Overview

Prenatal development determines health throughout life, and the placenta plays a critical role in supplying the fetus with nutrients and oxygen. Carefully regulated interactions between the placenta and the lining of the mother’s uterus are crucial to normal placental development and a healthy pregnancy. Abnormalities in these interactions very early in pregnancy can lead to miscarriage or to complications that are not apparent until months later, when they may threaten the lives of the fetus and the mother. Understanding the etiology of such placental complications could facilitate monitoring and preventative treatment.

Various diseases of pregnancy are associated with unusual maternal blood levels of proteins of the insulin-like growth factor pathway, but the mechanisms responsible for these associations are unknown. I am examining the roles that these proteins play in the regulation of the early growth and development of the placenta.

Publications

Effects of high-fat diets on fetal growth in rodents: a systematic review
Reproductive Biology and Endocrinology
Julian K. Christians and Kendra I. Lennie and Lisa K. Wild and Raajan Garcha
DOI: 10.1186/s12958-019-0482-y
12/2019

Placental villous hypermaturation is associated with improved neonatal outcomes
Placenta
Julian K. Christians and David Grynspan
DOI: 10.1016/j.placenta.2019.01.012
01/2019

Pappa2 deletion has sex- and age-specific effects on bone in mice
Growth Hormone and IGF Research
DOI: 10.1016/j.ghir.2018.10.006
2019

PAPP-A2 deficiency does not exacerbate the phenotype of a mouse model of intrauterine growth restriction
Reproductive Biology and Endocrinology
Julian K. Christians and Kendra I. Lennie and Maria F. Huicochea Munoz and Nimrat Binning
DOI: 10.1186/s12958-018-0376-4
12/2018

The problem with using the birthweight:placental weight ratio as a measure of placental efficiency
Placenta
Julian K. Christians and David Grynspan and Susan L. Greenwood and Mark R. Dilworth
DOI: 10.1016/j.placenta.2018.06.311
08/2018

Associations between imprinted gene expression in the placenta, human fetal growth and preeclampsia
Biology Letters
Julian K. Christians and Katherine Leavey and Brian J. Cox
DOI: 10.1098/rsbl.2017.0643
11/2017

A maternal high-fat, high-sucrose diet has sex-specific effects on fetal glucocorticoids with little consequence for offspring metabolism and voluntary locomotor activity in mice
PLOS ONE
Eunice H. Chin and Kim L. Schmidt and Kaitlyn M. Martel and Chi Kin Wong and Jordan E. Hamden and William T. Gibson and Kiran K. Soma and Julian K. Christians
DOI: 10.1371/journal.pone.0174030
03/2017

An evaluation of Interprofessional group antenatal care: A prospective comparative study
BMC Pregnancy and Childbirth
DOI: 10.1186/s12884-017-1485-3
2017

Experimental reduction of haematocrit affects reproductive performance in European starlings
Functional Ecology
DOI: 10.1111/1365-2435.12511
2016

Haematocrit, eggshell colouration and sexual signaling in the European starling (Sturnus vulgaris)
BMC Ecology
DOI: 10.1186/s12898-016-0084-x
2016

ADAM12 and PAPP-A: Candidate regulators of trophoblast invasion and first trimester markers of healthy trophoblasts
Cell Adhesion and Migration
DOI: 10.1080/19336918.2015.1083668
2016

PAPP-A2 expression by osteoblasts is required for normal postnatal growth in mice
Growth Hormone and IGF Research
DOI: 10.1016/j.ghir.2015.09.003
2015

Pappa2 deletion in mice affects male but not female fertility
Reproductive Biology and Endocrinology
DOI: 10.1186/s12958-015-0108-y
2015

Pappa2 deletion alters IGFBPs but has little effect on glucose disposal or adiposity
Growth Hormone and IGF Research
DOI: 10.1016/j.ghir.2015.07.001
2015

When are sex-specific effects really sex-specific?
Journal of Developmental Origins of Health and Disease
DOI: 10.1017/S2040174415001348
2015

First-trimester levels of pregnancy-associated plasma protein A2 (PAPP-A2) in the maternal circulation are elevated in pregnancies that subsequently develop preeclampsia
Reproductive Sciences
DOI: 10.1177/1933719113512532
2014

IGFBP-4 and -5 are expressed in first-trimester villi and differentially regulate the migration of HTR-8/SVneo cells
Reproductive Biology and Endocrinology
DOI: 10.1186/1477-7827-12-123
2014

Pregnancy Associated Plasma Protein A2 (PAPP-A2) Affects Bone Size and Shape and Contributes to Natural Variation in Postnatal Growth in Mice
PLoS ONE
DOI: 10.1371/journal.pone.0056260
2013

Placental invasion, preeclampsia risk and adaptive molecular evolution at the origin of the great apes: Evidence from genome-wide analyses
Placenta
DOI: 10.1016/j.placenta.2012.12.001
2013

Quantitative trait locus (qtl) mapping reveals a role for unstudied genes in aspergillus virulence
PLoS ONE
DOI: 10.1371/journal.pone.0019325
2011

Virulence in an insect model differs between mating types in Aspergillus fumigatus
Medical Mycology
DOI: 10.3109/13693786.2010.512301
2011

A major QTL controls susceptibility to spinal curvature in the curveback guppy
BMC Genetics
DOI: 10.1186/1471-2156-12-16
2011

Regulation of pregnancy-associated plasma protein A2 (PAPPA2) in a human placental trophoblast cell line (BeWo)
Reproductive Biology and Endocrinology
DOI: 10.1186/1477-7827-9-48
2011

Altered levels of insulin-like growth factor binding protein proteases in preeclampsia and intrauterine growth restriction
Prenatal Diagnosis
DOI: 10.1002/pd.2583
2010

Altered placental expression of PAPPA2 does not affect birth weight in mice
Reproductive Biology and Endocrinology
DOI: 10.1186/1477-7827-8-90
2010

Expression of pregnancy-associated plasma protein A2 during pregnancy in human and mouse
Journal of Endocrinology
DOI: 10.1677/JOE-09-0136
2009

Mononucleotide repeats represent an important source of polymorphic microsatellite markers in Aspergillus nidulans
Molecular Ecology Resources
DOI: 10.1111/j.1755-0998.2008.02395.x
2009

Influence of sex steroid hormones on spatial memory in a songbird
Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
DOI: 10.1007/s00359-008-0369-4
2008

Fine mapping dissects pleiotropic growth quantitative trait locus into linked loci
Mammalian Genome
DOI: 10.1007/s00335-007-9018-4
2007

No evidence for inbreeding avoidance in a great reed warbler population
Behavioral Ecology
DOI: 10.1093/beheco/arl062
2007

PAPPA2, an enzyme that cleaves an insulin-like growth-factor-binding protein, is a candidate gene for a quantitative trait locus affecting body size in mice
Genetics
DOI: 10.1534/genetics.106.057513
2006

Regulatory variation at glypican-3 underlies a major growth QTL in mice.
PLoS biology.
2005

Regulatory variation at glypican-3 underlies a major growth QTL in mice
PLoS Biology
DOI: 10.1371/journal.pbio.0030135
2005

Behavioural genetics: Finding genes that cause complex trait variation
Current Biology
DOI: 10.1016/j.cub.2004.12.013
2005

Behavioural genetics
BioEssays
DOI: 10.1002/bies.20247
2005

Genetic complexity of an obesity QTL (Fob3) revealed by detailed genetic mapping
Mammalian Genome
DOI: 10.1007/s00335-004-3039-z
2004

Fine mapping of a murine growth locus to a 1.4-cM region and resolution of linked QTL
Mammalian Genome
DOI: 10.1007/s00335-004-3046-0
2004

Identification and reciprocal introgression of a QTL affecting body mass in mice
Genetics Selection Evolution
DOI: 10.1051/gse:2004018
2004

What causes the decrease in haematocrit during egg production?
Functional Ecology
DOI: 10.1111/j.0269-8463.2004.00829.x
2004

Experimental dissociation of the effects of diet, age and breeding experience on primary reproductive effort in zebra finches Taeniopygia guttata
Journal of Avian Biology
DOI: 10.1111/j.0908-8857.2003.03080.x
2003

Characterization of a QTL affecting skeletal size in mice
Mammalian Genome
DOI: 10.1007/s00335-002-3041-2
2003

Avian egg size: Variation within species and inflexibility within individuals
Biological Reviews of the Cambridge Philosophical Society
2002

Effects of porcine follicle-stimulating hormone on the reproductive performance of female zebra finches (Taeniopygia guttata)
General and Comparative Endocrinology
DOI: 10.1006/gcen.2001.7737
2002

Genetic architecture: Dissecting the genetic basis of phenotypic variation
Current Biology
DOI: 10.1016/S0960-9822(02)00911-9
2002

Intraspecific variation in reproductive physiology and egg quality in the European Starling Sturnus vulgaris
Journal of Avian Biology
2001

Follicular development and plasma yolk precursor dynamics through the laying cycle in the European starling (Sturnus vulgaris)
Physiological and Biochemical Zoology
DOI: 10.1086/320427
2001

Interindividual variation in yolk mass and the rate of growth of ovarian follicles in the zebra finch (Taeniopygia guttata)
Journal of Comparative Physiology - B Biochemical, Systemic, and Environmental Physiology
DOI: 10.1007/s003600100174
2001

Seasonal decline in clutch size in European starlings: A novel randomization test to distinguish between the timing and quality hypotheses
Journal of Animal Ecology
DOI: 10.1046/j.0021-8790.2001.00566.x
2001

Producing extra eggs does not deplete macronutrient reserves in European Starlings Sturnus vulgaris
Journal of Avian Biology
2000

Trade-offs between egg size and number in waterfowl: An interspecific test of the van Noordwijk and de Jong model
Functional Ecology
DOI: 10.1046/j.1365-2435.2000.00444.x
2000

Enhanced immune function does not depress reproductive output
Proceedings of the Royal Society B: Biological Sciences
1999

Effects of exogenous 17ß-estradiol on the reproductive physiology and reproductive performance of European starlings (Sturnus vulgaris)
Journal of Experimental Biology
1999

Organ mass dynamics in relation to yolk precursor production and egg formation in European starlings Sturnus vulgaris
Physiological and Biochemical Zoology
DOI: 10.1086/316683
1999

Controlling for body mass effects: Is part-whole correlation important?
Physiological and Biochemical Zoology
DOI: 10.1086/316661
1999