Biomedical subjects

Jens Bollerslev

Publications and source records attributed to Jens Bollerslev.

24 records · Page 2Linked to original sources

PubMed2003

Age-related changes in cortical bone content of insulin-like growth factor binding protein (IGFBP)-3, IGFBP-5, osteoprotegerin, and calcium in postmenopausal osteoporosis: a cross-sectional study.

Serum GH and IGF-I levels decline with increasing age, whereas osteoprotegerin (OPG) increases. IGFs as well as OPG are present in bone matrix and mediate the effects of many upstream hormones (e.g. estrogen). To evaluate whether changes in these proteins may to some extent explain the decrease in bone mass in postmenopausal or senile osteoporosis, we measured bone contents of IGF-I, IGF-II, IGF binding protein (IGFBP)-3, IGFBP-5, and OPG in combined extracts obtained after EDTA and guanidine hydrochloride extraction in 60 postmenopausal women aged 47-74 (mean, 63) yr with a previous distal forearm fracture and a hip or spine Z-score less than 0. We found age-related increases in IGFBP-3 (r = 0.35; P < 0.01), IGFBP-5 (r = 0.59; P < 0.001), and OPG (r = 0.36; P < 0.01) in cortical bone, significantly inversely correlated with femoral neck and lumbar spine BMD. A correlation between age and OPG was also detected in trabecular bone (r = 0.27; P < 0.05). A pronounced age-related decrease in cortical calcium contents (r = -0.60; P < 0.001), positively correlated with femoral neck and lumbar spine BMD, was also found. No age-related changes were detected for IGF-I or IGF-II. The present study demonstrates age-related changes in cortical bone contents of IGFBPs, calcium, and OPG, possibly related to the pathophysiology of postmenopausal osteoporosis. As for OPG, our findings probably represent compensatory responses to increased osteoclastic resorption.

Age Factors↗

PubMed2003

Serum levels of TGF-beta and fibronectin in autosomal dominant osteopetrosis in relation to underlying mutations and well-described murine counterparts.

The study gives a further biochemical description of two different forms of autosomal dominant osteopetrosis (ADO) in relation to murine counterparts, with special attention to osteoblast function and the recent discovery of LRP5 gene mutations in ADO I. Patients and controls were investigated for markers of bone formation and resorption at baseline and following stimulation with thyroid hormone. Moreover, four different well-described murine models of osteopetrosis were investigated. Concerning the human forms, serum TSH levels decreased in all subjects, indicating effects on the target tissue. Osteocalcin and cross-linked collagen (NTx) were without significant differences among the groups. Significant increases in both markers were seen following stimulation. Baseline active TGF-beta1 levels were increased in both types of ADO (60% in ADO I [P = 0.006]; 46% in ADO II [P = 0.001], respectively), whereas fibronectin levels were decreased in both (ADO I 58% and ADO II 63% of normal, respectively [P = 0.012 and P = 0.001]). Following treatment, levels increased temporarily in all groups. In the murine models, active TGF-beta1 was significantly decreased in the tl- and ia-rat, whereas fibronectin levels were decreased in the mi-mouse, however, increased in the ia-rat. In conclusion, both types of ADO showed the same qualitative biochemical differences compared to controls, except that OPG levels were higher in ADO I. The decreased fibronectin levels in both types and in murine models reflect decreased bone resorption; however, this may also indicate hitherto unrecognized alterations in bone formation. Biochemical differences among known syndromes related to mutations in the LRP5 gene indicate different underlying pathogenetic mechanisms.

Adult↗

PubMed2002

[Osteoclast function is regulated by neighbouring osteoblasts. Osteoprotegerin, RAND and RANK ligand constitute a unique regulatory system for bone resorption with important pathophysiological and therapeutic aspects].

Maturation of macrophages to osteoclasts requires the presence of marrow stromal cells or osteoblasts. Most calcitropic hormones act indirectly on osteoclasts through receptors on neighbouring osteoblasts. The discovery of osteoprotegerin (OPG), the receptor activator of nuclear factor-kappa b ligand (RANKL), and its receptor (RANK) has elucidated these phenomena. It appears that osteoclast differentiation, activity, and survival are regulated by the proportion of inhibiting OPG to stimulating RANKL. OPG and RANKL are produced by osteoblasts, whereas RANK is located to the osteoclasts. Treatment with OPG inhibits bone resorption in postmenopausal women. Mutations in the system may be responsible for focal skeletal disorders. The discovery opens up for new treatment opportunities in postmenopausal and steroid-induced osteoporosis, Paget's disease, hypercalcaemia, and rheumatoid arthritis.

Bone Remodeling↗

PubMed2002

[Hyperprolactinemia and prolactinemia--investigation and treatment].

BACKGROUND: Prolactinoma represents the most commonly occurring hormone-secreting pituitary adenoma. The majority of prolactinomas are small, only rarely do we find larger prolactinomas, so-called macroadenomas. They are almost exclusively benign. The symptoms are mainly caused by elevated prolactin levels and result in changes to the reproductive and sexual function. In cases of macroprolactinomas, symptoms caused by local mass effects can be seen. A variety of other conditions may also cause hyperprolactinaemia; the goal of the examination is to identify the cause. MATERIAL AND METHODS: We have reviewed recent literature and compared findings with current management of hyperprolactinaemia and prolactinoma in Norwegian university hospitals. RESULTS AND INTERPRETATION: The primary treatment is medical, intended to normalize prolactin levels, restore gonadal function, and reduce tumour size. With the new selective dopamine agonists, the treatment is often simple and efficient, but not all patients are in need of treatment.

Adenoma↗

PubMed2002

Localization of the gene causing autosomal dominant osteopetrosis type I to chromosome 11q12-13.

The osteopetroses are a heterogeneous group of genetic conditions characterized by increased bone density due to impaired bone resorption by osteoclasts. Within the autosomal dominant form of osteopetrosis, the radiological type I (ADOI) is characterized by a generalized osteosclerosis, most pronounced at the cranial vault. The patients are often asymptomatic but some suffer from pain and hearing loss. ADOI is the only type of osteopetrosis not associated with an increased fracture rate. Linkage analysis in two families with ADOI from Danish origin enabled us to assign the disease-causing gene to chromosome 11q12-13. A summated maximum lod score of +6.54 was obtained with marker D11S1889 and key recombinants allowed delineation of a candidate region of 6.6 cM between markers D11S1765 and D11S4113. Previously, genes causing other conditions with abnormal bone density have been identified from this chromosomal region. The TCIRG1 gene was shown to underly autosomal recessive osteopetrosis (ARO), and, recently, mutations in the LRP5 gene were found both in the osteoporosis-pseudoglioma syndrome and the high bone mass trait. Because both genes map within the candidate region for ADOI, it can not be excluded that ADOI is caused by mutations in either the TCIRG1 or the LRP5 gene.

Adult↗

PubMed2002

Raised serum levels of interleukin-8 and interleukin-18 in relation to bone metabolism in endogenous Cushing's syndrome.

OBJECTIVE: It is well known that patients with endogenous Cushing's syndrome (CS) have decreased bone mass and enhanced risk for osteoporotic fractures, secondary to decreased bone formation and increased bone resorption. Immunological mediators, such as cytokines, have recently been shown to influence bone metabolism, and in the present study we examined serum levels of several cytokines, with known or potential effects on bone homeostasis, in 33 consecutive recruited untreated CS patients and 33 age-, sex- and body mass index-matched healthy controls. METHODS: Cytokine levels were measured by enzyme immunoassay and bone mass by dual-energy X-ray absorptiometry. RESULTS: Our main findings were (i) interleukin (IL)-8 and IL-18 levels were significantly increased in CS patients compared with controls. (ii) Levels of both IL-8 and IL-18 were positively correlated to serum cortisol. (iii) For serum levels of the 'classical' resorptive cytokines, i.e. IL-6 and tumor necrosis factor alpha, no significant differences were found between CS patients and controls. (iv) Raised IL-18 levels were correlated with decreased osteocalcin levels in CS patients. CONCLUSIONS: Our results demonstrated that CS patients have markedly elevated levels of the proinflammatory cytokines IL-8 and IL-18 in spite of high levels of the immunosuppressive hormone cortisol. These cytokines may be involved in the pathogenesis of disturbed bone homeostasis in CS.

Adult↗