Relation between sex hormones and leucocyte telomere length in men with idiopathic pulmonary fibrosis

Background and objective IPF is an ageing-related lung disorder featuring progressive lung scarring. IPF patients are frequently identified with short telomeres but coding mutations in telomerase can only explain a minority of cases. Sex hormones regulate telomerase activity in vitro and levels of sex hormones are related to LTL. The objective of this study was to explore whether sex hormones were associated with LTL, whether they interacted with genetic variants in telomerase and whether polymorphisms in the exon of androgen metabolism genes were associated with plasma testosterone concentrations in male IPF patients. Methods A case-control study was performed on 101 male IPF subjects and 51 age-matched healthy controls. Early morning plasma sex hormones were quantified, and whole-exome sequencing was used to identify rare protein-altering variants of telomerase and SNP in the exon of androgen metabolism genes. LTL was analysed by PCR and expressed as a T/S ratio. Results LTL, testosterone and DHT were decreased significantly in the IPF group. After adjustments for age and variant status in telomerase-related genes, only testosterone was positively associated with LTL (P= 0.001). No significant interaction (P= 0.661) was observed between rare protein-altering variants of telomerase and testosterone. No coding SNP in androgen metabolism genes were significantly associated with testosterone concentrations. Conclusion Plasma testosterone is associated with LTL independent of age or rare protein-altering variants of telomerase. No genetic variations of androgen-related pathway genes are associated with androgen concentrations. Further studies are warranted to examine whether hormonal interventions might retard telomere loss in male IPF patients.