title: In vivo investigations of the effect of short- and long-term recombinant growth hormone treatment on DNA-methylation in humans.
abstract: Treatment with recombinant human growth hormone (rhGH) has been consistently reported to induce transcriptional changes in various human tissues including peripheral blood. For other hormones it has been shown that the induction of such transcriptional effects is conferred or at least accompanied by DNA-methylation changes. To analyse effects of short term rhGH treatment on the DNA-methylome we investigated a total of 24 patients at baseline and after 4-day rhGH stimulation. We performed array-based DNA-methylation profiling of paired peripheral blood mononuclear cell samples followed by targeted validation using bisulfite pyrosequencing. Unsupervised analysis of DNA-methylation in this short-term treated cohort revealed clustering according to individuals rather than treatment. Supervised analysis identified 239 CpGs as significantly differentially methylated between baseline and rhGH-stimulated samples (p<0.0001, unadjusted paired t-test), which nevertheless did not retain significance after adjustment for multiple testing. An individualized evaluation strategy led to the identification of 2350 CpG and 3 CpH sites showing methylation differences of at least 10% in more than 2 of the 24 analyzed sample pairs. To investigate the long term effects of rhGH treatment on the DNA-methylome, we analyzed peripheral blood cells from an independent cohort of 36 rhGH treated children born small for gestational age (SGA) as compared to 18 untreated controls. Median treatment interval was 33 months. In line with the groupwise comparison in the short-term treated cohort no differentially methylated targets reached the level of significance in the long-term treated cohort. We identified marked intra-individual responses of DNA-methylation to short-term rhGH treatment. These responses seem to be predominately associated with immunologic functions and show considerable inter-individual heterogeneity. The latter is likely the cause for the lack of a rhGH induced homogeneous DNA-methylation signature after short- and long-term treatment, which nevertheless is well in line with generally assumed safety of rhGH treatment.
authors.affiliation: Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Kolarova
authors.affiliation: Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Ole
authors.initials: O
authors.lastname: Ammerpohl
authors.affiliation: Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Gutwein
authors.affiliation: Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Maik
authors.initials: M
authors.lastname: Welzel
authors.affiliation: Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Inka
authors.initials: I
authors.lastname: Baus
authors.affiliation: Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Felix G
authors.initials: FG
authors.lastname: Riepe
authors.affiliation: Institute of Human Genetics, University Hospital Aachen, Aachen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Eggermann
authors.affiliation: Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Almuth
authors.initials: A
authors.lastname: Caliebe
authors.affiliation: Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Paul-Martin
authors.initials: PM
authors.lastname: Holterhus
authors.affiliation: Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Reiner
authors.initials: R
authors.lastname: Siebert
authors.affiliation: Institute of Human Genetics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Bens
mesh_terms: D000293:Adolescent; D002648:Child; D015331:Cohort Studies; D019175:DNA Methylation / Q000187:drug effects*; D005260:Female; D019382:Human Growth Hormone / Q000494:pharmacology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism; D008297:Male; D013997:Time Factors
chemical_list: D019382:Human Growth Hormone