INTERLEUKIN-8 AS A MARKER OF PRETERM LABOUR Текст научной статьи по специальности «Клиническая медицина»

MEDICAL SCIENCES

ИНТЕРЛЕЙКИН- 8 КАК МАРКЕР ПРЕЖДЕВРЕМЕННЫХ РОДОВ

Дяк К.В.

Юзько А.М.

Семеняк А.В.

Высшее государственное учебное заведение Украины «Буковинский государственный медицинский университет»

(Украина, г. Черновцы)

INTERLEUKIN-8 AS A MARKER OF PRETERM LABOUR

Dyak K.V.

post-graduate student of the Department of Obstetrics and Gynecology of the Higher state educational institution of Ukraine "Bukovinian State Medical University", Chernivtsi

Yuzko O.M.

the doctor of medicine, Professor, Head of the Department of Obstetrics and Gynecology of the Higher state educational institution of Ukraine "Bukovinian State Medical University", Chernivtsi

Semeniak A. V.

сandidate of Medical sciences, docent of the Department of Obstetrics and Gynecology of the Higher state educational institution of Ukraine "Bukovinian State Medical University", Chernivtsi

Аннотация

Введение. Преждевременные роды занимают одно из ведущих мест в структуре осложнений беременности, что делает вопрос ранней диагностики актуальным. Сложность решения проблемы заключается в наличии различных причины, приводящих к преждевременным родам, несовершенство современных методов диагностики, лечения и своевременной профилактики угрозы прерывания беременности. Одним из возможных маркеров диагностики преждевременных родов является определение интерлейкина 8 (ИЛ-8) в крови или шеечных выделениях, однако, на сегодняшний день это остается дискуссионным.

Цель. Определить роль ИЛ-8 в развитии преждевременных родов.

Материалы и методы. Проведено клинико-лабораторное обследование 60 беременных с дополнительным определением ИЛ-8: 40 - основная группа, находившихся на стационарном лечении с диагнозом ложные схватки; 20 - контрольная группа, в состав которой входили беременные без диагноза ложные схватки. Определение ИЛ-8 проводили в слизи из цервикального канала и сыворотке крови на иммуно-ферментном анализаторе Rider Myltiskan EX с помощью наборов реактивов и тест-систем.

Результаты исследования. При определении уровня ИЛ-8 в сроке 22-30 недель и 6 дней установлено достоверное увеличение в цервикальной слизи и достоверное уменьшение в сыворотке крови при сравнении с контрольной группой. В группе беременных 22-27 недель и 6 дней структурные изменения шейки матки были только в двух случаях (8,7%), в группе 28-30 недель и 6 дней структурных изменений шейки матки не было. В сроке 31-33 недели и 6 дней установлены аналогичные достоверные различия содержания ИЛ-8, однако, структурные изменения шейки матки выявлено у 66,7%, из них преждевременные роды в 33,3%. Установлено, что уровень ИЛ-8 у беременных с повышенным количеством лейкоцитов во влагалище был ниже в сравнении с беременными с нормальным количеством лейкоцитов.

Выводы. При наличии ложных схваток и преждевременных родов, независимо от срока беременности, происходит достоверное повышение ИЛ-8 в несколько раз, не вызванное инфекционным фактором. В сроке беременности 31-34 недели достоверное повышение ИЛ-8 до 30,61 нг / мл указывает на возможность преждевременных родов в 33,3%. Повышение ИЛ-8 в цервикальной слизи до 33,92 нг / мл при наличии болезненных сокращений матки в сроке беременности 22-31 недели предшествует появлению структурных изменений шейки матки.

Abstract

Introduction. Preterm labor is on one of the leading places in the structure of pregnancy complications, which makes the problem of early diagnosis relevant. This problem is hard to solve due to different causes leading to preterm delivery, imperfection of modern methods of prognostication, treatment and timely prevention of the threat of abortion. One of the possible markers of diagnosis of preterm labor is the determination of interleukin 8 (IL-8) in the blood or cervical discharges, however, it remains controversial to date.

Objective. To determine the role of IL-8 in the development of preterm labour.

Material and methods. Clinical and laboratory examination of 60 pregnant women with additional determination of IL-8 was performed: 40 of them in the main group were on inpatient treatment with a diagnosis of false pains; 20 - the control group consisting of pregnant women without a diagnosis of false pains. The determination of IL-8 was performed in the mucus from the cervical canal and in the blood serum on the Rider Myltiskan EX immuno-enzyme analyzer using a set of reagents and test systems.

Results. After determining the level of IL-8 in the period of 22-30 weeks and 6 days, a significant increase was found in the cervical mucus and a significant decrease in the serum compared to those in the control group. In the group of pregnant women 22-27 weeks and 6 days, structural changes in the cervix only were observed in two cases (8.7%), in the group of 28-30 weeks and 6 days there were no structural changes in the cervix. With the term 31-33 weeks and 6 days, the similar significant differences in the content of IL-8 were found, however, the structural changes in the cervix were detected in 66.7%, of which 33.3% were premature deliveries. It was found that IL-8 level in pregnant women with elevated white blood cell count was lower in comparison with pregnant women with normal white blood cell count.

Conclusions. In case of false pains and preterm delivery, regardless of the term of pregnancy, IL-8 increases by several times which is not caused by an infection factor. In the period of pregnancy 31-34 weeks, a significant increase in IL-8 to 30.61 ng / ml suggests the possibility of preterm labor in 33.3%. Elevation of IL-8 in the cervical mucus up to 33.92 ng / ml alongside with painful uterine contractions during the period of pregnancy 22-31 weeks precedes the appearance of structural changes in the cervix.

Ключевые слова: преждевременные роды, интерлейкин 8 Keywords: preterm labour, interleukin-8.

Introduction. Preterm labor (PL) has steadily occupied one of the leading places in the structure of complicated pregnancy in the last two decades. According to WHO recommendations, the labor is considered to be preterm after 22 weeks of gestation when the weight of the fetus is more than 500 grams, making the problem even more relevant and leading to an increase in the frequency of PL in the range of 6-10% [5]: France, Great Britain, Norway 7, 2-7.9%, in Germany, Hungary, USA 9-10%. In Ukraine, the prevalence rate of preterm labor varies from 3.5 to 4.7% in different regions and has a steady tendency to an increase, which is associated, like in the developed countries, with the widespread introduction of auxiliary reproductive technologies, an increase in the incidence of multiple pregnancy that increases the risk of abortion. [2, 3, 8]. Considering the progressive increase in the proportion of women who wish to give birth at the late reproductive age, the reduction in PL frequency should not be expected, therefore early diagnosis and prevention are important as they promote timely treatment of pregnant women and a decrease in the incidence of premature infant diseases [3].

The share of premature infants accounts for 6070% of early neonatal mortality. Stillbirths in preterm labor are observed by 8-13 times more frequently than in case of urgent delivery [6]. Reducing perinatal and early neonatal mortality in developed countries is due to the improvement of neonatal care. At the same time, the frequency of the premature births themselves can not be reduced, despite the use of drugs for pregnancy prolongation [7]. The problem of the prevention of PL is hard to solve due to the multicausality of this pathology, the imperfection of modern methods for its prognostication, which dictates the need to find new methods to prognose PL, as well as the application of new and more effective ways to prolongate pregnancy.

One of the markers to diagnose PL is to determine the content of interleukins in the blood or cervical secretions, in particular, the importance of interleukin 8 (IL-8) or chemokine CXCL8, (Interleukin-8, IL-8), which is one of the major pro-inflammatory chemo-kines that is formed by macrophages, epithelial and en-dothelial cells. The main feature of the chemokines is to supply chemotaxis to the inflammation zone of different types of cells: neutrophils, monocytes, eosino-

phils, T cells. IL-8 (IL-8), known as the activation factor of neutrophils, as it activates mainly neutrophils, to a lesser extent, other granulocytic leukocytes and monocytes. The elevated level of IL-8 is associated with chronic and acute inflammatory conditions. IL-8 production begins after influence of the endogenous IL-1, IL-3, FNP, GM-CSF etc. regulators on the cell, and the interleukins act through high-affinity, highly specific receptors on the membrane target cells. Unlike the classical hormones, most cytokines are molecules of para-crine, local action. They are produced and used by the cells that are in close interaction. However, they can affect the cells that secrete this cytokine (autocrine action) [8, 9]. IL-8 has pronounced proinflammatory properties, causing the expression of intercellular adhesion molecules and enhancing the adhesion of neutro-phils to endothelial cells and subendothelial matrix proteins, indicating its major role in the formation of the inflammatory response [1, 8, 9].

Increasing the concentration of IL; 8 - a cytokine with a powerful proinflammatory effect - is one of the leading pathogenetic factors of structural changes in the cervix and isthmic-cervical insufficiency. Under the influence of proinflammatory biologically active substances, the contractive activity of myometrium and numerous enzymes such as collagenase, metal proteases, which disturb the normal structure of the connective tissue of the cervix, are initiated. It results in shortening and smoothing the cervix as well as in gradual opening the uterine orifice. As the results of various studies have shown, more than half of pregnant women with is-chemic heart failure have elevated concentrations of pro-inflammatory IL-8, however, the question remains controversial and needs further research [4, 10].

Objective. To determine the role of IL-8 in the development of preterm labour.

Material and methods. Clinical and laboratory examination of 60 pregnant women with additional determination of IL-8 was performed: 40 of them are the main group, whose patients are on an inpatient treatment with a diagnosis of false pains; 20 patients are in the controle group with pregnant women who were not diagnosed with false pins. The gynecological and somatic history of all pregnant women was studied as well as the course of pregnancy, the presence of complications and the state of the cervix. In the course of the analysis, four subgroups have been formed, according

to the classification of preterm births. The first subgroup of the main group includes 23 pregnant women with a term of 22-27 weeks and 6 days, the second subgroup - 6 (28-30 weeks and 6 days), the third one - 9 (31-33 weeks and 6 days), the fourth one - 2 (34 -36 weeks and 6 days).

The determination of IL-8 was performed in the mucus from the cervical canal and blood serum on the Rider Myltiskan EX immuno-enzyme analyzer using a set of reagents and test systems for quantitative determination of IL-8 in accordance with the manufacturer's instructions (Vector-best).

Results and discussion.

The average age of the patients included in the study was 27.6 years. The average gestational age at the time of the analysis was 26.1 weeks of gestation. The examination for biochemical markers of preterm birth was carried out during hospitalization before the vaginal examination and administering the therapy.

False pains were diagnosed on the basis of complaints, increased uterine tone and structural changes in the cervix. Regardless of their cervix condition, all pregnant women were prescribed a therapy aimed at preserving the pregnancy: under 25 weeks - magnesium sulfate 20 ml 25% by intravenous infusion with 200 ml isotonic sodium chloride solution, after 25 weeks hex-oprenal sulfate 25 ^g (5 ml) in for intravenous infusions with 400 ml of isotonic sodium chloride solution, under 34 weeks the prevention of respiratory syndrome was performed - intramuscular administration of 24 mg betametazone (12 mg for two days) or 24 mg of dexame-thasone (6 mg every 12 hours for two days).

No significant differences were detected during the clinical and statistical analysis of the state of somatic and reproductive health between pregnant women of both groups.

Determining the quantitative composition of IL-8 in pregnant women in the main group found that in all subgroups there was a significant increase in cervical mucus and, at the same time, a significant decrease in the serum, regardless of the duration of pregnancy, that is, in all cases, the increased uterine tone, relevant complaints and structural changes in the cervix.

Determining the level of IL-8 in 23 pregnant women with the term of 22-27 weeks and 6 days found that the average index in the cervical mucus was 31,42 ± 5,14 ng / ml, in the blood serum - 19,6 ± 3,87 ng / ml, which significantly differed from that in the control group: in the cervical mucus it was 5.8 ± 1.32 ng / ml, in the serum 86.25 ± 6.64 ng / ml (p <0.05). In this group of pregnant women, structural changes in the cervix were only observed in two cases (8.7%), one of which was the prolapse of the amniotic sac with the further development of premature labour. A local increase in IL-8 in the term of pregnancy 22-27 weeks can lead to painful uterine contractions, which, with immediate preserving therapy, prevents the development of structural changes in the cervix. Considering that IL-8 is a proinflammatory cytokine, the presence of local inflammatory process was determined by bacterioscopic and bacteriological studies of vaginal discharge and the cervical canal. At the same time, it was found that an increase in the number of leukocytes more than by 15-

The scientific heritage No 17 (17),2017 20 in sight, indicating the inflammatory process and which could be a cause for the increase in IL-8, was observed in 11 cases (47.8%). To exclude the infectious factor as a cause of an increase in IL-8, we determined the level of IL-8 in pregnant women with an existing inflammatory process in the vagina and the cervical canal with increased leukocytes and with normal number of leukocytes. It was established that when the vaginal leukocytes increased, the mean IL-8 value was 23.09 ng / ml, which was lower than that for rare leukocytes -39, 75 ng / ml.

Six pregnancies with the term of 28-30 weeks and 6 days showed that the average index in cervical mucus was 33.92 ± 4.02 ng / ml, in the serum 20 ± 26.5 ng / ml, which also differed significantly compared to those in the control group: 6.44 ± 0.65 ng / ml for the cervical mucus, 63.21 ± 0.94 ng / ml for the blood serum (p <0.05). In all cases there were no structural changes in the cervix. A pathologically elevated amount of leukocytes in vaginal discharge onle was in one case (16.7%), where IL-8 was 12.0 ng / ml, which was almost three times lower than in the main group, but twice higher compared to the control group.

Thus, IL-8 increases reliably in the presence of painful contractions of the uterus at a term of pregnancy of 22-30.6 weeks and its increase precedes the appearance of structural changes in the cervix. The infectious factor in this case has no crucial role and influence on the level of IL-8.

9 pregnant women with the term of 31-33 weeks and 6 days, were found to have the average index in the cervical mucus 30.61 ± 10.27 ng / ml, that in the blood serum 26.5 ng / ml, which also differed significantly when compared with the control group: 3.5 ng / ml in the cervical mucus (p <0.05). Structural changes in the cervix were found in six pregnancies (66.7%), of which premature labor in two cases (33.3%). An infectious process in the vagina was found in 55.6% of patients, with 80% of the structural changes in the cervix. However, the level of IL-8 in pregnant women with elevated levels of leukocytes in the vagina was lower compared with pregnant women having normal leukocyte count and it was 26.6 ng / ml. In the absence of an inflammatory reaction, the IL-8 level is 35,625 ng / ml. Therefore, it can be concluded that IL-8 rises both in the presence of signs of false pains, and in the case of preterm labor, the increase in IL-8 is not caused by the inflammatory process, it is important to predict the development of preterm labor, especially in the term of 31-33 weeks and 6 days.

After 34 weeks of pregnancy, only two pregnant women in the main group were under the risk of premature labour with similar changes observed: a reliable increase in IL-8 in the cervical mucus on average 80 ng / ml, and 3.5 ng / ml in the control group. Structural changes in the cervix are found in 50%. Bacterioscopy and bacteriological studies of the vaginal discharges and those from the cervical canal did not find any pathological changes.

Conclusions.

1. There is a reliable increase in IL-8 by several times in the presence of false pains and premature labour, regardless of the term of pregnancy, that is, in all

cases of an increased uterine tone, coresponding complaints and structural changes in the cervix.

2. With the term of pregnancy 31-33 weeks and 6 days, a significant increase in IL-8 to 30.61 ng / ml indicates a likelyhood of preterm labor in 33.3%.

3. Increasing IL-8 in the cervical mucus up to 33.92 ng / ml in the presence of painful uterine contractions in the term of pregnancy 22-30.6 weeks precedes the appearance of structural changes in the cervix.

4. The infectious factor does not have crucial role or influence on the level of IL-8.

Prospects for further research. To study the dependence of IL-8 on the vaginal microbiocenosis.

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