Adiponectin is a harmone produced abundantly by adipose tissue. It is 244- aminoacid polypeptide is present in large quantities in serum. It plays very important role in regulation of insulin resistance, atherosclerosis, inflammatory responses and angiogenesis. Serum adiponectin concentrations inversely related to insulin resistance, obesity, dyslipidimia and hypertension. During pregnancy, women gain  body fat and therefore adiponectin levels are reported to fall. Preeclampsia is associated with with hypertension due to vasoconstriction and widespread endothelial damage. Adiponectin suppresses the macrophage- to- foam cell transformation and inhibits the expression activity of the class A macrophage scavenger receptor and thereby having anti atherosclerotic role. It also acts by suppressing macrophage production of pro inflammatory cytokines and prevents activation of the nuclear transcription factor NF-kB.¹

Preeclampsia is the one of the most common and serious medical disorder of pregnancy which contributing significantly to  both  maternal  and neonatal    morbidity    and  mortality.PIH    affecting approximately  5-7%  of  pregnancies  and  in  India  the incidence  of PIH is from 5% to 15%. The Hypertensive disorders complicating pregnancy  form one of the deadly triads of    maternal    death    along    with    sepsis    and haemorrhage.  PIH  has  been  divided  into  four categories four categories as recommended  by  the  National  High  Blood  Pressure Education   Program   Working   Group   on   High   Blood Pressure  in  Pregnancy Gestational  hypertension,  Preeclampsia and Eclampsia,  Chronic  hypertension  of  any aetiology   and   preeclampsia   superimposed   on   chronic hypertension.  Preeclampsia  is defined asBP>140/90 or higher, measured on at least two occasions, 2 h apart after 20  weeks  of  gestation and proteinuria(300mg  or more  of urinary  protein  for  24hrs  or  100mg/dl  or  more  in  at least two  random  urine  specimens  collected  6  or  more   hours apart). Severe preeclampsia when bp of 160/110 or higher measured  on  two  occasions  at  least  6  h  apart  and Proteinuria  of  >5  g  in  24  h  (or proteinuria  equal  to  or greater than +3 as measured by urinary reagent strips in at least two random specimens collected 4h apart )or oliguria <  400  ml  in  24  h,  or  cerebral  or  visual  disturbances.²

 Hypertension,   proteinuria, excessive weight   gain   and oedema are classic clinical manifestations of preeclampsia. Most maternal deaths are associated with with complications of severe preeclampsia such as cerebrovascular hemorrhagic, renal or hepatic failure and HELLP syndrome. Preeclampsia is also associated with exaggerated intravascular inflammatory response, insulin resistance, obesity, hyperlipidemia. The underlying mechanism suggesting this correlation 1) excess of adipose tissue can produce hypoxia environment by increasing the concentration of glyosylated Haemoglobin and decreasing the affinity for oxygen. This relative hypoxemia leads defective plancental development. 2) subclinical inflammation is always linked to obesity since more body fat is associated with raised levels of cytokines and subclinical inflammation. An exaggerated inflammatory response is one of the characteristics of preeclampsia, and thus patients with an inflammatory response in early pregnancy  are more prone to developed preeclampsia. patients destined to develop preeclampsia are characteristically have low serum adiponectin.³

There are limited data and inconsistent findings regarding association between plasma adiponectin and pathology of preeclampsia. By studying this link we will be able to understand etiology, consequences of preeclampsia earlier and in better way. We choose to focus patients with preeclampsia because pathological alterations are more likely to be present in this subset of patients.

AIM: the aim of the study was to estimate level of serum adiponectin in preeclampsia patients.

The hospital based observational prospective study conducted at department of Obstetrics and Gynaecology, SPMC Bikaner. It was conducted including patients with preeclampsia (n=45) and pregnant normotensive females (n=45).The duration of study was 1 year (1st March 2023 to 31 March 2024). The study was approved by research and ethics committee of SPMC Bikaner.

Patients aged ≥ 18 years, having gestational age of >20wk, having hypertension in pregnancy and willing to participate were included in study as cases. Patients with any infectious disease, with intake of alcohol, substance abuse and smoking patients in labour, Placental abruption, twin pregnancy, with any, coagulopathy or coronary heart disease, having past history of Tuberculosis, Diabetes mellitus, Asthma and other chronic illness and refuse to give consent  were excluded from study.

Controls were randomly selected having gestational age of >20wk and not having PIH, matched with cases attendeing to Gynae unit 4 OPD or inpatient at Department of Obstetrics and Gynaecology SPMC Bikaner.

Procedure:

Selected participants was interviewed using a pretested semi-structured interviewer administered questionnaire. The questionnaire will include question related to socio-demographic background and clinical examination. Samples collected in the serum separator tube.After clotting for 2hrs at room temperature,then centrifuged at 1000 X g for 20 minutes. Samples stored at room temperature -20*C. Plasma wasprepare by centrifugation and stored at -70C until it could be analysed .Glucose concentrations analysed on glucose analyser. Serum adiponectin and insulin levels was measured using enzyme-linked immunosorbent assays.

CALCULATIONS

Adiponectin is present in plasma 3-30 ug / ml. It is also related to BMI . Females with

BMI <25.5 have seurm adiponectin 5 to 37 ug/ml.

BMI <25.5-30.5  have seurm adiponectin 5 to 28 ug/ml.

BMI >30.5 have seurm adiponectin 2 to 20 ug/ml.

PROCEDURE FOLLOWED- ELISA plate consisting of 96 (12X8 wells) under all aseptic conditions wells were determine wells for diluted, standard, blank and sample. Prepare 7 wells for standard ,1 for blank. Add 100 microlitre each of standard working solution. Plate was incubated for 80 minutes at 37*C.Pour out liquid from each well.Aspirate the solution and wash with 200 microlitre of 1X wash solution to each well and let it sit for 1-2 mins. Remove the remaining liquid from all wells. Totally wash 3 times. Invert the plate and blot it against absorbant paper. 100 microlitre of biotinylated antibody working solution added to each value, all wells covered with plate and incubated for 15 minutes at 37*C. Aspiration, wash process repeated for total 3 times. Streptavidin-HRP working solution added to each well and incubated for 15 minutes at 37*C. Aspiration, wash process total 5 times repeated when 90 microlitre. Then 90 microlitre of TMB substrate solution added to each well. Plate was incubated for 20 mins at 37*C in the dark. The liquid turned to blue on addition of TMB substrate solution. The liquid turn to yellow on addition of stop reagent, placed in ELISA reader machine. Then concentration measured at 450nm optical density of serum adiponectin calculated.

The mean age group in hypertensive patients was 25.52±3.75and in normotensive patients was26.82±4.4. Mean BMI in group A was 29.32±3.14 kg/m² and in group B mean BMI was 24.98 ± 4.64 kg/m². Mean systolic BP in group A was 160.4 ± 12.18mm of Hg and in group B mean systolic BP was 118.26±10.62 mm of Hg and Mean diastolic BP in group A was 98.4 ± 8.81 mm of Hg and in group B mean diastolic BP was 76.95 ± 7.76mm of Hg. Hypertensive disorders of pregnancy are more common in primigravida. The mean level of the serum Adiponectin in cases  was   8.21±1.42 pg/ml and in control was mean Serum Adiponectin was29.1±12.80 pg/ml and this difference was found statistically significant (p<0.005). Furthermore in preeclampsia patients having more BP were associated with more low levels of serum adiponectin.Hypertensive patients had low levels of serum adiponectin ,than normotensive patients. Obesity was found to be  inversely realated to serum levels of serum adiponectin.

1. Socio- demographic profile

Shows correlation  of serum adiponectin with parameters of Hypertensive disorders of pregnancy. In group A cases had mean systolic blood Pressure of 158.2± 5.8 and mean Diastolic blood pressure of 104.2 ± 8.01 had  serum adiponectin <30 pg/ml.  In group        B women had mean systolic blood Pressure of  149.11 ± 7.81 and mean Diastolic blood pressur 100.5 ± 8.46 had serum adiponectin> 30 pg/ml.. This difference was found statistically significant (p<0.005).

Table 2 Distribution of cases according to Serum adiponectin

Fig. 1 Mean Adiponectin values in both groups

Mean Serum Adiponectin in group A was 8.21±1.42 pg/ml while in group B mean serum Adiponectinwas. 29.1 ± 12.80 pg/ml and this difference was found statistically significant (p<0.005).

Preeclampsia is defined as hypertension after 20 gestational weeks with proteinuria, organ damage, or uteroplacental dysfunction. Gestational hypertension is similar to preeclampsia; however, the condition is defined as hypertension alone after 20 gestational weeks. Pregnancy induced hypertension is a major contributors to maternal and perinatal morbidity and mortality. Pregnant women from Bikaner and periphery were being referred to our facility. Till date no markers were available to predict hypertension disorders in pregnancy. This study was conducted to assess level of serum adiponectin as early predictors of hypertensive disorders of pregnancy.

Mean age group in group A was 25.52±3.75 and in group B mean age group was 26.82±4.4. Both groups are comparable in regards to age of patients. Similarly Hélène Caillon et al. (2018)⁴ and Ahmed Tijani Bawah et al. (2020)⁵ found that the mean age of those with PE was higher than those without PE. Hypertensive disorder of pregnancy increases with age.

In group A 27 (60.00%) were primigravida and 18 (40.00%) were multigravida. In group B 25 (55.56.%) were primigravida and 20(44.44%) were multigravida (P>0.05). Similarly Clare B. Kelly (2017)⁶ found that mean gravida was 1.3 ± 0.7 in hypertensive group, and 1.3 ± 0.7 in non hypertensive group. Also J Tavakkol Afshari et al (2005)⁷ Gravidity was 2.3 ± 1.4 in normotensive groups & 2.2 ± 1.7 in preeclampsia group. According to WHO, being  pregnant for the first time, adolescent pregnancy and twin pregnancy are risk factors for hypertensive disorders of pregnancy.  

Mean BMI in group A was 29.32 ± 3.14 kg/m² while in group B mean BMI was 24.98 ± 4.64 kg/m². This difference was found statistically insignificant (p>0.05). Excess of adipose tissue causes hypoxic environment by increasing concentration of glycosylated Hb and thus decreasing affinity for oxygen. This causes subclinical inflammation, abnormal placentation which contributes to development of HDP in obese female. Ahmed Tijani Bawah et al. (2020)⁷ found that BMI was also significantly higher in those who developed PE than in those who did not (32.63 vs 24.99 kg/m2; P < 0.0001).

In our study, mean systolic BP in group A was 160.4 ± 12.18mm of Hg and  in group B mean systolic BP was 118.26 ± 10.62mm of Hg. This difference was found statistically significant (p<0.05). Mean diastolic BP in group A was 98.4 ± 8.81mm of Hg and in group B mean diastolic BP was 76.95 ± 7.76mm of Hg (p<0.05). Similarly Clare B. Kelly (2017)⁶ observed that Systolic BP was 113.1 ± 12.4 in hypertensive group and 109.4 ± 9.6 in non hypertensive group. Diastolic BP was 66.6 ± 9.0 in hypertensive group and 63.8 ± 8.1 in non hypertensive group. (p<0.05).

In our study, mean Serum Adiponectin in group A was 8.21±1.42pg/ml and in group B mean Serum Adiponectin was, 29.1 ± 12.80 pg/ml. This difference was found statistically significant (p<0.005). Adiponectin plays role in the regulation of insulin resistance, atherosclerosis, inflammatory responses and angiogenesis was seen. In addition to the insulin-sensitizing property of adiponectin, this adipokine has a protective effect against atherosclerosis. Adiponectin suppresses the macrophage-to-foam cell transformation⁸ and inhibits the expression and the activity of the class A macrophage scavenger receptor. Several reports have highlighted the anti-inflammatory properties of adiponectin, including the suppression of macrophage production of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α)^9,10 interferon-gamma (IFN-γ)¹¹ and interleukin-6 (IL-6).  Patients destined to develop preeclampsia are characterized by first trimester low serum concentrations of adiponectin and high serum concentrations of this adipokine after diagnosis, during labor. Similarly Clare B. Kelly et al. (2017)⁶ Total adiponectin decreased progressively throughout pregnancy in all groups (DM+PE+, p < 0. 01; DM+PE–, p < 0.001; DM–, p < 0.05). Also Ahmed Tijani Bawah et al. (2020)⁷ found that adiponectin was significantly lower 39.3 in the PEs compared to the non PEs 83.6.(p<0.0001)

In our study, In group A cases had mean systolic blood Pressure of 158.2 ± 5.8 mm of Hg and mean Diastolic blood pressure of 104.2 ± 8.01 mm of Hg had  serum adiponectin  <30 pg/ml.  In group B women had mean systolic blood Pressure of  149.11 ± 7.81 mm of Hg and mean Diastolic blood pressure 100.5 ± 8.46 mm of Hg had serum adiponectin > 30 pg/ml. This difference was found statistically significant (p<0.005). Adiponectin have antiinflamatory, antiatherogenic and angiogenic properties. In hypertensive disorderes of pregnancies low adiponectin levels are associated with impaired endothelial dependent vasodialatation. In hypertensive patients there is decreased expression of adiponectin receptors.

In group A mean BMI was 26.98 ± 2.15 and in group B was 23.58 ± 1.12. This difference was found statistically significant (p<0.005) adiponectin levels in serum inversely related to body fat and increases with fat loss during pregnancy. Women gain fat and therefore adiponectin levels falls.

We concluded that maternal serum adiponectin levels are significantly lower in preeclamptic patients. However adiponectin is also found to be inversely associated with obesity. Finally we concluded that adiponectin can be used as an early predictor of preeclampsia.

Conflict of interest: Nil

Financial support: Nil

Acknowledgement: Dr Sanjay Kochar, Senior professor and head of medicine and head of MDRU unit.

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