	51 (40–62.7)	0.002*
Gender, n • men • women	51 18	78 41	0.2571**
CCI index	3 (1.7–5)	2 (1–4)	0.007*
CIRS scale points	11 (8.7–16)	9 (7–12)	0.003*
Diabetes, n • present • absent	14 55	19 100	0.5511**
SOFA scale	2 (2–3)	2 (2–2)	0.023*
APACHE II scale	6 (5–8.2)	5 (3–7.7)	≤0.001*
RAPID scale	2 (1–3)	2 (1–3)	0.32*

Note. * — Mann–Whitney U-criterion; ** — exact Fisher test.

 

The echocardiography method was employed to determine the presence of pulmonary hypertension, which was confirmed by the systolic pressure levels in the pulmonary artery being ≥36 mm.Hg. and by the regurgitation velocity in the tricuspid valve (tricuspid regurgitant jet velocity, TRJV) value ≥2.9 m/sec [12].

The testing of blood samples was performed using the Sysmex XN-1000 automated hematological analyzer.

Statistical analysis

Principles of calculating the sample size. Taking into consideration the mortality in case of suppurative lung disease, equaling an average of 16%, the approximated size of the cohort was calculated by the following formula: n=(t²×P×Q)/∆², where t — is the value of Student test (1.96 at the significance level of 0.05); ∆ — is the error margin (5%); P — is the percentage of cases, in which the tested parameter — the survival — was reported (84); Q — is the percentage of cases in which the tested parameter was not found (16). The calculated sample size (n) was 206 patients. Taking into consideration the possible losses, the suggested sample size was increased by 5% — up to 216 patients.

Methods of statistical analysis of data. The statistical analysis was carried out using the SigmaStat software, version 3.5. The quantitative parameters were evaluated for the normality of distribution using the Shapiro–Wilk test. The quantitative parameters, which had normal distribution, were described using the mean arithmetic values (M) and the standard deviations (SD) along with the levels of 95% confidence interval (95% CI). In case of absence of normal distribution, the quantitative data were described employing the median (Me) and the interquartile range (IQR). The comparison of the two groups by the variables, the distribution of which was normal and the dispersions were equal, was carried out using the t-Student test. In case when the type of the distribution of variables differed from the normal one, the calculations were done by means of the Mann–Whitney U-test. The categorical data were described with reporting the absolute values and the percentages. The comparison of percentages when analyzing the confusion matrices was performed by using the χ²-test with the Yates’ correction for the sample continuity and the Fisher’s exact test (FET). As the quantitative measure of the effect when comparing the relative parameters, the odds ratio was used with the 95% confidence interval (OR; 95% CI). The significance of differences was considered at p < 0.05.

RESULTS

Research sample (participants)

The research included 216 patients with suppurative lung disease developed following an episode of community-acquired pneumonia within the previous 30 days. The lung disease cases without fistular complication were considered as the outcome of the parapneumonic effusion, whereas cases complicated with fistular — resulted from the pulmonary abscess with or without sequestration, or a pulmonary gangrene. The diagnosis of suppurative disease of the lungs was set based on the results of computed tomography conducted on admission to the in-patient department.

The conclusion on the patient having a previous episode of SARS-CoV-2 infection was based on the documented results of PCR-diagnostics, independently on the date of the disease. The treatment of COVID-19 was arranged taking into consideration the temporary recommendations on prevention, diagnosis and treatment of COVID-19 including updates.

The research on the development of pulmonary hypertension included 188 patients, of which 69 had pulmonary hypertension and 119 had no pulmonary hypertension.

Medical procedure description

Within 2 hours after admission to the in-patient Department, the patient was undergoing the draining of the pleural cavity (Bülau’s method). After the installation of the draining tube, the differentiation was carried out between the pleural empyema without fistula and the pleural empyema with fistula. The presence of air shunting via the draining tube was indicating the pleural empyema with fistula. At the Thoracic Department or at the Resuscitation and Intensive Care Department, the patients were receiving the infusion-correcting therapy, the antibiotic therapy according to the strategy of controlling the antimicrobial therapy; the prevention of thromboembolic complications (anticoagulant therapy + elastic compression of the veins in the lower limbs); the prevention of stress-ulcers; the adequate pain therapy; the symptomatic therapy; the respiratory support, if necessary. The laboratory tests included the clinical hematology panel, the clinical biochemistry panel; coagulation tests were also carried out along with the tests showing the acid-base status. Further tactics of managing the patient was defined after 48–72 hours with taking into consideration the efficiency of initial therapy and, in cases of the presence of indications, a discussion was held on arranging the video-thoracoscopic sanitation of the pleural cavity. The efficiency of antibiotic therapy was defined 72 hours after the treatment initiation.

The video-thoracoscopic sanitation of the pleural cavity was conducted under general anesthesia with separate bronchial intubation using the dual-lumen tube. One-lung ventilation was necessary for the complete collapsing of the lung and for creating the free space, which allowed for doing the thorough and comprehensive examination of the thoracic cavity.

Upon hospitalization, the patients with pleural empyema and with a fistula in the settings of persisting air shunting via the draining tube were undergoing the temporary occlusion of the bronchi (by means of installing bronchial blocker with its further removal) for the purpose of occluding the bronchopleural fistula. The evaluation of the degree of expansion of the pulmonary tissue (absence of pneumothorax after clamping the draining tube) was done in the absence of the production of suppurative discharge and air via the draining tube as determined by the radiography of the chest cavity organs.

Upon the normalization of the clinical parameters and laboratory findings and upon the expansion of the pulmonary tissue, the draining tube was removed and the patient was discharged from the in-patient Department.

Primary research findings

The distribution of frequencies for the AQP4 rs1058427 genotypes was the following (n=188): GG — 78%; GT — 21%; TT — 1%, which corresponded to the genetic equilibrium law stipulated by Hardy-Weinberg (χ²=0.109; p=0.741) and did not differ from the distribution in the group of relatively healthy donors (GG — 80%, GT — 18%, TT — 2%; χ²=0.85; p=0.36; n=154; Fig. 1), as well as from the genotype frequencies in the North-American population, for which, the association was shown between the AQP4 rs1058427 polymorphism and the cerebral edema after the hemorrhagic stroke [31].

 

Fig. 1. The distribution of AQP4 rs1058427 genotypes among the patients with the suppurative-destructive lung diseases, among the relatively healthy donors and in the North-American population [31].

 

In patients with the suppurative disease of the lungs with or without the presence of fistular complications, significant differences were observed when comparing the systolic pressure levels in the pulmonary artery [p=0.006, Mann–Whitney U-criterion; M (IQR) 30 (28–36) and 35 (30–42); n=188] and the peak velocity of tricuspid regurgitation [p=0.006, Mann–Whitney U-criterion; M (IQR) 2.5 (2.4–3) and 2.8 (2.5–4); n=188] (Fig. 2).

 

Fig. 2. The comparison of the parameters of systolic pressure in the pulmonary artery and the peak velocity of tricuspid regurgitation in patients with the suppurative-destructive diseases of the lungs depending on the presence/absence of fistular complications. PASP — pulmonary artery systolic pressure; TRJV — tricuspid regurgitation jet velocity.

 

In patients with the minor T allele of the AQP4 rs1058427 (genotypes GT, TT), the disease course was more often complicated by the development of pulmonary hypertension (p=0.000097, FET; OR=4.19, 95% CI 2.02–8.68; RR=2.16, 95% CI 1.53–3.05; n=188). The systolic pressure levels in the pulmonary artery and the peak velocity of tricuspid regurgitation in patients with various genotypes of AQP4 rs1058427 in the subgroups with fistular complications (p=0.0065, FET; OR=5.2, 95% CI 1.52–17.74; RR=1.98, 95% CI 1.32–2.98; n=82) and without fistular complications (p=0.0042, FET; OR=4.2, 95% CI 1.61–10.95; RR=2.46, 95% CI 1.42–4.27; n=106) also significantly differed (Fig. 3).

 

Fig. 3. The comparison of the parameters of systolic pressure in the pulmonary artery and of the peak velocity of tricuspid regurgitation in patients with the suppurative-destructive diseases of the lungs depending on the AQP4 rs1058427 genotype. PASP — pulmonary artery systolic pressure; TRJV — tricuspid regurgitation jet velocity; FET — Fisher exact test; OR — odds ratio; RR — relative risk; CI — confidence interval.

 

When dividing the patients into subgroups depending on the presence of COVID-19 episode, the association persisted only in patients with no history of COVID-19 infection (p=0.001, FET; OR=4.5, 95% CI 1.88–10.76; RR=2.24, 95% CI 1.47–3.42; n=118); in patients with a history of COVID-19, no association was found between the AQP4 rs1058427 polymorphism and the systolic pressure in the pulmonary artery along with the peak velocity of tricuspid regurgitation (p=0.0809; n=70) (Fig. 4).

 

Fig. 4. The comparison of the parameters of systolic pressure in the pulmonary artery and of the peak velocity of tricuspid regurgitation in patients with the suppurative-destructive diseases of the lungs with various AQP4 rs1058427 genotypes depending on presence of the past episode of COVID-19. PASP — pulmonary artery systolic pressure; TRJV — tricuspid regurgitation jet velocity; FET — Fisher exact test; OR — odds ratio; RR — relative risk; CI — confidence interval.

 

Additional research outcomes

On days 1, 3, 5, 7 and on the last day of hospitalization among the patients with the presence/absence of fistular complication and with various genotypes of AQP4 rs1058427, the neutrophils, lymphocytes and monocytes in blood were were counted.

Neutrophils

In the presence of fistular complication, the difference in the levels of neutrophils was found only on the fifth day of hospitalization: in patients with minor AQP4 rs1058427 genotypes (GT, TT), the blood neutrophil count was significantly lower [p=0.031, Mann–Whitney U-criterion; M (IQR) 5.9 (4–8.9) and 8.4 (5.525–11.65); n=85]. For the subgroups of patients without fistular complication, the neutrophil count on all the hospitalization days did not differ between the compared genotypes.

In patients with the fistular complication and with a history of COVID-19 episodes, on all the hospitalization days, no differences were found in the levels of neutrophils. When comparing the neutrophil content in patients with fistular complication and with no history of COVID-19 infection, the difference was found on the 5th day of hospitalization [p=0.034, Mann–Whitney U-criterion; M (IQR) 5.4 (4–8.9) and 9.25 (5.9–13.85); n=54]: in patients with minor genotypes GT, TT of AQP4, the blood neutrophil content was significantly lower. When comparing the neutrophil levels in patients with COVID-19 and with no history of COVID-19 infection in the absence of fistular complication, no differences were detected on all the hospitalization days (Supplement 1).

Lymphocytes

For the subgroups of patients with fistular complications and without fistular complications and with various genotypes of AQP4 rs1058427, including the patients having a past episode of COVID-19 and with no history of COVID-19 infection, no difference was found in the levels of circulating lymphocytes on any of the hospitalization days (Supplement 2).

Monocytes

Except for the last day of hospitalization, the number of monocytes in the subgroup of patients with fistular complication did not differ for various AQP4 rs1058427 genotypes. On the last day of hospitalization in patients with minor genotypes of AQP4 GT, TT, the blood monocyte content was significantly higher [p=0.017, Mann–Whitney U-criterion; M (IQR) 0.7 (0.6–0.8) and 0.5 (0.325–0.7); n=85]. For the subgroups of patients without fistular complication and with various genotypes of AQP4 rs1058427, the levels of blood monocytes did not differ on any of the hospitalization days.

When comparing the monocyte content in patients with fistular complications and with a past episode of COVID-19, the difference was found on the last day of hospitalization [p=0.048, Mann–Whitney U-criterion; M (IQR) 0.6 (0.4–0.7) and 0.8 (0.75–0.9); n=31]: in patients with minor genotypes of AQP4 GT, TT, the blood monocyte count was higher. When comparing the monocyte levels in post-COVID-19 patients without fistular complication to the patients with no fistula and no history of COVID-19 infection, there were no differences detected on any of the day (Supplement 3).

Undesirable phenomena

No cases of undesirable phenomena were reported during the course of our research.

DISCUSSION

Summary of the research findings

In patients with suppurative lung disease, the genetic polymorphism of the 3`-area of the AQP4 gene affects the risk of developing pulmonary hypertension and associates with altered numbers of immune cells during hospitalization.

Interpretation of the research findings

Recent research works have demonstrated that aquaporins play the key role in the respiratory diseases, including the chronic obstructive pulmonary disease, the asthma, the acute respiratory distress-syndrome and the non-small-cell lung cancer. Their role includes the assistance in the transmembrane transport of water and other minor molecules, the regulation of cellular movement and migration and the modulation of inflammatory reactions [32].

It is known that the abnormalities of bronchial passability, of the draining function of the bronchi and of the microcirculation at the zone of inflammation within the pulmonary tissue is one of the main factors of the suppurative lung disease. It was shown that the increased expression of AQP1 and AQP5 genes in the small airways defines their potential contribution to the development of submucosal edema and excessive production of tenacious mucus [32]. It appears that the similar effects are also reported for the AQP4, with which the infiltration and the progression of edema in the bronchial tree and in the lung parenchyma impaires microcirculation in the pulmonary parenchymaresulting in the congestion and the thrombosis of pulmonary vessels, the development of inflammation and the necrosis of pulmonary tissue [1].

It is also known that AQP4 polymorphism associates with the development of edema [31]. We have chosen the genetic variant within the substitution in the regulatory 3`-zone of the AQP4 gene. The substitution point in this variant is included into the sequences encoding four separate transcripts of long non-coding RNA (lnсRNA): ENST00000579964.6 AQP4-AS1-203, 1645 base pairs (b.p.) (ENST00000628174.2 AQP4-AS1-206, 919 b.p.; ENST00000582605.5 AQP4-AS1-204, 525 b.p; ENST00000627963.2 AQP4-AS1-205 381 b.p). At least one of transcripts, AQP4-AS1, decreases the level of AQP4 expression [33]. It is possible that the substitution of guanine by thymin in the AQP4 rs1058427 gene variant results in decreasing the number of AQP4-AS1, promoting to the increased expression of AQP4 and to the increasing the synthesis of aquaporin molecules. It suggests that, in the carriers of allele T of AQP4 rs1058427, because of the higher expression of AQP4 in the perivascular area the intima in the vessels (including the pulmonary ones) becomes thicker due to enchanced accumulation of water molecules. Other possible explanation of developing the pulmonary edema among the carriers of genotypes AQP4 GT and TT of rs1058427 is the loss of integrity of the alveolar epithelium due to the proinflammatory actions of neutrophils adhered to the surface of the endothelium. Indeed, the role of AQP4 in the increased migration of immune cells was shown in the recent research works [34]. The increased levels of pro-inflammatory immune cells (primarily neutrophils) increases the probability of damaging the vessels, adding to the increase of the vascular permeability and to the transition of interstitial fluid into the alveolar space. Thus, it can be suggested that the presence of alternative minor allele T in patients with suppurative lung disease modifies the AQP4 expression in the alveolar epithelium cells, increasing the transport of water molecules and aggravating the development of the edema.

Interestingly, the presence of the minor allele Т of the AQP4 gene was also associated with the accumulation of monocytes in the circulation, with the monocytes actively participating in the pathogenesis of pulmonary hypertension [29]. It cannot be ruled out that exactly the two factors — the alteration of the AQP4 expression as a result of mutation and the intensive migration of neutrophils and monocytes — contribute to the increased risk of developing the pulmonary hypertension in suppurative lung diseases patients. There is also insufficient data to rule out the direct relation between the minor mutation and the ability of the immune cells to migrate or, upon migrating, to accumulate in the pulmonary tissue, contributing to the development of the pro-inflammatory phenotype — the promoter of the development of pulmonary hypertension in the settings of hypoxia, characteristic for a suppurative lung disease [28]. The cancellation of the statistical significance for the relation between the allele Т of AQP4 and the signs of pulmonary hypertension in patients with a suppurative lung disease having a previous episode of COVID-19, indicates the presence of the virus-induced long-term disorders in the functioning of multiple key participants of the pathological process (arterial smooth-muscle cells; endothelial cells of lung vessels; fibroblasts, providing the remodeling of the vessel wall; immune system cells). Apparently, the intensity, the wide spectrum of cells involved into the pathogenesis and the duration of such abnormalities as a result of virus-induced effects, determine the loss of significance for the contribution of the genetic polymorphism of AQP4 to the increasing the risk of developing the pulmonary hypertension.

Thus, the detectable clinical effects associated with the carriership of the allele T of AQP4 gene (genotypes AQP4 GT and TT, rs1058427), are determined by the development of the pro-inflammatory and, presumably, the atherosclerotic lesions in the lung vessels with further impairment of the microcirculation in the pulmonary tissue, resulted in formation of necrotic areas,development of pulmonary hypertension and pulmonary edema.

Further expansion of the research sample is required to validate the detected patterns and tendencies, detailing their informativeness as the genetic and the immunological predictive markers for pulmonary hypertension development as a complication in patients with suppurative lung disease.

Research limitations

The limitation of our research work is its single-center design (arrangement within the premises of a single medical facility), due to which, the validation of the results is needed within the premises of other hospitals.

CONCLUSION

The suppurative lung disease patients that are the carriers of the minor allele Т of AQP4 rs1058427 (genotypes GT and TT) exhibit a high risk of developing the pulmonary hypertension. Previous medical history of COVID-19 cancels the statistical significance of the association of the Т allele and the development of this complicatio.

ADDITIONAL INFORMATION

Supplement 1. Monocytes count levels in patients with the suppurative-destructive diseases of the lungs with and without fistula, Mе (IQR)

doi: 10.17816/clinpract690269-4392441

Supplement 2. Lymphocyte count levels in patients with the suppurative-destructive diseases of the lungs with and without fistula, Mе (IQR).

doi: 10.17816/clinpract690269-4392442

Supplement 3. Monocytes count levels in patients with the suppurative-destructive diseases of the lungs with and without fistula, Mе (IQR)

doi: 10.17816/clinpract690269-4392443

Author contributions: A.G. Chumachenko, definition of the concept, statistical processing, writing the article; D.L. Fetlam, collection and analysis of clinical material, working with data, statistical processing, writing the article; V.M. Pisarev, ideas and organization of research, definition of the concept, working with data, statistical processing, validation, editing of the final version of the manuscript. Thereby, all authors provided approval of the version to be published and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Ethics approval: Approval to conduct scientific research was received at the meeting of the Ethics Committee of the FNCC PP (Protocol No. 2/22/1, dated 2022 July 26). All study participants signed an informed consent form before being included in the study.

Funding source: Biomarker research studies were funded by the Ministry of Science and Higher Education of Russian Federation to FSCC CCMRM (Principal Investigator — V.M. Pisarev). This publication was not supported by any external sources of funding.

Disclosure of interests: The authors declare that they have no competing interests.

Statement of originality: The authors did not use previously published information (text, illustrations, data) while conducting this work.

Data availability statement: The editorial policy regarding data sharing does not apply to this work, data can be published as open access.

Generative AI: Generative AI technologies were not used for this article creation.

About the authors

Anastasya G. Chumachenko

Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology

Email: a_chumachenko@mail.ru
ORCID iD: 0000-0001-6279-2849
SPIN-code: 4093-1091

PhD

Russian Federation, Moscow

Dmitriy L. Fetlam

Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology

Email: dmfetlam@yandex.ru
ORCID iD: 0000-0002-5477-4920
SPIN-code: 5273-4406
Russian Federation, Moscow

Vladimir M. Pisarev

Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology

Author for correspondence.
Email: vpisarev@gmail.com
ORCID iD: 0000-0002-5729-9846
SPIN-code: 1605-3144

MD, PhD, Professor

Russian Federation, Moscow

References

Supplementary files