Molecularly-defined lactose malabsorption, milk consumption and anthropometric differences in adult males

BACKGROUND

Lactose malabsorption (LM) may be associated with reduced skeletal calcium content. Diagnosis to date has been based on indirect methods, with a high false-negative rate. Identification of the LCT polymorphism led to development of a PCR-based test.

AIM

To evaluate the PCR-based test compared to a combination the hydrogen breath test and the lactose tolerance test, and investigate anthropometrical differences, changes in bone mineral density and oral calcium intake according to LCT polymorphism and milk-drinking habits.

METHODS

All participants (n = 278) underwent clinical examination, with measurement of height, weight and bone density (DXA), and were genotyped for LCT polymorphism (LCT CC or LCT TT: CC is associated with LM). A subgroup (n = 51) had a hydrogen breath test and a lactose tolerance test, in addition to genotyping.

RESULTS

Detection of LM by LCT polymorphism was highly significant (p = 0.001). The correlation between LCT genotype and self-reported milk-intolerance or dislike of milk with was slight, but the correlation with functional tests was highly significant. Non-milk-drinkers were lighter (-5 kg) and significantly shorter (-4 cm) than milk-drinkers (p = 0.07 and 0.04, respectively). Total calcium consumption was lower among non-milk-drinkers by about 18% (p = 0.03).

DISCUSSION

Genotyping is an economic, quick and convenient method for diagnosing lactose malabsorption, with results comparable to existing tests. Sufficient calcium consumption may be relevant to body growth, as milk-drinkers were taller. Negative calcium bone balance may be prevented when provision is made for adequate calcium intake.

Characterization of the Cytokine Pattern of Porcine Bone Marrow-Derived Cells Treated with 1alpha,25(OH)2D3

The biologically active form of vitamine D(3) [1alpha,25(OH)(2)D(3)] has recently been described not only to influence bone metabolism but also to exert immunomodulating activities, which may have an impact on bone formation/resorption as well. In this study, we analysed the effects of 1alpha,25(OH)(2)D(3) on the cytokine pattern of porcine bone marrow-derived cells from piglets aged 1-3 weeks. After culture for 1 week, the number of osteoclasts was determined, with tartrate-resistant acid phosphatase (TRAP)-positive, multinucleated cells being considered osteoclasts. Cultured bone marrow cell-derived mRNA was subjected to semiquantitative RT-PCR specific for a panel of porcine cytokines (IL-1alpha, IL-6, IL-8, IL-10, and TNF-alpha). In addition, an immunofluorescence analysis using anti-porcine mAbs specific for IL-1beta, IL-2, IL-4, IL-6, IL-12, TNF-alpha, and IFN-gamma was performed. In order to prove the existence of a porcine homologue of the receptor activator of NF-kappaB ligand (RANKL) bone marrow cell- as well as porcine white blood cell-derived mRNA was investigated by RT-PCR using primer pairs specific for murine RANKL. Cell culture supernatant was analysed for soluble RANKL by means of an ELISA designed for quantification of human RANKL. By means of RT-PCR, expression of IL-1alpha, IL-6, IL-8, IL-10 and TNF-alpha mRNA could be found in cells cultured with and without 1alpha,25(OH)(2)D(3). Immunofluorescence analysis revealed that IL-1, IL-6, and TNF-alpha were produced by both stromal cells and osteoclasts. Besides its known osteoclastogenic effects, 1alpha,25(OH)(2)D(3) tended to downregulate the respective cytokines, but significantly upregulated RANKL expression. The homology between the porcine RANKL-specific sequence and the corresponding human RANKL sequence was 79%. The data found support the idea that porcine bone marrow cell cultures may provide a suitable alternative to murine systems in human osteological research.

Porcine dermatitis and nephropathy syndrome (PDNS) is associated with a systemic cytokine expression profile indicative of proinflammation and a Th1 bias

Porcine dermatitis and nephropathy syndrome (PDNS) is broadly discussed as a porcine circovirus type 2 (PCV2)-associated disease, although PCV2, in contrast to postweaning multisystemic wasting syndrome (PMWS), has to date not been proven to be the aetiologic agent. In order to better understand the complex immunopathology of PDNS, the systemic cytokine expression profiles of (i) five pigs suffering from PDNS, (ii) five animals suffering from naturally acquired PMWS and (iii) five controls were investigated at mRNA and protein levels by means of multiplex real-time RT-PCR and flow cytometric intracellular cytokine detection, respectively. IL-1alpha, IL-6 and IFN-gamma mRNA expressions were found to be elevated in PDNS pigs. At the protein level, an increased capacity of peripheral blood mononuclear cells to produce IL-2, IL-4, IL-6, IL-12, TNF-alpha and IFN-gamma was evident. Hematological investigations revealed a hypochromic anemia while basophils and monocytes were relatively and neutrophils absolutely increased in PDNS pigs. PCV2 antibody levels did not differ significantly between PDNS and PMWS affected animals. Taken results together, the cytokine profile of the PDNS affected animals together with hematological data pointed towards a proinflammatory condition supporting a Th1 bias. Cytokine data of PMWS affected animals exhibited only minor non-significant differences when compared to controls, only IL-10 was significantly decreased at the mRNA level.

Serum levels of cathepsin K decrease with age in both women and men

Bone turnover increases with age. In a previous study, we reported on bone metabolism in young and elderly women and men. The aim of the present investigation was to evaluate potential age- and gender-related changes in cathepsin K, a cysteine protease that plays an important role in the degradation of the organic matrix of bone. Twenty-five healthy premenopausal women, 24 young healthy men, 26 elderly women, and 25 elderly men participated in the study. Elderly women and men had significantly lower cathepsin K levels than younger ones. In both men and women, serum levels of cathepsin K were negatively correlated with age. In men there was a statistically significant negative correlation between serum levels of cathepsin K and osteoprotegerin, which inhibits osteoclast differentiation and activation. No association was found between serum levels of cathepsin K and bone-specific alkaline phosphatase, osteocalcin, or 25-hydroxy vitamin D. Thus, the age-related increase in OPG, which markedly inhibits the expression of cathepsin K, may also reduce serum levels of cathepsin K. Despite the age-related increase in bone resorption, this study shows lower cathepsin K values in elderly women and men than in younger subjects. It might be speculated that a different enzyme could compensate for the decline in cathepsin K during old age.

Evaluation of the Suitability of Monoclonal Antibodies for Flow Cytometric Intracellular Cytokine Detection in Porcine Peripheral Blood Lymphocytes

Panels of monoclonal antibodies (mAbs) specific for porcine interleukin (IL)-2, IL-4, IL-6, IL-12, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha were evaluated for their applicability in flow cytometric intracellular cytokine detection. Peripheral blood mononuclear cells were short-time stimulated in the presence of brefeldin-A, ionomycin and phorbol-12-myristate-13-acetate, fixed and incubated with the respective mAbs as well as phycoerythrin-conjugated second-step antibodies. Suitability of mAbs was judged by use of statistical data and by visual control of scattergrams, considering the capability of mAbs to discriminate between cytokine-positive and cytokine-negative cell populations. The number of suitable clones differed to a high degree between the investigated cytokines, but at least one mAb fitting for flow cytometric intracellular cytokine detection could be identified within each panel. Monoclonal Abs producing scattergrams with a clear demarcation between positive and negative cell populations were found within the anti-IL-2, IL-6 and IFN-gamma panels, whereas less well defined positive and negative cell populations could be generated by use of mAbs within the anti-IL-4 and TNF-alpha panels. Only one moderately fitting mAb was identified within the anti-IL-12 panel. After having evaluated the best fitting mAbs, these were used to obtain reference levels for the physiological range of porcine lymphocytic cytokine production in a second set of experiments. For that reason, 13 clinically healthy pigs aged between 6 weeks and 6 months were investigated. Data presented are given as mean +/- SD of the percentage of positive-staining lymphocytes: IL-2, 45.5 +/- 27.6; IL-4, 34.1 +/- 21.3; IL-6, 45.4 +/- 23.8; IL-12, 13.9 +/- 8.6; TNF-alpha, 43.4 +/- 11.3; IFN-gamma, 65.5 +/- 14.8.

Leflunomide inhibits transendothelial migration of peripheral blood mononuclear cells

OBJECTIVES

To test whether the active metabolite of leflunomide (LEF-M), in addition to blocking the proliferation of activated lymphocytes by inhibiting dihydro-orotate dehydrogenase (DHODH), influences the transendothelial migration (TEM) of peripheral blood mononuclear cells (PBMC).

METHODS

In an in vitro model of PBMC transmigration through an endothelial cell (EC) barrier, PBMC were re-collected in three groups: cells not adherent to the EC, cells bound to, and cells which had migrated through, the EC layer. Experiments in which cells were pretreated with LEF-M (in the absence or in the presence of uridine) were compared with parallel experiments in the presence of medium alone.

RESULTS

Preincubation of EC with LEF-M led to a 36 (SEM 16)% reduction in PBMC TEM (p<0.05). Likewise, preincubation of PBMC induced a reduction in their TEM of 39 (9)% (p<0.005). Incubation of both PBMC and EC with LEF-M had an additive effect (mean reduction of 48 (6)%, p<0.005). Incubation of PBMC with LEF-M also decreased monocytic CD44 expression (p<0.005) and PBMC-hyaluronan binding (p<0.05). Incubation of cells with LEF-M and uridine in addition to LEF-M reversed the inhibition of migration, suggesting that the observed effects were due to DHODH inhibition. Fluorocytometric analysis of PBMC subsets within the migrated population showed a decrease of monocytes, but not of B or T cells, after LEF-M treatment.

CONCLUSIONS

LEF-M reduces monocytic adhesion molecule expression and TEM and may thus interfere with monocyte and EC activities in RA. Thus, the clinical effects of leflunomide may, at least in part, be due to blocking cell traffic into the inflamed synovia.

Bone metabolism in patients more than five years after bone marrow transplantation

We investigated the bone metabolism of 22 patients (median age 38 years) over 6 years after allogeneic bone marrow transplantation (BMT). Biplanar roentgenograms of the thoracic and lumbar spine were used to diagnose vertebral deformities caused by fractures. The actual bone mineral density (BMD) of the lumbar spine and the femoral neck were measured. Laboratory tests included calcium, phosphate, parathyroid hormone, a marker of bone resorption (beta-crosslaps, CTX), markers of bone formation (osteocalcin, bone-specific alkaline phosphatase), osteoprotegerin (OPG)--antagonist of the osteoclast differentiation factor RANKL, and sex hormone status. One patient had a vertebral fracture. Seven patients (28%) had osteopenia in the lumbar spine while 12 patients (48%) had osteopenia in the femoral neck. Bone resorption was increased in nine patients (43%) and bone formation was increased in four patients (20%). BMT recipients had significantly increased serum levels of OPG (P=0.029). Three women (75%) and four men (25%) were hypogonadal. The data showed that BMD is reduced and bone metabolism is still disturbed more than 6 years after BMT. The RANKL/osteoprotegerin system appears to play an important role in the pathophysiology of late post transplantation osteoporosis.

Systemic cytokine profile in feeder pigs suffering from natural postweaning multisystemic wasting syndrome (PMWS) as determined by semiquantitative RT–PCR and flow cytometric intracellular cytokine detection

Postweaning multisystemic wasting syndrome (PMWS) is an economically important disease in pigs caused by porcine circovirus type 2 (PCV2). Development of this disease is presumably associated with an impairment of the immune system. We, therefore, investigated the systemic expression of relevant cytokines (IL-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p40, TNF-alpha, IFN-gamma) and IL-2Ralpha at mRNA (semiquantitative RT-PCR) and at protein level (flow cytometric intracellular cytokine detection after short-time stimulation of peripheral blood mononuclear cells) in 10 feeder pigs aged 14 weeks suffering from natural PMWS and in 10 clinically healthy pen-mates. Hematological examination revealed a significant (p < 0.001) relative lymphopenia in the diseased animals when compared to reference pigs. IL-1alpha and IL-10 mRNA levels were notably increased in the affected pigs, whereas IL-2 and IL-2Ralpha (CD25) mRNA levels tended to be down-regulated. IL-8, TNF-alpha and IFN-gamma mRNA expressions appeared to be slightly increased. Intracellular cytokine levels as measured by flow cytometry revealed an increase of IL-1beta, IL-2, and IL-6, whereas IL-12 and TNF-alpha expressions were not affected. IFN-gamma was slightly decreased in the diseased animals. In conclusion, despite the assumption, that the cellular immune response to PMWS as a virus-induced disease should be characterized by either a Th1 driven cytokine profile or a cytokine profile indicative of T cell immunosuppression, our results did not support that hypothesis. Nevertheless, data from intracellular cytokine detection suggest an even increased percentage of the remaining lymphocytes capable to produce IL-2 upon in vitro stimulation, which is in contrast to the slightly diminished IL-2 mRNA levels reflecting the in vivo situation at least at the mRNA level.

Serum levels of osteoprotegerin increase with age in a healthy adult population

Regulation of the balance of osteoblastic and osteoclastic activity is critical for the understanding of normal cell biology and forms the basis of metabolic bone diseases. Our study reports about influences of age and gender on serum levels of osteoprotegerin (OPG) and its association to other clinical parameters of bone metabolism in a precisely determined cohort of 1134 healthy subjects at 17 Austrian outpatient bone clinics, aged between 19 and 96 years (females n = 687, 50 +/- 21 years, 19-94, and males n = 447, 52 +/- 13.5 years, 24-96). Mean OPG serum levels for all participants were 50.83 +/- 51.47 pg/ml (n = 1134; median 36, 2-584) and we observed a sharp increase in females after 60 years and in males after 70 years of age. OPG serum levels increased significantly by age, 2.1 pg/ml in females and 1.9 pg/ml in males for every year (P < 0.0001). Correlation of OPG serum levels and several bone parameters of bone metabolism showed that OPG negatively correlated with serum iPTH (r = -0.14; P < 0.001) and with serum estradiol in females (r = -0.16, P < 0.0001). Bone mineral density measured by DXA method at the spine and at the hip did not correlate with OPG serum levels, except a borderline negative correlation at the trochanteric region (r = -0.1, P < 0.05) in females only. Our results show a significant increase of osteoprotegerin with age in healthy females and males but fluctuations do not predict bone mineral density under in vivo conditions.

[Osteoporosis in premenopausal women]

Osteoporosis is a systemic disease of bone, which is characterized by decreased bone mass and changes in the microarchitecture of bone tissue followed by brittleness of bones and increased risk of fractures. Osteoporosis frequently is a disease of postmenopausal women, nevertheless, in rare cases, osteoporosis can also occur in young adults. There are only few studies on the pathophysiology of "premenopausal osteoporosis"; in addition to idiopathic forms, osteoporosis in young women can be caused by glucocorticoid treatment, by eating disorders or can be associated with pregnancy.

[Guidelines for drug therapy of postmenopausal osteoporosis]

Osteoporosis is known as a condition characterized by low bone mass and microarchitectural deterioration of bone tissue leading to bone fragility and a consequent susceptibility to fracture. Osteoporosis has its highest rate of occurrence in postmenopausal women, and in Western countries it has been estimated that for white women aged fifty, the life-time risk of developing an osteoporotic fracture is nearly 40%. Given the consequences of osteoporosis, the most important goal of therapy is to prevent fractures. In Austria, several pharmacologic options for treatment of osteoporosis are available, including bisphosphonates (alendronate, etidronate, risedronate), selective estrogen receptor modulators (raloxifene), calcitonins (salm-calcitonin, elcatonin), fluorides (sodium-fluoride, monofluorophosphate), anabolic steroids (nandrolone-decanoate), steroid derivates (tibolone), estrogen and hormone replacement therapy. An evidence-based evaluation of these treatment options clearly indicates that alendronate, risedronate and raloxifene sufficiently reduce the risk of vertebral fractures. There is less evidence for reduction of vertebral fracture risk for etidronate, calcitonin, estrogen replacement therapy or hormone replacement therapy. Only alendronate and risedronate have been shown to reduce the risk of hip fractures. Calcium and vitamin D are useful adjuncts to any specific treatment for osteoporosis, particularly when Calcium and vitamin D deficiencies have been diagnosed. Also, there is good evidence that in women with Calcium and vitamin D deficiency, a combination of Calcium and vitamin D may reduce the risk of non-vertebral fractures. There is no evidence so far that a combination therapy of antiresorptive drugs would result in reduced fracture risk.

[Pathogenesis of osteoporosis in rheumatoid arthritis]

Osteoporosis is a major clinical problem in rheumatoid arthritis. Patients with rheumatoid arthritis frequently not only present with juxta articular osteopenia and bone erosions but also with generalized axial and appendicular osteoporosis at sites distant from inflamed joints. The pathogenesis of bone loss in rheumatoid arthritis is multifactorial; disease activity certainly is a major determinant of bone mass. Further pathogenetic factors include effects of anti-inflammatory therapies (in particular glucocorticoids), reduced mobility, estrogen and/or androgen deficiency. Recently, receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG), a decoy receptor for receptor activator of nuclear factor kappa B ligand, were identified as central regulators of osteoclast recruitment and activation. Osteoprotegerin and receptor activator of nuclear factor kappa B ligand production is modulated by several cytokines, growth factors and hormones. In rheumatoid synovium both fibroblasts and activated T cells express receptor activator of nuclear factor kappa B ligand and thereby promote osteoclast recruitment and activation. Thus, osteoprotegerin and receptor activator of nuclear factor kappa B ligand appear to represent important molecular links between the immune system and bone metabolism in rheumatoid arthritis.

Quantitative ultrasound in the assessment of bone status of patients suffering from rheumatic diseases

OBJECTIVE

To explore the effects of rheumatic diseases and glucocorticoids on bone mass a group of patients suffering from systemic lupus erythematosus (SLE, n=18) and rheumatoid arthritis (RA, n=22) were examined.

DESIGN

We examined 40 patients and 48 controls with quantitative ultrasound (QUS) and dual-energy X-ray absorptiometry (DXA).

RESULTS

QUS (broadband ultrasound attenuation, BUA; speed of sound, SOS) values were found to be significantly lower in patients than in controls ( P<0.001). QUS measurements were moderately correlated with DXA measurements (kappa score ( kappa) 0.28 at the lumbar spine, and 0.46 at the femoral neck). There were no significant relations between the dosage of glucocorticoids and QUS parameters.

CONCLUSION

In patients suffering from inflammatory rheumatic diseases QUS values were significantly decreased. SOS but not BUA and DXA measurements reflected disease activity assessed by erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). QUS reflects different aspects of bone status compared with DXA.

[Osteoporosis in the man]

Osteoporosis in men is a severe condition probably more frequent than generally expected. The life-time risk of a low trauma fracture in a 60 year old man is 25%; moreover, approximately one third of hip fractures occurs in men. In contrast to postmenopausal osteoporosis, osteoporosis in men is frequently a secondary condition. In approximately 50% of cases, male osteoporosis is associated with an underlying disease or condition such as hypogonadism or long-term glucocorticoid treatment. Data from our group indicate that low serum estradiol levels and elevated sex hormone binding globulin levels may play a role in the pathogenesis of idiopathic male osteoporosis. Potential treatment modalities of osteoporosis in men include calcium and vitamin D supplementation, testosterone, fluoride, bisphophonates, calcitonin and parathyroid hormone. Currently, the data available favor the use of an aminobisphosphonate for the treatment of (idiopathic or glucocorticoid induced) osteoporosis.

[Sex differences in joint diseases: pathophysiological basis]

Gender affects the susceptibility to many joint diseases, in particular autoimmune rheumatic disorders; women have an increased risk of rheumatoid arthritis, systemic lupus erythematosus or Sjögren's syndrome. In rheumatoid arthritis alterations of sex hormone levels such as androgen deficiency or prolactin excess might, at least in part, explain the excess incidence in women. Osteoarthritis of the hand and the knee as well as generalized osteoarthritis is more frequent in women than in men. Nevertheless, until now there is no explanation for the increased incidence of osteoarthritis in women.

[Paget disease or fibrous dysplasia of the radius?--A case report]

A 46 years old man, who showed a painful and progressive deformity of the left radius, is presented. After some months a fracture within the affected bone area occurred. The diagnostic procedures including X-ray, MRI, scintigraphy and histology were controversial. Both fibrous dysplasia and Paget's disease of bone were suspected. The critical analysis of all results concluded that the most likely diagnosis was fibrous dysplasia. Unaware of the diagnostic discrepancies, the patient received a therapy with pamidronate 3 x 60 mg intravenously, which improved symptoms. After 14 months, the patient complained again about pain in the left radius. After a second therapy with pamidronate the patient currently exhibits no symptoms. The controversial diagnostic results and the applied therapeutic procedure are discussed.

Immune phenotype and intracellular cytokine production of peripheral blood mononuclear cells from postmenopausal patients with osteoporotic fractures

A number of factors with known effects on bone turnover are also immune regulatory factors. Disturbances of bone remodeling thus may be a consequence of altered local immune reactivity. We therefore determined surface markers and intracellular cytokine production of peripheral blood mononuclear cells by four-color flow cytometry in 19 postmenopausal patients with established osteoporosis and a control group of 11 postmenopausal women without fragility fractures. No significant differences in bone mineral density as assessed by dual energy X-ray absorptiometry were observed between the two groups. The following surface markers and cytokines were studied: CD3, CD4, CD8, CD16, CD19, CD29, CD45RA, CD56, CD57, HLA-DR, interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-13, tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma and granulocyte macrophage colony stimulating factor. In the fracture patients, the percentage of CD8+ cells co-expressing CD57 was increased (14+/-2 vs. 8+/-1%; p=0.03). Moreover, the proportion of CD8+ cells co-expressing TNF-alpha (47+/-5 vs. 33+/-4; p=0.05) and both TNF-alpha and IFN-gamma was significantly higher in the patients than the controls (41+/-6 vs. 22+/-3%; p=0.04). IL-1beta expression tended to be increased in monocytes from patients with established osteoporosis. Distinct subsets of CD8+ cells thus appear to contribute to the development of osteoporotic fractures.

Characterization of a vitamin D receptor knockout mouse as a model of colorectal hyperproliferation and DNA damage

The vitamin D receptor knockout (VDR-KO) mouse presents with a skeletal phenotype typical for complete lack of genomic 1,25-dihydroxycholecalciferol effects. Our previous data from human colorectal tissue suggest that the steroid hormone and its receptor may have protective function against tumour progression. In order to investigate the relevance of the vitamin D system for pre-malignant site-directed changes in the colon, we characterized the amount and site-specific distribution of the VDR along the large intestine in wild-type (WT), heterozygote (HT) and KO mice. We also evaluated expression of proliferating cell nuclear antigen (PCNA), of cyclin D1 and the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress. In colon ascendens, proliferative cells were dispersed all along the crypt and expression levels of all three markers were high in WT mice. A decrease of VDR expression did not affect expression significantly. In colon descendens, however, fewer proliferative cells were solely located in the lower third of the crypt, and an inverse relationship between VDR reduction, PCNA positivity and cyclin D1 expression was found in HT and KO mice. In parallel to enhanced proliferation a highly significant increase of 8-OHdG positivity occurred. Therefore, the sigmoid colon of VDR-KO mice, fed on an appropriate lactose/calcium-enriched diet to alleviate impaired calcium homeostasis-related phenotypic changes, is an excellent model for investigating induction and prevention of pre-malignant changes in one of the hotspots for human colorectal cancer incidence.

A comparison of quantitative computed tomography and dual X-ray absorptiometry for evaluation of bone mineral density in patients on chronic hemodialysis

Chronic renal failure leads to a reduction of bone mineral density (BMD). Therefore, noninvasive methods to evaluate BMD are also used regularly in this patient population. In this study, we compared the results of two widely used methods, quantitative computed tomography (QCT) of the lumbar spine and dual x-ray absorptiometry (DXA) at different sites in 90 patients on chronic hemodialysis. Additionally, we also determined various clinical and biochemical data to assess their relationship to BMD at the different measurement sites. A total of 75% of our patients was found to have reduced BMD, and 25% had an average z-score below -2. Z-scores obtained by the different methods and at the different measurement sites within an individual patient varied considerably from completely normal to severely reduced values. Multivariate analyses using clinical and biochemical parameters showed lower values of BMD at all measurement sites after transplantation and marginally higher values after parathyroidectomy, which was seen only in DXA measurement at the femoral neck. We conclude from our study that determination of BMD in chronic hemodialysis patients yields highly variable results, depending on the technique used. As long as the exact clinical relevance of these results has not been determined, regular routine measurement of isolated sites of BMD cannot be advocated in this patient population.

Bone turnover markers and sex hormones in men with idiopathic osteoporosis

BACKGROUND

In contrast to osteoporosis in postmenopausal women, osteoporosis in men has received much less attention.

PATIENTS AND METHODS

We determined various biochemical parameters of bone metabolism and sex hormones in 31 men with idiopathic osteoporosis and 35 age matched control subjects.

RESULTS

In the men with osteoporosis, a significantly increased urinary excretion of deoxypyridinoline (5.3 +/- 0.2 vs. 4.6 +/- 0.2 nmol mmol-1 creatinine; P = 0.033) in addition to increased serum levels of the c-terminal telopeptide of type I collagen (2677 +/- 230 vs. 2058 +/- 153 pmol; P = 0.037) were found. While parameters of bone formation were not significantly different in the patients and controls, serum bone sialoprotein levels were significantly decreased in the patients (3.7 +/- 0.8 vs. 12.4 +/- 4.0 ng mL-1; P = 0.021). Moreover, in men with idiopathic osteoporosis, lower levels of estradiol (91.3 +/- 5.8 vs. 114.6 +/- 7.8 pmol L-1; P = 0.044), higher levels of sex hormone binding globulin (31.5 +/- 3.1 vs. 24.2 +/- 1.4 nmol L-1; P = 0.034) and a decreased free androgen index (42.6 +/- 5.2 vs. 56.4 +/- 5.9; P = 0.016) were seen. Serum estradiol levels correlated negatively with several parameters of bone resorption.

CONCLUSIONS

In men with idiopathic osteoporosis, bone resorption is increased and exceeds bone formation. The excessive bone resorption seen in idiopathic male osteoporosis may be due to decreased estradiol levels and low levels of bioavailable testosterone.

Phenotypic characteristics of human monocytes undergoing transendothelial migration

In our study we characterised the immunophenotype of monocytes that migrated through an endothelial cell (EC) monolayer in vitro. We found that monocyte migration led to an enhanced expression of CD11a, CD33, CD45RO, CD54 [intercellular cell-adhesion molecule (ICAM)-1] and human leucocyte antigen-DR. The most striking increase was observed for ICAM-1 when ECs were activated with tumour necrosis factor-alpha and interleukin-1alpha. The results of our study indicate the following: (1) there is a characteristic immunophenotype on the surface of monocytes after transendothelial migration; (2) this phenotype seems to be induced by interactions between monocytes and ECs; and (3) this change is enhanced by the pretreatment of ECs with cytokines. Taken together, the results suggest that local cytokine production activating ECs is sufficient to enhance monocyte migration and that this, in turn, can induce changes consistent with an activated phenotype known to be interactive between antigen-presenting cells and T cells. These results have implications for our pathogenetic insights into rheumatoid arthritis.