Onderzoeksproject 1: Determinants of sex steroid status in relation to body composition and aging
The section of Endocrinology has a long track record of pioneering research in the area of physiopathology of sex steroids, with in particular research projects on the study of the determinants, the physiopathology and the consequences of altered sex steroid status in men.
Specifically, genetic variations and variations in glycosilation pattern of LH and SHBG (collaboration with the departments of Clinical Chemistry, Agricultural and Applied Biological Sciences and Dpt. of Molecular Biomedical Research VIB-Ghent University) are investigated in relation to sex steroid concentrations, body composition, aging and thyroid disorders. Studies are also pursued on the regulation of gonadotropin feedback regulation by sex steroids in young, elderly and obese men.
Onderzoeksproject 2: Genetics, and their interaction in the regulation of bone metabolism in men
A clinical investigation program by the Unit for Osteoporosis and Metabolic Bone Diseases (sections of Endocrinology and Rheumatology), the section of Endocrinology and the laboratory for Hormonology focuses on the study of the determinants of skeletal status in men, with particular attention for the interrelations between genetics, hormonal status, body composition and indices of muscle force. Recent/ongoing studies include:
- a population-based, prospective 4-year observational study in healthy men over 70 years of age in a semi-rural community (Merelbeke) on the determinants of sex steroid status and bone metabolism in elderly men, including the role of polymorphisms in candidate genes for regulation of sex steroid status and/or bone metabolism;
- a genetic study of osteoporosis in men using a family-based approach in men with idiopathic osteoporosis and their relatives: detailed phenoptyping and longitudinal follow-up; association studies; genome-wide screening; longitudinal study of bone acquisition in relatives during growth (collaboration with INSERM/Hôpital Lariboisière Paris, Prof. M.C. de Vernejoul, dpt Medical Genetics UGent and section of Pediatric Endocrinology UZGent);
- a study of the genetic determinants of sex steroid status and bone mass/metabolism in healthy young adult men using a sib-pairs approach; population based recruitment of up to 500 pairs of brothers: association studies for candidate genes; preparation of a genome-wide screening.
- studies of hormonal factors in secondary causes of osteoporosis in men: glucocorticoid-induced; hypogonadism; posttransplantation osteoporosis; growth hormone deficiency.
Onderzoeksproject 3: Effects of thyroid hormone status in relation to bone mass, body composition, metabolic factors and atherosclerosis
A novel research line has been initiated, investigating the relationship between thyroid hormone status, body composition, bone mass and early markers of atherosclerosis.
The genetic and environmental determinants of thyroid hormone status will be investigated at the level of the hypothalamus, pituitary gland, thyroid gland and target organs.
In young men, the relationship between circulating thyroid hormones, body composition and bone mass will be investigated in relation to genetic variants influencing thyroid hormone status.
In middle aged men and women, the effects of thyroid hormone status and genetic variation in the thyroid hormone pathways will be investigated in relation to early markers of atherosclerosis (Collaboration with the dpts of Cardiology and Epidemiology in the frame of the ASCLEPIOS Study)
Onderzoeksproject 4: Sex steroid status and intra-adipose sex steroid metabolism in relation to markers of vascular and cardia function, obesity and isulin sensitivity.
- Ongoing and planned studies pertain to the relationship between sex steroid status, body composition in relation to cardiovascular risk factors, vascular and cardiac function. The role of androgen receptor polymorphism, androgen sensitivity and aromatase polymorphism are investigated in the ASCLEPIOS-study. (collaboration with the Dpt of Cardiology & the Dept of Public Health)
- Intra-adipose sex steroid metabolism and expression of key molecular markers of fat metabolism in relation to insulin sensitivity are being investigated in a population of morbid obese subjects prior to and after gastric bypass surgery (collaboration Prof. P. Pattyn and Prof. Y. Van Nieuwenhove dept Gastro-intestinal surgery).
- The effects of aromatase-inhibition on insulin sensitivity (Clamp-studies) and intra-adipose expression of selected signalling molecules in fat and glucose metabolism are being investigated in a population of healthy males.
Onderzoeksproject 5: Clinical studies in adrology and related hormonal studies
- effects of hormonal treatments in transsexualism:
ongoing studies on sexual interest, on the different effects of hormonal treatment, on bone metabolism and long-term follow-up studies of the outcome of cross-gender hormonal treatments in transsexuals (in collaboration with the other members of the Gender Team of the Ghent University Hospital).
- role of genetic polymorphisms and environment on male (hormonal and semen) reproductive parameters.
- hormonal determinants of risk taking behaviour (collaboration dept of Sociology) and of sexual behaviour (collaboration dept of Sexology).
- Primary treatment of Cushing syndrome and acromegaly with long acting somatostatin analogues.
- Hormonal aspects of sexual health in Flanders: part of SEXPERT an interdisciplinary large scale investigation on sexual health in Flanders (collaboration of the Gender Team of the Ghent University Hospital, the dpts of Psychology and sociology at UGent, the dpt of Sexology KUL and SENSOA vzw),
Taes Y, Lapauw B, Vanbillemont G, Bogaert V, De Bacquer D, Goemaere S, Zmerczak H, Kaufman JM. Early smoking is associated with peak bone mass and prevalent fractures in young healthy men. J Bone Miner Res, 2009.
Lapauw B, Taes Y, Goemaere S, Toye K, Zmierczak HG, Kaufman JM. Anthropometric and skeletal phenotype in men with idiopathic osteoporosis and theirs sons is consistent with deficient estrogen action during maturation. J Clin Endocrinol Metab, 2009; 94:4300-4308.
Taes YE, Lapauw B, Vanbillemont G, Bogaert V, De Bacquer D, Zmierczak H, Goemaere S, Kaufman JM. Fat mass is negatively associated with cortical bone size in young healthy male siblings; J Clin Endocrinol Metab, 2009; 94:2325-2331.
BOGAERT V, VAN BILLEMONT G, TAES Y, DE BACQUER D, DE SCHEPPER E, VAN STEEN K, KAUFMAN JM. Small effect of the androgen receptor gene GGN repeat polymorphism on serum testosterone levels in healthy men. Eur J Endocrinol, 2009; 16:171-177.
Lapauw B, T’sjoen G, Mahmoud A, Kaufman JM, Ruige JB. Short-term aromatase inhibition : effects on glucose metabolism and serum leptin levels in young and elderly men. Eur J Endocrinol, 2009; 160(3):397-402.
Lapauw B, Goemaere S, Zmierczak H, Van Pottelbergh I, Mahmoud A, Taes Y, De Bacquer D, Vansteelandt S, Kaufman JM. The decline of serum testosterone levels in community-dwelling men over 70 years of age: descriptive data and predictors of longitudinal changes. Eur J Endocrinol, 2008; 159:459-468.
Elaut E, De Cuypere G, De Sutter P, Gijs L, Van Trotsenburg M, Heylens G, Kaufman JM, Rugens R, T’sjoen G. Hypoactive sexual desire in transsexual women : prevalence and association with testosterone levels. European Journal of Endocrinology, 2008; 158:393-399.