Psychological Stress and Hepcidin: A Potential Link to Preterm Birth
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Transcript of Psychological Stress and Hepcidin: A Potential Link to Preterm Birth
Psychological Stress and Hepcidin: A Potential Link to
Preterm BirthMary Dawn Hennessy, RN PhD
Department of Women, Children, and Family Health Science
University of Illinois at Chicago
Carmen Giurgescu, RN PhD WHNPWayne State University
Elizabeta Nemeth, PhDDepartment of Medicine
University of California, Los Angeles
Background and Significance
In 2009, 18% of US African American delivered preterm (<37 weeks)
African Americans have increased psychological stress and higher rates of iron deficiency
Conflicting evidence on link between iron deficiency and preterm birth
Inflammation-mediated iron restriction may be a risk factor, but studies have not made distinction
Spleen
Bone marrow
RBC
Liver
Duodenum
PlasmaFe-Tf
0-5 mg/d
1-2 mg/d 20 mg/d
20 m
g/d
Fpn
Fpn
Fpn
hepcidinhepcidin
hepcidin
Hepcidin: Key Regulator of Iron
Regulation of hepcidin production
Spleen
Bone marrow
RBC
Liver
Duodenum
PlasmaFe-Tf
Fpn
Fpn
Fpn
hepcidinhepcidin
hepcidin
Erythropoietic signal
Iron signal
Inflammation
Aims
Aim 1. Determine if psychological stress and inflammation are correlated with hepcidin levels during pregnancy
Aim 2. Determine if hepcidin levels during pregnancy predict preterm birth
Hypotheses
Hypothesis 1. At any time point during pregnancy, increased psychological stress and/or inflammation will be correlated with increasing hepcidin levels
Hypothesis 2. At any time point during pregnancy, increased hepcidin will be predictive of preterm birth
Sample
88 pregnant self-identified African Americans
Predominately low-income from a large Midwest city
At least 18 years of age Singleton pregnancy 16-22 weeks gestation
Design
Descriptive, longitudinal design Data collected at
– T1 16-22 weeks
– T2 26-32 weeks
– T3 birth
Psychological Stress Measures
Perceived racial discrimination (EOD) Personal resources
– Optimism (LOT)– Self-esteem (RSES)– Coping (PCI)
Emotional stress response– Distress (PGWB)– Anxiety (State Anxiety subscale)– Depression (CES-D)
Serum Measures
Inflammation by multiplex bead immunoassays– Interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-
8, IL-10– TNF-α– C-reactive protein
Hepcidin by ELISA
Results – Demographic and Clinical Characteristics
Characteristic Total sample n = 88, mean (SD)
Age (years) 24 (5.29)
Gestational age at T1 (weeks) 20 (2.50)
Gestational age at T2 (weeks) 29 (2.68)
Gestational age at birth (weeks) 38.8 (2.65)
Birth weight (grams) 3,148 (717)
Low birth weight (< 2,500 grams) 17%
Preterm birth (< 37 weeks) 7%
Single 82%
Unemployed 52%
Household Income < $10,000/year 50%
Note: T1 = 16 - 22 weeks, T2 = 26 - 32 weeks
Results – Psychological Stress, Inflammation and Hepcidin
Hepcidin T1 Hepcidin T2
Experiences of Discrimination- Situations T1
r = 0.22; p = .04
Experiences of Discrimination- Frequency T1
r = 0.25; p = .02
Life Orientation Test T1 r = -0.22; p = .04
IL-8 T2 r = 0.26; p = .05
Note: T1 = 16 - 22 weeks, T2 = 26 - 32 weeksIL = interleukin
Results – Hepcidin and Preterm Birth
Hepcidin ng/mL Full Term Birth
Preterm Birth
Total
T1 < 14 and T2 < 11 29 (44%) 1 (20%) 30 (42%)
T1 < 14 and T2 > 11 5 (8%) 2 (40%) 7 (10%)
T1 > 14 and T2 < 11
21 (32%) 0 (0%) 21 (30%)
T1 > 14 and T2 > 11 11 (17%) 2 (40%) 13 (18%)
Total 66 5 71
Χ2 = 8.56; p = .036
Note: T1 = 16 - 22 weeks, T2 = 26 - 32 weeks
Results – Hepcidin Levels and Preterm Birth
Total Sample
Full Term Birth
Preterm Birth
Test Statistic
Hepcidin
(ng/mL) T1 mean (SD)
17.8 (19.3)n = 88
17.5 (19.7)n = 81
21.5 (13.7)n = 7
F (1,86) = 0.27; p = .60
Hepcidin
(ng/mL) T2
mean (SD)
8.68 (12.2)n = 76
7.88 (11.7)n = 71
20.0 (15.0)n = 5
F (1,74) = 4.88; p = .03
Note: T1 = 16 - 22 weeks, T2 = 26 - 32 weeks
Results – Hepcidin as a Predictor of Preterm Birth
Preterm Birth
Odds Ratio
Standard Error
z-Score p-value 95% CI
Hepcidin T2 1.06 .029 2.07 .039 1.00 – 1.12
Note: CI = Confidence IntervalT2 = 26 - 32 weeks
Conclusions
The iron-regulatory hormone hepcidin is increased in pregnant women with elevated psychological stress and inflammation
Hepcidin may be a useful biomarker of inflammation/stress during pregnancy
Hepcidin-mediated iron restriction may increase the risk for preterm birth
Future Research
Evaluation of hepcidin throughout pregnancy, as elevated or undetectable hepcidin could be used as an early diagnostic tool and an indicator of inflammation-mediated iron restriction or true iron deficiency
Funding Acknowledgements
Midwest Nursing Research Society New Investigator Seed Grant
The University of Illinois at Chicago Dean’s Fund