Maternal serum and fetal cord blood irisin levels in gestational diabetes mellitus
Transcript of Maternal serum and fetal cord blood irisin levels in gestational diabetes mellitus
Maternal serum and fetal cord blood irisin levels ingestational diabetes mellitus
Mehmet Aytac Yuksel a,*, Mahmut Oncul a, Abdullah Tuten a,Metehan Imamoglu a, Abdullah Serdar Acikgoz a,Mine Kucur b, Riza Madazli a
aDepartment of Obstetrics and Gynecology, Cerrahpasa School of Medicine, Istanbul University, Istanbul, TurkeybDepartment of Biochemistry, Cerrahpasa School of Medicine, Istanbul University, Istanbul, Turkey
d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e 1 0 4 ( 2 0 1 4 ) 1 7 1 – 1 7 5
a r t i c l e i n f o
Article history:
Received 28 August 2013
Received in revised form
10 November 2013
Accepted 21 December 2013
Available online 3 January 2014
Keywords:
Gestational diabetes mellitus
Irisin
Cord blood
Maternal
a b s t r a c t
Aim: To investigate the relationship between maternal and cord blood irisin in gestational
diabetes mellitus (GDM).
Methods: Twenty women with GDM and 20 pregnant women with uncomplicated pregnancies
were recruited for this case–control study. Maternal serum irisin and cord blood irisin levels
were measured by enzyme-linked immunosorbent assay kit at the time of birth. The associa-
tion of maternal serum and cord blood irisin levels with metabolic parameters was analyzed.
Results: Women with GDM had significantly lower mean serum irisin levels compared to
control group (258.3 � 127.9 vs. 393 � 178.9 ng/ml, p < 0.05). Mean cord blood irisin levels for
GDM and control groups were not significantly different (357.2 � 248.0 vs. 333.2 � 173.4 ng/
ml, p > 0.05). No significant differences were found in terms of maternal age, gestational
week at birth, BMI at birth, birth weight, neonatal height, systolic and diastolic blood
pressure between the groups as well (p > 0.05). Serum irisin level was negatively correlated
with BMI at birth and HOMA-IR (r = �0.401, p = 0.010; r = �0.395, p = 0.012, respectively). No
correlations between irisin levels and others parameters were found in both groups.
Conclusions: Maternal serum irisin levels of patients with GDM are significantly lower
compared with non-GDM controls. However, no significant difference was found between
cord blood irisin levels of patients with GDM and healthy pregnant women.
# 2014 Elsevier Ireland Ltd. All rights reserved.
Contents available at ScienceDirect
Diabetes Researchand Clinical Practice
journal homepage: www.elsevier.com/locate/diabres
1. Introduction
GDM (gestational diabetes mellitus) has been defined as any
degree of glucose intolerance with onset or first recognition
during pregnancy [1]. GDM, which affects 16–20% of all
pregnancies has serious adverse perinatal outcomes and
increases long-term risk for the development of obesity, type 2
diabetes and cardiovascular disease in both the mother and
* Corresponding author at: Department of Obstetrics and Gynecology, C34098, Turkey. Tel.: +90 532 601 60 58; fax: +90 2124143000.
E-mail address: [email protected] (M.A. Yuksel).
0168-8227/$ – see front matter # 2014 Elsevier Ireland Ltd. All rights
http://dx.doi.org/10.1016/j.diabres.2013.12.025
the offspring [2]. Insulin resistance plays an important role in
the pathogenesis of GDM and despite extensive research, the
mechanisms underlying insulin resistance are not fully
understood [2].
Since it is the largest organ in the body, skeletal muscle
accounts for the majority of glucose uptake in response to
insulin, and is quantitatively the most important site of
insulin resistance. During the past decade, skeletal muscle has
also been identified as a secretory organ and cytokines and
errahpasa School of Medicine, Istanbul University, Fatih, Istanbul
reserved.
d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e 1 0 4 ( 2 0 1 4 ) 1 7 1 – 1 7 5172
other peptides produced and secreted by myocytes are
classified as myokines [3]. These myokines function as
endocrine hormones and regulate the function of various
distant organs. Irisin has recently been identified as an
exercise-induced hormone secreted by skeletal muscle and
has been proposed to mediate the beneficial effects of exercise
on metabolism [4]. Sedentary lifestyle is a major risk factor for
type 2 diabetes mellitus. Randomized controlled trials have
demonstrated that physical activity improves glucose toler-
ance and reduces the risk of type 2 diabetes mellitus [5].
Therefore, it has been speculated that physical exercise may
exert its beneficial effects on energy metabolism through
secreted factors from myocytes such as irisin [3].
Recent studies have shown that circulating irisin levels
were significantly lower in patients with type 2 diabetes
compared to people without diabetes [6,7]. Liu and co-workers
demonstrated that irisin might be positively correlated with
most of the well-known markers of insulin resistance in
people without diabetes [6]. These data show that either the
diabetes itself or the metabolic condition that caused
progression to type 2 diabetes is accompanied by lower
circulating irisin levels in circulation. To date, there are a
paucity of data on irisin and human pregnancy. In the current
study, our aim was to investigate maternal and cord serum
irisin levels in women with GDM and women with uncom-
plicated pregnancies.
2. Material and methods
The Ethics Committee of our university approved the study
protocol (dated February 29, 2013, issue no. 83045809/3709) and
all patients were carefully instructed and signed informed
consent before recruitment. 20 pregnant women with GDM
and 20 controls with uncomplicated pregnancies were
recruited for the study. All recruited patients were selected
randomly from women admitted to the antenatal clinic of our
obstetrics department and had a history of prior cesarean
section deliveries and were planned to deliver with cesarean
section. This criterion was established to exclude any possible
effects of labor on the parameters that evaluated in maternal
blood, described below. Exclusion criteria were as follows:
chronic hypertension, preeclampsia, diabetes mellitus, poly-
hydramnios, presence of any acute or chronic disease, fetal
anomalies, prior renal disease, liver disease, multiple gesta-
tion, history of smoking and chronic alcohol consumption. All
women were screened for GDM with 50 g glucose challenge
test (GCT) at 24th gestational week. The 50-g GCT was carried
out independent of the time of day or any previous meal at
about 24 weeks gestation. An oral glucose tolerance test was
recommended to all patients with a 1-h test result � 140 mg/dl
(7.8 mmol/l). Diagnosis of GDM was established according to
results of 100-gram oral glucose tolerance test (OGTT). Patients
with at least two abnormal values above the cutoff values were
determined to be having an abnormal OGTT result: Fas-
ting � 95 mg/dl (5.3 mmol/l); 1 h, �180 mg/dl (10.0 mmol/l);
2 h, �155 mg/dl (8.6 mmol/l); 3 h, �140 mg/dl (7.8 mmol/l) [8].
Control subjects had normal responses to GCT.
20 patients with GDM received various treatment (diet
therapy, self-monitoring of blood glucose or insulin therapy)
in order to maintain control of blood glucose levels
(venous plasma glucose values were targeted to be
105 mg/dl [5.8 mmol/l] or lower before meals and 120 mg/dl
[6.7 mmol/l] or lower 2 h after meals). Insulin therapy was
administered if blood glucose levels remained above target
levels despite strict diet therapy.
Venous blood samples were collected in the fasting state
before delivery. None of the patients were in labor at the time
of sampling. Umbilical cord blood samples were also collected
immediately after delivery. Blood samples were collected in
tubes and were immediately centrifuged after clotting. The
supernatant serum was kept frozen at �80 8C until assay.
Serum irisin levels were measured using enzyme immunoas-
say (EIA). (Catalog # EK-067-16; Phoenix Pharmaceuticals,
Belmont, CA, USA). The lowest detectable concentration of
irisin was 6.8 ng/ml, with intra- and interassay coefficients of
variation were <%10 and %15, respectively. Glucose, insulin,
and HbA1c were determined with standard laboratory
methods. Insulin resistance was estimated by homeostasis
model assessment of insulin resistance (HOMA-IR) [9]. Home-
ostasis model assessment (HOMA) was calculated according to
the following formula: HOMA-IR = [fasting glucose (mmol/
l) � fasting insulin (mU/ml)]/22.5. In women with gestational
diabetes who were on insulin therapy, HOMA-IR was
determined before initiation of insulin therapy. Maternal
body mass index (BMI) values (kg/m2) were calculated prior to
delivery as the ratio of the weight (kg) to the square of the
height (m).
All analyses were performed using the Statistical Package
for the Social Sciences (SPSS) software version 18.0. Kolmo-
gorov–Smirnov test was used to assess normality of distribu-
tion of variables. Data are presented as mean � standard
deviation. Mean values between the groups were compared by
Student t test. Comparison between groups was performed
using Mann–Whitney U-test or independent samples t-test.
Spearman’s correlation coefficient was used to determine the
relationship between the variables. All reported confidence
interval (CI) values are calculated at the 95% level. A p
value < 0.05 was considered statistically significant.
3. Results
Clinical characteristics and biochemical parameters of each
group are shown in Tables 1 and 2. No significant differences
were found between the groups in terms of mean maternal
age, gestational age at birth, BMI, birth weight, neonatal
height, systolic and diastolic blood pressures (p > 0.05).
Mean maternal serum HOMA-IR, fasting glucose and
insulin levels of women with GDM at the time of delivery
were significantly higher than the control group (Table 2).
Mean maternal serum irisin level of women with GDM was
significantly lower than the control group (258.3 � 127.9 vs.
393 � 178.9 ng/ml, p: 0.009) (Table 2 and Fig. 1). Irisin levels in
cord blood were not statistically different among groups
(357.2 � 248.0 vs. 333.2 � 173.4 ng/ml, p: 0.735) (Table 2).
Among women with GDM, 8 had insulin therapy and 12
were treated with diet alone. Clinical and biochemical
characteristics of GDM patients treated with insulin and
managed by diet are shown in Table 3. Mean maternal serum
Table 1 – The clinical characteristics of women diagnosed with gestational diabetes and normal controls.
GDM (n: 20) Control (n: 20) p value
Age (year) 34.8 � 4.11 33.0 � 5.35 0.242
Gestational age at birth (week) 37.4 � 2.7 38.0 � 1.1 0.862
Maternal weight (kg) 82.6 � 11.0 76.4 � 11.1 0.091
Maternal height (cm) 163 � 6.3 164.1 � 7.8 0.758
BMI at birth (kg/m2) 31.4 � 5.3 28.5 � 4.4 0.174
Birth weight (g) 3261 � 755 3366 � 436 0.883
Neonatal height (cm) 49.5 � 4.1 50.2 � 1.6 0.758
SBP (mmHg) 119 � 16.0 109.5 � 10.9 0.060
DBP (mmHg) 73.5 � 8.7 69.0 � 7.8 0.157
Data are presented as mean � standard error of mean (SEM). BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure.
Statistically significant: p < 0.05.
Table 2 – Biochemical characteristics women diagnosed with gestational diabetes and normal controls.
GDM (n: 20) Control (n: 20) p value
Fasting glucose (mg/dl) 90.9 � 21.1 74.5 � 12.9 0.012
HOMA-IR 2.63 � 1.0 1.44 � 0.53 0.000
HbA1c (%) 5.7 � 1.9 5.11 � 0.36 0.367
Insulin (mU/l) 12.4 � 5.1 8.19 � 2.0 0.003
Serum irisin (ng/ml) 258.3 � 127.9 393 � 178.9 0.009
Cord irisin (ng/ml) 357.2 � 248.0 333.2 � 173.4 0.735
Cord glucose (mg/dl) 70.7 � 8.6 67.3 � 9.8 0.217
Data are presented as mean � standard error of mean (SEM). HOMA-IR, homeostatic model assessment of insulin resistance. Statistically
significant: p < 0.05.
d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e 1 0 4 ( 2 0 1 4 ) 1 7 1 – 1 7 5 173
irisin and cord irisin levels were not significantly different
between women with GDM on insulin therapy and those
treated with diet alone (p > 0.05) (Table 3).
Maternal serum irisin levels were negatively correlated with
BMI and HOMA-IR values (r = �0.401, p = 0.010; r = �0.395,
p = 0.012, respectively) (Fig. 2). In addition, maternal mean
serum irisin levels were not found to be associated with age,
gestational week at birth, birth weight, HbA1c, glucose, insulin
and cord irisin levels (r = �0.087, p = 0.596; r = �303, p = 0.058;
r = �0.150, p = 0.357; r = 0.063, p = 0.764; r = �0.264, p = 0.100;
r = �0.236, p = 0.142; r = �0.013, p = 0.936, respectively) (Table 4).
Data are pres ented as mean ±
Fig. 1 – Maternal irisin levels in w
4. Discussion
Association between irisin and various diseases such as
obesity, anorexia nervosa, type 2 diabetes, insulin sensitivity
and chronic kidney disease has been studied [6,7,10,11].
However, to the best of our knowledge, this is the first study
to investigate the relationship between irisin and pregnancy.
Maternal serum irisin levels were significantly lower in
pregnant women with GDM compared to control group. This
result suggests that serum irisin levels might be introduced as
sta nda rd error of mean (SEM)
omen with and without GDM.
Table 3 – The clinical and biochemical characteristics of GDM patients treated with insulin and managed by diet.
Management by diet (n: 12) Insulin treatment (n: 8) p value
Age (year) 34.0 � 3.91 35.8 � 4.42 0.258
BMI at birth (kg/m2) 30.5 � 4.46 32.8 � 6.45 0.487
Gestational age at birth (week) 37.3 � 3.39 37.6 � 1.76 0.528
Birth weight (g) 3110.0 � 863.0 3487.5 � 529.3 0.395
Fasting glucose (mg/dl) 87.7 � 21.5 95.6 � 20.9 0.334
HOMA-IR 2.45 � 0.83 2.89 � 1.38 0.512
HbA1c (%) 5.53 � 1.37 6.05 � 2.48 0.954
Insulin (mU/l) 12.1 � 5.07 12.8 � 5.66 0.643
Serum irisin (ng/ml) 267.0 � 110.7 245.3 � 157.5 0.280
Cordon irisin (ng/ml) 387.0 � 250.7 312.5 � 253.5 0.396
Cordon glucose (mg/dl) 68.2 � 9.38 74.5 � 6.07 0.141
Data are presented as mean � standard error of mean (SEM). BMI, body mass index; HOMA-IR, homeostatic model assessment of insulin
resistance. Statistically significant: p < 0.05.
Table 4 – Correlations between maternal serum irisinlevels and all the other parameters in whole groups.
Maternal serum irisin levels
r p
Maternal age �0.087 0.596
BMI at birth �0.401 0.010*
Gestational week at birth �0.303 0.058
Birth weight �0.150 0.357
HbA1c 0.063 0.764
Glucose �0.264 0.100
Insulin �0.236 0.142
HOMA-IR �0.395 0.012*
Cord irisin �0.013 0.936
BMI, body mass index; HOMA-IR, homeostatic model assessment
of insulin resistance. Statistically significant: p < 0.05.* Significant difference.
d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e 1 0 4 ( 2 0 1 4 ) 1 7 1 – 1 7 5174
a prospective and novel marker for GDM and decreased levels
of irisin might be indicative of GDM. There was no significant
relationship between GDM and cord irisin levels. Irisin has
been proposed to be involved in mediating the beneficial
effects of exercise on metabolism [4]. In culture and mouse
Fig. 2 – Correlation between maternal serum irisin
models, expression of FNDC5 gene has been proposed to
stimulate the production of irisin, thus leading to an increase
in uncoupling protein 1 (UCP1) levels which induce browning
of subcutaneous adipocytes and thermogenesis [4]. Improve-
ment in glucose tolerance of mice fed a high-fat diet occurs
when circulating levels of irisin increased 3–4 fold [4].
Therefore, brown fat has been demonstrated to induce effects
against diabetes and obesity in murine models [12] as well as
humans [13].
As a PGC-1a activated messenger of myocytes, irisin is
involved in the association between sedentary lifestyle and
obesity and diabetes [3,4,14,15]. The relationship between
irisin and type 2 diabetes has been evaluated in recent studies
[6,7]. It has been suggested that lower levels of circulating
irisin is associated with diabetes itself or the metabolic
condition that caused progression to type 2 diabetes. Previous
studies also investigated the role of PGC-1a in the pathogen-
esis of women with PCOS, type 2 diabetes and their offspring.
Studies in humans revealed that PGC-1a expression and its
activity were significantly down-regulated in skeletal muscles
in type 2 diabetes [16]. Our results show that circulating irisin
levels are significantly lower in women with GDM, and these
levels and BMI and HOMA-IR in all patients.
d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e 1 0 4 ( 2 0 1 4 ) 1 7 1 – 1 7 5 175
data are consistent with the available data. Therefore, it is
reasonable to hypothesize that lower level of circulating irisin
observed in our study might be secondary to impaired PGC-1a
expression and function in muscles in patients with GDM.
The effects of irisin on energy metabolism is controversial
[17]. Liu et al. have reported a positive correlation between
circulating irisin levels and BMI values in people without
diabetes. However, the same study also showed no association
between irisin expression from myocytes and BMI, fasting
insulin and fasting blood glucose (FBG) in patients with
diabetes [6]. Positive correlations between circulating irisin
levels and BMI in people without diabetes were shown in the
studies of Stengel et al. and Huh et al. [10,18]. In contrast, a
very recent study suggested that circulating irisin correlated
negatively with BMI, waist–hip ratio and fat mass in men. Even
after adjustment for age, waist–hip ratio and insulin sensi-
tivity; circulating irisin was still lower in overweight and obese
men without diabetes [19]. Our study showed that maternal
serum irisin levels were negatively correlated with BMI and
insulin resistance. Reasons for these discrepancies could be
the gender-differences, but this paradox might also the result
of a disassociation between FNDC5 expression and circulating
irisin under some conditions.
Irisin in fetal cord blood has not been evaluated so far. We
found no significant difference in cord blood irisin levels of
patients with GDM compared to control group. In fact, we have
no data about the placental absorption of maternal irisin. In
addition to this, normal maternal glucose levels were
successfully achieved in women with GDM in this study.
These facts may explain fetal irisin levels. Indeed, further
evaluation of fetal irisin in GDM patients with uncontrolled
glycemic profiles may contribute to an elaboration of fetal
irisin and its association with GDM.
The inability to measure the effect of fetal insulin concen-
trations on fetal irisin levels and the relatively small population
can be listed as the limitations of the study. Therefore, further
studies are needed to investigate the role of irisin in the
pathogenesis of GDM. In conclusion, maternal serum irisin
levels are lower in the patients with GDM. It remains possible
that GDM may affect PGC-1a expression or functions in
muscles. Furthermore, maternal plasma irisin levels are
negatively associated with BMI and insulin resistance.
Conflict of interest
No conflict of interest.
r e f e r e n c e s
[1] ACOG Practice Bulletin. Clinical management guidelines forobstetrician-gynecologists. Number 30, September 2001
(replaces Technical Bulletin Number 200, December 1994).Gestational diabetes. Obstet Gynecol 2001;98:525–38.
[2] Catalano PM, Kirwan JP, Haugel-de Mouzon S, King J.Gestational diabetes and insulin resistance: role in short-and long-term implications for mother and fetus. J Nutr2003;133:1674S–83S.
[3] Pedersen BK, Febbraio M.A.. Muscles exercise and obesity:skeletal muscle as a secretory organ. Nat Rev Endocrinol2012;8:457–65.
[4] Bostrom P, Wu J, Jedrychowski MP, Korde A, Ye L, Lo JC,et al. A PGC1-alpha-dependent myokine that drives brown-fat-like development of white fat and thermogenesis.Nature 2012;481:463–8.
[5] Hojlund K, Bostrom P. Irisin in obesity and type 2 diabetes. JDiabetes Complications 2013;27:303–4.
[6] Liu JJ, Wong MD, Toy WC, Tan CS, Liu S, Ng XW, et al. Lowercirculating irisin is associated with type 2 diabetes mellitus.J Diabetes Complications 2013;27:365–9.
[7] Choi YK, Kim MK, Bae KH, Seo HA, Jeong JY, Lee WK, et al.Serum irisin levels in new-onset type 2 diabetes. DiabetesRes Clin Pract 2013;100:96–101.
[8] Carpenter MW, Coustan DR. Criteria for screening tests forgestational diabetes. Am J Obstet Gynecol 1982;144:768–73.
[9] Matthews DR, Hosker JP, Rudenski AS, Naylor BA, TreacherDF, Turner RC. Homeostasis model assessment: insulinresistance and beta-cell function from fasting plasmaglucose and insulin concentrations in man. Diabetologia1985;28:412–9.
[10] Stengel A, Hofmann T, Goebel-Stengel M, Elbelt U, Kobelt P,Klapp BF. Circulating levels of irisin in patients withanorexia nervosa and different stages of obesity—correlation with body mass index. Peptides 2013;39:125–30.
[11] Wen MS, Wang CY, Lin SL, Hung KC. Decrease in irisin inpatients with chronic kidney disease. PLoS One2013;8:e64025.
[12] Seale P, Conroe HM, Estall J, Kajimura S, Frontini A,Ishibashi J, et al. Prdm16 determines the thermogenicprogram of subcutaneous white adipose tissue in mice. JClin Invest 2011;121:96–105.
[13] Enerback S. Human brown adipose tissue. Cell Metab2010;11:248–52.
[14] Kelly DP. Medicine. Irisin, light my fire. Science2012;336:42–3.
[15] Villarroya F. Irisin, turning up the heat. Cell Metab2012;15:277–8.
[16] Liang H, Ward WF. PGC-1alpha: a key regulator of energymetabolism. Adv Physiol Educ 2006;30:145–51.
[17] Timmons JA, Baar K, Davidsen PK, Atherton PJ. Isirisin a human exercise gene? Nature 2012;488:E9–10.discussion E-1.
[18] Huh JY, Panagiotou G, Mougios V, Brinkoetter M, VamviniMT, Schneider BE, et al. FNDC5 and irisin in humans: I.Predictors of circulating concentrations in serum andplasma and II. mRNA expression and circulatingconcentrations in response to weight loss and exercise.Metabolism 2012;61:1725–38.
[19] Moreno-Navarrete JM, Ortega F, Serrano M, Guerra E, PardoG, Tinahones F, et al. Irisin is expressed and produced byhuman muscle and adipose tissue in association withobesity and insulin resistance. J Clin Endocrinol Metab2013;98:E769–78.