Association of raised titres of antibodies to Chlamydia pneumoniae with a history of pre-eclampsia

Association of Chlamydophila pneumoniae infection and hypertension during pregnancy - A case control study

BACKGROUND

The association of Chlamydophila pneumoniae infection with essential hypertension is known but its association with hypertension during pregnancy is controversial. Hence, this study aimed to explore the association of C. pneumoniae infection with hypertension during pregnancy. The objectives were to compare the presence of C. pneumoniae DNA in trophoblastic cells of placenta between hypertensive and normotensive pregnant women and to find out the presence of inflammatory marker (HSP-60) and the seropositivity (IgG and IgA) of C. pneumoniae in them.

MATERIALS AND METHODS

The study was conducted at a tertiary-care institute, in South-India between 2018 and 2020. Women with hypertension during pregnancy were study group (75) and normotensive pregnant women were control group (75). IgG and IgA antibodies, HSP-60 against C. pneumoniae were estimated by ELISA from 5 ml of venous blood. C. pneumoniae DNA was extracted from placental tissue after delivery and tested by RT-PCR.

STATISTICAL ANALYSIS

The association between C. pneumoniae DNA, seropositivity and hypertension was determined by student test and univariate regression analysis.

RESULTS

C. pneumoniae DNA was detected in the placenta of 29.3% with hypertension and none in controls and the odds was 6.5 (OR-6.5, CI 95%). HSP-60 was elevated in women with preeclampsia and not in gestational hypertension and controls. IgA was not detected and IgG was positive in 15.2% of women with preeclampsia.

CONCLUSION

There is a significant association between C. pneumoniae infection and hypertension during pregnancy and further studies are required to fulfil the Koch's postulates to prove or disprove it as a causative agent.

Low-Dose Aspirin May Prevent Trophoblast Dysfunction in Women With Chlamydia Pneumoniae Infection

OBJECTIVE

Previously, we demonstrated that live Chlamydia pneumoniae (Cp) impaired extravillous trophoblast (EVT) viability and invasion and that Cp DNA was detected in placentas from cases with preeclampsia. We sought to elucidate whether (1) inactive forms of Cp also affect EVT function; (2) potential therapeutic interventions protect against the effects of Cp; and (3) anti-Cp antibodies are associated with preeclampsia.

METHODS

Human first-trimester EVTs were infected with ultraviolet light-inactivated Cp. Subgroups of EVTs were pretreated with low-dose acetyl-salicylic acid (ASA), dexamethasone, heparin, and indomethacin. We conducted functional assays after infection with inactivated Cp and measured interleukin 8 (IL8), C-reactive protein (CRP), heat shock protein 60 (HSP60), and tumor necrosis factor-α (TNFα) in culture media. We measured anti-Cp IgG serum levels from women who developed preeclampsia (N = 105) and controls (N = 121).

RESULTS

Inactivated Cp reduced EVT invasion when compared to noninfected cells (P < .00001) without adversely affecting cell viability. Increased levels of IL8, CRP, HSP60, and TNFα were detected in EVTs infected with inactivated Cp compared to noninfected cells (P < .0001). Only pretreatment with low-dose ASA prevented reduced EVT invasion and decreased release of inflammatory mediators (P < .01). Elevated anti-Cp IgG antibodies were more prevalent in serum from cases with preeclampsia compared to controls (67/105 vs 53/121; adjusted P = .013); elevated IgG correlated significantly with elevated serum CRP and elevated soluble fms-like tyrosine kinase-1-placental growth factor ratio.

CONCLUSION

Inactivated Cp induces decreased EVT invasion and a proinflammatory response; these effects were abrogated by pretreatment with low-dose ASA. Our results suggest an association between Cp infection, trophoblast dysfunction, and preeclampsia.

Human infectious diseases and risk of preeclampsia: an updated review of the literature

BACKGROUND

Preeclampsia (PE) is one of the major causes of maternal and perinatal morbidity and mortality, especially in low- and middle-income countries. In recent years, a growing body of literatures suggests that infections by bacteria, viruses, and parasites and their related inflammations play an important role in the pathogenesis of PE.

METHODS

We searched PubMed, Google scholar, and Cochrane databases using the following search words: "infection and preeclampsia," "bacterial infection and preeclampsia," "viral infection and preeclampsia" and "parasitic infection and preeclampsia."

RESULTS

The literature review revealed that many bacteria including Helicobacter pylori, Chlamydia pneumonia, and those are involved in periodontal disease or urinary tract infections (UTIs) and some viral agents such as Cytomegalovirus, herpes simplex virus type-2, human immunodeficiency virus, and some parasites especially Plasmodium spp. and Toxoplasma gondii can be effective in development of PE. Inflammation responses against infections has major role in the inducement of PE. The shift of immunological cytokine profile of Th2 toward Th1 and high levels of pro-inflammatory cytokines (TNF-ɑ, IL-12, IFN-γ, etc.), increase of oxidative stress, increase of anti-angiogenic proteins, increase of vascular endothelial growth factor receptor 1 (sVEGFR1), and complement C5a are the main potential mechanisms related to infections and enhanced development of PE.

CONCLUSION

Thus, early diagnosis and treatment of bacterial, viral, and parasitic infections could be an effective strategy to reduce the incidence of PE.

Maternal rubella immunity status and pre-eclampsia

PROBLEM

To determine if maternal immune maladaptation associated with pre-eclampsia is reflected in the rubella immunity status.

METHOD OF STUDY

Incidence of pre-eclampsia was compared between rubella non-immune and immune gravidae carrying a singleton pregnancy beyond 24 weeks, taking into account maternal characteristics and reported risk factors for pre-eclampsia.

RESULTS

The 9870 (10.4%) rubella non-immune gravidae among the 95 024 in the cohort exhibited no difference in incidence of underlying medical disorders, but they were slightly but significantly older, shorter, heavier, and had more pre-eclampsia (OR 1.24, 95% CI 1.05-1.47) despite having fewer nulliparas. Regression analysis confirmed an overall association between rubella non-immunity with pre-eclampsia (aOR 1.27, 95% CI 1.06-1.54), which was related to multiparas (aOR 1.42, 95% CI 1.05-1.91) and carrying a male fetus (aOR 1.37, 95% CI 1.06-1.78).

CONCLUSION

The association between rubella non-immunity and pre-eclampsia reflects immune maladaptation in multiparas and toward a male fetus.

Intracellular bacteria and adverse pregnancy outcomes

This review considers the role of intracellular bacteria in adverse pregnancy outcomes, such as miscarriage, stillbirths, and preterm labour. The cause of miscarriage, stillbirth and preterm labour often remains unexplained. Intracellular bacteria that grow either poorly or not at all on media used routinely to detect human pathogens could be the aetiological agents of these obstetric conditions. For example, Listeria monocytogenes and Coxiella burnetti are intracellular bacteria that have a predilection for the fetomaternal unit and may induce fatal disease in the mother and/or fetus. Both are important foodborne or zoonotic pathogens in pregnancy. Preventive measures, diagnostic tools and treatment will be reviewed. Moreover, we will also address the importance in adverse pregnancy outcomes of other intracellular bacteria, including Brucella abortus and various members of the order Chlamydiales. Indeed, there is growing evidence that Chlamydia trachomatis, Chlamydia abortus and Chlamydia pneumoniae infections may also result in adverse pregnancy outcomes in humans and/or animals. Moreover, newly discovered Chlamydia-like organisms have recently emerged as new pathogens of both animals and humans. For example, Waddlia chondrophila, a Chlamydia-related bacterium isolated from aborted bovine fetuses, has also been implicated in human miscarriages. Future research should help us to better understand the pathophysiology of adverse pregnancy outcomes caused by intracellular bacteria and to determine the precise mode of transmission of newly identified bacteria, such as Waddlia and Parachlamydia. These emerging pathogens may represent the tip of the iceberg of a large number of as yet unknown intracellular pathogenic agents.

Impact of seroconversion and antichlamydial treatment on the rate of pre-eclampsia among Egyptian primigravidae

OBJECTIVE

To evaluate the effect of antichlamydial treatment and Chlamydia pneumoniae seroconversion on the incidence of pre-eclampsia among Egyptian primigravidae.

METHODS

The present prospective study included 600 healthy normotensive primigravidae who attended an outpatient clinic at 10-16weeks of pregnancy. A single venous blood sample was collected to test for C. pneumonia-specific immunoglobulin G (IgG) antibodies using an enzyme-linked immunosorbent assay. Seropositive women were randomly allocated to receive or not receive antichlamydial treatment before 20weeks of pregnancy. Seronegative participants had another test at delivery for the presence of C. pneumonia-specific IgG to determine seroconversion. All participants were followed up for up to 8weeks postpartum and observed for the development of pre-eclampsia.

RESULTS

The rate of pre-eclampsia among seropositive participants differed significantly depending on whether the women received treatment or not (6.5% and 19.1%, respectively; P=0.014). No statistically significant difference in the rate of pre-eclampsia was detected between seronegative participants who underwent seroconversion and those who did not.

CONCLUSION

The present results indirectly support the hypothesis that infectious agents (in particular C. pneumoniae) have a role in the development of pre-eclampsia. The findings also indicate that antichlamydial treatment might help to reduce the incidence of pre-eclampsia.

Severe pre-eclampsia and eclampsia in Abha, the south west region of Saudi Arabia

A retrospective study was conducted over a 10-year period on 32,000 maternities at Abha General Hospital, Abha, Saudi Arabia, to estimate the contribution of eclampsia and severe pre-eclampsia to maternal mortality and morbidity and also fetal wastage. It included 18 cases of eclampsia and 297 cases of severe pre-eclampsia. Multiple regression analysis revealed that only the presence of prodromal symptoms significantly affected the occurrence of eclampsia, p < 0.05, while nulliparous patients were a high risk group for eclampsia. Maternal complications including eight cases of massive ascites occurred exclusively in severe pre-eclamptics. Although no maternal deaths were reported, the perinatal mortality rate was 16.6% and 14.1% among the eclamptics and severe pre-eclamptic patients, mainly from prematurity. Regarding the eclamptic patients, 17(94.4%) had the first fit before arrival at the hospital, 13(72.2%) before labour, while 3(16.6%) had fits before and during labour and 1(5.6%) had the fits after delivery. Suggestions are proffered to reducing maternal morbidity and perinatal mortality and morbidity.

Trophoblast infection with Chlamydia pneumoniae and adverse pregnancy outcomes associated with placental dysfunction

OBJECTIVE

We sought to determine whether Chlamydia pneumoniae impairs invasive trophoblast function and is associated with preeclampsia.

STUDY DESIGN

We conducted cell viability and invasion assays using primary extravillous trophoblast cells isolated from first-trimester placentas. We performed a case-control study to identify C pneumoniae in trophoblast cells dissected by laser capture microscopy from placentas in women with severe preeclampsia and control subjects who delivered at term.

RESULTS

Trophoblast cell viability and invasion through extracellular matrices were decreased after infection with C pneumoniae (both P < .05). C pneumoniae DNA was detected in trophoblast cells in 15/48 cases but only 3/30 controls (odds ratio, 4.1; P = .02). Positive and negative controls yielded expected results.

CONCLUSION

C pneumoniae infection can reduce trophoblast invasion into the uterine wall and is associated with preeclampsia. Further investigation of the mechanisms by which C pneumoniae induces trophoblast dysfunction, and the identification of therapies to prevent adverse outcomes attributed to trophoblast dysfunction, are warranted.

Maternal TLR4 and NOD2 gene variants, pro-inflammatory phenotype and susceptibility to early-onset preeclampsia and HELLP syndrome

BACKGROUND

Altered maternal inflammatory responses play a role in the development of preeclampsia and the hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome. We examined whether allelic variants of the innate immune receptors Toll-like receptor 4 (TLR4) and nucleotide-binding oligomerization domain 2 (NOD2), that impair the inflammatory response to endotoxin, are related to preeclampsia and HELLP syndrome.

METHODS AND FINDINGS

We determined five common mutations in TLR4 (D299G and T399I) and NOD2 (R702W, G908R and L1007fs) in 340 primiparous women with a history of early-onset preeclampsia, of whom 177 women developed HELLP syndrome and in 113 women with a history of only uneventful pregnancies as controls. In addition, we assessed plasma levels of pro-inflammatory biomarkers C-reactive protein, interleukin-6, soluble intercellular adhesion molecule-1, fibrinogen and von Willebrand factor in a subset of 214 women included at least six months after delivery. After adjustment for maternal age and chronic hypertension, attenuating allelic variants of TLR4 were more common in women with a history of early-onset preeclampsia than in controls (OR 2.9 [95% CI 1.2-6.7]). Highest frequencies for TLR4 variants were observed in women who developed HELLP syndrome (adjusted OR 4.1 [95% CI 1.7-9.8]). In addition, high levels of interleukin-6 and fibrinogen were associated with a history of early-onset preeclampsia. Combined positivity for any of the TLR4 and NOD2 allelic variants and high levels of interleukin-6 was 6.9-fold more common in women with a history of early-onset preeclampsia (95% CI 2.1-23.2) compared to controls.

CONCLUSIONS

We observed an association of common TLR4 and NOD2 gene variants, and pro-inflammatory phenotype with a history of early-onset preeclampsia and HELLP syndrome. These findings suggest involvement of the maternal innate immune system in severe hypertensive disorders of pregnancy.

Maternal infection and risk of preeclampsia: systematic review and metaanalysis

There are lingering questions regarding the association between maternal infection and preeclampsia. Systematic review and metaanalysis was conducted of observational studies that examined the relationship between maternal infection and preeclampsia. Forty-nine studies met the inclusion criteria. The risk of preeclampsia was increased in pregnant women with urinary tract infection (pooled odds ratio, 1.57; 95% CI, 1.45-1.70) and periodontal disease (pooled odds ratio, 1.76; 95% CI, 1.43-2.18). There were no associations between preeclampsia and presence of antibodies to Chlamydia pneumoniae, Helicobacter pylori, and cytomegalovirus, treated and nontreated HIV infection, and malaria. Individual studies did not find a relationship between herpes simplex virus type 2, bacterial vaginosis, and Mycoplasma hominis and preeclampsia. Urinary tract infection and periodontal disease during pregnancy are associated with an increased risk of preeclampsia. More studies are required to verify this as well as to explore whether or not such relationships are causal and, if so, the mechanisms involved.

Association between maternal infections and preeclampsia: a systematic review of epidemiologic studies

OBJECTIVES

A growing body of evidence suggests an association between maternal infection and preeclampsia. To examine the strength of this association, we conducted a comprehensive review of studies published in peer-reviewed journals.

METHODS

Data collection for this review involved Medline, Embase, and Cochrane data base searches of published studies since 1964 on the relationship between maternal infection and preeclampsia. Data were abstracted according to predefined inclusion and exclusion criteria. Study population included women with preeclampsia and normotensive mothers with and without bacterial or viral infections. Altogether, thirty two original studies were identified and evaluated for methodological quality, preeclampsia diagnosis and adjustment for well-known preeclampsia confounders. Pooled odds ratios and 95% confidence intervals, according to infection status, were calculated using DerSimonian-Laird random-effects models. Publication bias was assessed with a funnel plot and Egger's regression asymmetry test.

RESULTS

Sixteen of the 32 studies evaluated were selected for inclusion in the meta-analysis. These studies showed that women with either a bacterial or viral infection were at higher risk of developing preeclampsia, compared to women without infection. Combined results for the 16 studies yielded an OR of 2.1 (95% CI 1.6-2.7). Separate pooled estimates for prospective (OR 2.3, 95% CI 1.7-3.0), case control and retrospective studies combined (OR 2.0, 95% CI 1.4-2.9) yielded similar results. Heterogeneity was significant across overall pooled estimates, case control and retrospective studies (Q(df=20) of 45.7, P = .001; Q(df=10) of 38.7, P < .005, respectively), but not prospective studies (Q(df=9) of 6.5 P = .69).

CONCLUSIONS

In our analysis, any infection (bacterial or viral) was associated with a two-fold higher risk of preeclampsia. This association may provide a potential explanation for preeclampsia-related inflammation.

Clusters of eclampsia in a Nigerian teaching hospital

OBJECTIVE

To describe the pattern of eclampsia between 1995 and 2004 at the Usmanu Danfodiyo University Teaching Hospital, Sokoto, northwestern Nigeria.

STUDY DESIGN

A retrospective cohort of all deliveries and eclamptics seen from 1st January 1995 to 31st December 2004. Clusters of eclampsia were identified using purely temporal scan statistics.

RESULTS

Of 15,318 deliveries during the period, 657(4.29%) had eclampsia. The yearly incidence of eclampsia at the beginning of the study period (1995) was 0.39% but this had increased to 7.0% in 2004 at a background exponential rate best described by quadratic curve fitting prediction model and a forecast curve that predicts an incidence of eclampsia of at least 32.4% of total deliveries by 2009. Temporal clusters occurred in 1996, 2001 and 2003-2004.

CONCLUSION

The incidence of eclampsia is unusually high and is increasing. It has shown 3 clusters in the last 10 years.