Investigation of serum apelin-13 and apelin-36 concentrations in pregnancies complicated by preeclampsia; a prospective case-control study

Figures & data

Table 1. Demographic characteristics of control and preeclampsia groups.

		Control (n = 40)	Preeclampsia (n = 40)
		Mean ± SD	Mean ± SD	p-value
Age (years)		29.3 ± 4.4	30.8 ± 5.0	0.165*
BMI at sampling (kg/m^2)		30.2 ± 3.7	30.9 ± 5.1	0.462*
Weight gain during pregnancy (kg)		11.8 ± 5.6	14.2 ± 5.97	0.068*
Parity	Nulliparous n (%)	18 (45)	20 (50)	0.823**
	Multiparous n (%)	22 (55)	20 (50)

*Independent t-test; **Chi-Square test; BMI, body mass index.

Table 2. Comparison of control and preeclampsia groups in terms of laboratory and ultrasound findings.

	Control (n = 40)	Preeclampsia (n = 40)
	Median (IQR)	Median (IQR)	p-value
Systolic blood pressure (mmHg)	110 (10)	150 (21)	0.000*
Diastolic blood pressure (mmHg)	65 (10)	100 (18)	0.000*
Mean arterial pressure (mmHg)	77 (10)	117 (16)	0.000*
Protein/Creatinine ratio in a spot urine sample	0.13 (0.07)	0.72 (1.01)	0.000*
AST (U/L)	17 (7)	20.5 (18)	0.075*
ALT (U/L)	9.5 (7)	12 (20)	0.069*
Platelet count (10^3/uL)	221.5 (63)	202.5 (78)	0.130*
Maternal epigastric subcutaneous adipose tissue thickness (mm)	10.3 (4.4)	13.9 (8.3)	0.007*
Maternal periumbilical subcutaneous adipose tissue thickness (mm)	13.3 (8.3)	18.5 (9.7)	0.011*
Umbilical artery Doppler PI	0.86 (0.27)	1.1 (0.33)	0.000*
Umbilical artery Doppler RI	0.56 (0.13)	0.66 (0.16)	0.000*
Umbilical artery Doppler S/D	2.31 (0.47)	2.66 (0.69)	0.000*
	n (%)	n (%)
Presence of Uterine Artery Notch (one or both sides)	0 (0)	20 (50)	0.000**
IUGR	0 (0)	4 (10)	0.116**

*Man Whitney U test; **Chi-Square test; AST, aspartate aminotransferase; ALT, alanine aminotransferase, IUGR, intrauterine growth restriction.

Table 3. Comparison of control and preeclampsia groups in terms of perinatal outcomes.

		Control (n = 40)	Preeclampsia (n = 40)
		n (%)	n (%)	p-value
Thrombocytopenia		0 (0)	4	0.116*
HELLP syndrome		0 (0)	3	0.241*
Visual symptoms		0 (0)	8	0.005*
Pulmonary edema		0 (0)	0	–
Eclampsia		0 (0)	0	–
Placental abruption		0 (0)	2	0.457*
Mode of delivery	Vaginal birth	25 (62.5)	7 (17.5)	0.000*
	Cesarean section	15 (37.5)	33 (82.5)
Preterm delivery		0 (0)	21 (52.5)	0.000*
Gender of the newborn	Female	24 (60)	21 (52.5)	0.520*
	Male	16 (40)	19 (47.5)
NICU Admission		1 (2.5)	24 (60)	0.000*
		Median (IQR)	Median (IQR)	p-value
Gestational age at delivery (weeks)		38 (3)	37 (5)	0.000**
Birth weight (gr)		3305 (633)	2457 (1671)	0.000**
1st minute Apgar score		8 (1)	7 (3)	0.003**
5th minute Apgar score		10 (1)	9 (2)	0.000**

*Chi-Square test; **Man Whitney U test; NICU, neonatal intensive care unit.

Figure 1. Maternal serum Apelin-13 concentration of control and preeclampsia groups.

Figure 2. Maternal serum Apelin-36 concentration of control and preeclampsia groups.

Table 4. Comparison of control and preeclampsia groups in terms of maternal serum apelin-13 and apelin-36 concentrations.

	Control (n = 40)	Preeclampsia (n = 40)
	Median (IQR)	Median (IQR)	p-value
Gestational week at blood sampling	36.5 (3)	34 (5)	0.077
Apelin-13 (pg/ml)	1954 (1616.2)	1635 (965.1)	0.005
Apelin-36 (pg/ml)	1042.8 (1209.1)	735.7 (478.2)	0.001

Man Whitney U test.

Figure 3. ROC analysis for the sensitivity, specificity, and positive and negative predictive value of apelin-13 and apelin-36 in preeclampsia.

Table 5. Comparison of control, mild preeclampsia, and severe preeclampsia groups in terms of maternal serum apelin-13 and apelin-36 concentrations.

	Control (n = 40)	Mild Preeclampsia (n = 24)	Severe Preeclampsia (n = 16)
	Median (IQR)	Median (IQR)	Median (IQR)	p-value	Post Hoc
Gestational week at blood sampling	36.5 (3)	35.5 (5)	33 (7)	0.061	–
Apelin-13 (pg/ml)	1954 (1616.2)^a	1635.3 (1019.4)^b	1514.9 (1005.3)^c	0.020	a > c (p = 0.008)
Apelin-36 (pg/ml)	1042.8 (1209.1)^a	691.9 (495.2)^b	762.3 (696.6)^c	0.003	a > b (p = 0.001) a > c (p = 0.009)

Kruskal Wallis test.

Table 6. Comparison of control, early-onset preeclampsia, and late-onset preeclampsia groups in terms of maternal serum apelin-13 and apelin-36 concentrations.

	Control (n = 40)	Early-onset Preeclampsia (n = 25)	Late-onset Preeclampsia (n = 15)
	Median (IQR)	Median (IQR)	Median (IQR)	p-value	Post Hoc
Gestational week at blood sampling	36.5 (3)^a	33.0 (4)^b	37.0 (3)^c	0.000	a > b (p = 0.001) c > b (p = 0.000)
Apelin-13 (pg/ml)	1954 (1616.2)^a	1511 (1161.7)^b	1766.6 (806.1)^c	0.016	a > b (p = 0.006)
Apelin-36 (pg/ml)	1042.8 (1209.1)^a	688.1 (287.8)^b	1013.7 (818.6)^c	0.001	a > b (p = 0.000)

Kruskal Wallis test.

Table 7. Correlation between maternal serum apelin-13 and apelin-36 concentrations and preeclampsia related parameters.

	Maternal serum apelin-13		Maternal serum apelin-36
	r	p	r	p
Age (Years)	0.026	0.875	−0.012	0.939
BMI (kg/m^2)	−0.057	0.725	0.211	0.191
Parity	−0.212	0.190	−0.151	0.352
Weight gained during pregnancy (kg)	−0.069	0.673	0.117	0.474
Maternal epigastric subcutaneous adipose tissue thickness (mm)	−0.241	0.134	0.224	0.165
Maternal periumbilical subcutaneous adipose tissue thickness (mm)	−0.162	0.317	0.167	0.302
Umbilical artery Doppler PI	0.047	0.772	0.110	0.501
Umbilical artery Doppler RI	0.021	0.897	0.048	0.771
Umbilical artery Doppler S/D	0.006	0.971	0.006	0.971

Pearson correlation.

Data availability statement

Data supporting the findings of this study is available via the OSFHOME data repository with the 10.17605/OSF.IO/4CG8R DOI identifier.