Cathepsin S controls adipocytic and osteoblastic differentiation, bone turnover, and bone microarchitecture.

Cathepsin S is a cysteine protease that controls adipocyte differentiation and has been implicated in vascular and metabolic complications of obesity. Considering the inverse relation of osteoblasts and adipocytes and their mutual precursor cell, we hypothesized that cathepsin S may also affect osteoblast differentiation and bone remodeling. Thus, the fat and bone phenotypes of young (3 months old) and aged (12 or 18 months old) cathepsin S knock-out (KO) and wild-type (WT) mice were determined. Cathepsin S KO mice had a normal body weight at both ages investigated, even though the amount of subscapular and gonadal fat pads was reduced by 20%. Further, cathepsin S deficiency impaired adipocyte formation (-38%, p<0.001), which was accompanied by a lower expression of adipocyte-related genes and a reduction in serum leptin, IL-6 and CCL2 (p<0.001). Micro-CT analysis revealed an unchanged trabecular bone volume fraction and density, while tissue mineral density was significantly lower in cathepsin S KO mice at both ages. Aged KO mice further had a lower cortical bone mass (-2.3%, p<0.05). At the microarchitectural level, cathepsin S KO mice had thinner trabeculae (-8.3%), but a better connected trabecular network (+24%). Serum levels of the bone formation marker type 1 procollagen amino-terminal-propeptide and osteocalcin were both 2-3-fold higher in cathepsin S KO mice as was the mineralized surface. Consistently, osteogenic differentiation was increased 2-fold along with an increased expression of osteoblast-specific genes. Interestingly, serum levels of C-terminal telopeptide of type I collagen were also higher (+43%) in cathepsin S KO mice as were histological osteoclast parameters and ex vivo osteoclast differentiation. Thus, cathepsin S deficiency alters the balance between adipocyte and osteoblast differentiation, increases bone turnover, and changes bone microarchitecture. Therefore, bone and fat metabolisms should be monitored when using cathepsin S inhibitors clinically.

The bone marker plot: an innovative method to assess bone turnover in women.

BACKGROUND: Biochemical markers of bone turnover reflect the resorptive and reconstructive effects that act on the skeleton. Although elevated markers are commonly interpreted as a sign of an increased turnover rate, the balance between bone resorption and formation is mostly neglected. We introduce a graphic report combining both complementary processes. MATERIALS AND METHODS: Bone turnover markers were measured in 599 women (aged 25-74 years). To set up reference ranges, 269 from 599 women were selected because of having T-scores > -1 and inconspicuous basic laboratory data. Concentrations of resorption and formation markers were mathematically transformed to build up plots with four fields, symbolizing fast and slow resorption and fast and slow formation processes. The reference data of bone turnover were represented by a 95% confidence ellipse. For individual marker plots, we converted data of bone turnover markers from therapy follow-up profiles of patients in a similar manner. RESULTS: In pre-, peri- and postmenopausal women (n= 190, 39 +/- 6 years; n= 35, 51 +/- 6 years; n= 44, 55 +/- 5 years, respectively), the medians of the bone resorption marker CrossLaps and of the bone formation markers osteocalcin and aminoterminal propeptide of type I procollagen were 0.13/0.16/0.22 ng mL(-1), 21/21/25 ng mL(-1) and 36/35/45 ng mL(-1), respectively. In postmenopausal women, the marker plots revealed a shift towards accelerated bone resorption. A discrimination from osteopenic women (n= 138) failed. CONCLUSION: The proposed marker plot facilitates the intuitive perception of bone turnover in individual patients as well as in patient groups by a synopsis of the balance between bone formation and resorption with the rate of these processes.

Serum levels of receptor activator of nuclear factor kappaB ligand (RANKL) in healthy women and men.

BACKGROUND: Osteoporosis is one of the most common conditions associated with aging. It is based on an excess of bone resorption over bone formation, leading to an imbalance of bone turnover. The receptor activator of nuclear factor kappaB ligand (RANKL) is an important regulator of bone metabolism. OBJECTIVE: The aim of this investigation was to evaluate potential age- and gender-related changes in free RANKL and total RANKL (free RANKL+RANKL/osteoprotegerin complexes). METHODS: Two hundred and forty volunteers with a median age of 48 years were included in the study. Serum levels of free RANKL and total RANKL were evaluated. RESULTS: On average, men have a 1.77-fold higher free RANKL level and a 2.12-fold higher free/total RANKL ratio than women of the same age. On average, the RANKL levels decrease by approximately 13% every five years. CONCLUSION: This study showed that serum levels of free RANKL and total RANKL decrease with age, and also revealed some gender-related differences.

Calcium supply, bone mineral density and genetically defined lactose maldigestion in a cohort of elderly men.

OBJECTIVE: To examine a relationship of molecularly defined lactose malabsorption (LM; by LCT-polymorphism) to calcium supply, bone mineral density (BMD) and parameters of bone metabolism in an elderly male cohort. Furthermore, to reveal gender differences in BMD, calcium consumption rates and parameters of bone metabolism according to LCT polymorphism in an existing female cohort. SETTING AND SUBJECTS: A total of 239 men, aged 61+/-9 yr, were available from a former population based study cohort. All men were of Caucasian origin and came from the same region. Blood was sampled for genotyping of the LCT polymorphism and determination of markers of bone metabolism. All participants underwent physical examination, measurement of bone density and completed a standardized calcium questionnaire. Identical procedures had been carried out in a female cohort before (no. 350). RESULTS: Distribution of the LCT genotype in the study cohort was 27% CC (associated with LM; adult-type hypolactasia), 55% TC and 18% TT (lactase persistence). Amounts of total ingested calcium were similar among the three genotype groups. Amounts of consumed milk were generally low in men, LCT polymorphism did not influence rates of milk consumption for men preferred other sources of calcium. BMD, markers of bone metabolism and fracture rates did not differ. General anthropometric characteristics did not differ between the LCT groups either. CONCLUSIONS: Under conditions of low milk intake LCT polymorphism does not alter bone density, markers of bone metabolism and fractures in this cohort of elderly Caucasian men.

Receptor activator of nuclear factor kappaB ligand and osteoprotegerin in men with thyroid cancer.

BACKGROUND: Suppressive thyroid hormone therapy is generally a lifelong treatment for patients with differentiated thyroid cancer (DTC). However, long-standing thyrotropin (TSH) suppression is a risk factor for osteoporosis. Osteoprotegerin (OPG) and receptor activator of nuclear factor kappaB ligand (RANKL) are central regulators of bone turnover. The aim was to analyze the effects of a suppressive thyroid hormone therapy in males with DTC on the OPG/RANKL system and on bone metabolism. PATIENTS AND METHODS: The OPG and soluble RANKL (sRANKL) were determined in 40 men (mean age, 53.2 years) with DTC on suppressive thyroid hormone therapy (TSH; 0.053 +/- 0.037 mU L(-1), duration 5.7 +/- 4.4 years) and 120 healthy controls matched for age. The markers of bone metabolism were C-terminal telopeptide of type I collagen in serum (sCTx) and osteocalcin (OC). RESULTS: The control group had OPG values (mean +/- SD) of 1.9 +/- 1.0 pmol L(-1) and sRANKL values of 0.40 +/- 0.62 pmol L(-1). In patients with DTC, results for OPG were 3.03 +/- 1.04 pmol L(-1) (P < 0.05) and for sRANKL were 0.13 +/- 0.16 pmol L(-1) (P < 0.05). The control group presented values for sCTx of 2669 +/- 1132 pmol L(-1) and for OC of 17.89 +/- 6.5 ng mL(-1). Patients with DTC on suppressive thyroid hormone therapy had increased sCTx values of 3810 +/- 2020 pmol L(-1) (P = 0.03) but comparable OC values of 19.21 +/- 7.67 ng mL(-1) (NS). CONCLUSIONS: Suppressive thyroid hormone therapy in men with DTC increased bone degradation and induced significant changes in the OPG/RANKL system. These changes include, besides the risk of osteoporosis, possible negative effects on the vascular function and an increased risk of cardiovascular disease.

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.

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.

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.

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.

Assessment of vitamin D and calcium status in healthy adult Austrians.

BACKGROUND: Because there is reason to assume that also in Austria calcium and vitamin D malnutrition is wide-spread, we initiated a comprehensive study on calcium and vitamin D status in relation to bone health in a large group of the normal adult population. SUBJECTS AND METHODS: We assessed dietary calcium and vitamin D intake, serum concentrations of Ca2+, phosphate, alkaline phosphatase, 25(OH)D, 1,25(OH)2D, parathyroid hormone (PTH), follicle-stimulating hormone (FSH), sex hormones and bone mineral density (BMD) by double-energy X-ray absorptiometry at five different skeletal sites in 648 females and 400 males (age 21-76 years). RESULTS: Mean daily intake of vitamin D (101 IU, range 0.2-320) and calcium (569 mg, range 40-2170) was significantly less than the respective recommended dietary allowances. Two hundred and seventy-one (26%) individuals had hypovitaminosis D with serum 25(OH)D < 12 ng mL(-1), while serum Ca2+ was less than normal in 82 (7.8%) subjects. Multiple regression analysis revealed significant correlations between mean calcium intake and BMD in the femoral region in the men (r = 0.13, P < 0.05) though not in the women. No consistent data could be obtained for associations between BMD and vitamin D status, except for 25(OH)D and BMD at the spine in the men (r = 0.10, P < 0.05). 25(OH)D correlated negatively (P < 0.05) with age in the women (r = -0.11) and with PTH in the women (r = -0.11) and men (r = -0.16). Inversely, a significant (P < 0.001) age-related increase in PTH was observed in both sexes (men, r = 0.19; women, r = 0.14). CONCLUSIONS: Prevalence of hypovitaminosis D in adult Austrians is an imminent risk for development of secondary hyperparathyroidism with advancing age, and requires timely correction of nutritional deficits.

Normative data of bone mineral density in an unselected adult Austrian population.

BACKGROUND: There is increasing evidence that correct interpretation of bone mineral density (BMD) measurements by dual energy X-ray absorptiometry (DEXA) requires a population-specific reference range. We therefore collected data on age-related BMD in a random sample of the normal adult Austrian population to establish an appropriate normative database. METHODS: We measured BMD by DEXA at five different skeletal sites in 1089 subjects, i.e. 654 females and 435 males, aged between 21-76 years, who had been recruited by 17 centres across Austria. RESULTS: Age-related bone loss was observed until age 65 years with significant changes at the lumbar spine (r = -0.23), total hip (r = -0.07), trochanter (r = -0.10), femoral neck (r = -0.30) and Ward's triangle (r = -0.40) in the women but only at the femoral neck (r = -0.23) and at Ward's triangle (r = -0.40) in the men. When we calculated T scores from the BMD data of the young normal adult study population and used the T score set points according to the WHO classification of osteopenia and osteoporosis, we found that, depending on the skeletal site measured, 7.6-27.4% of the women and 16-41% of the men in our study group had low bone mass, whereas 0.6-2.7% of the female and 0.2-1.0% of the male study population were osteoporotic. However, osteoporosis was indicated in 4-9-fold more females and 5-15-fold more males when we based our estimates on the normative data provided by the manufacturers of the DEXA systems. CONCLUSION: Our data underscore the importance of using a population-specific reference range for DEXA measurements to avoid overdiagnosis of osteoporosis.

Suspect cell convolutes in the bone marrow of a patient with renal cell carcinoma unmasked as atypical convolutes of hairy cells.

We describe a patient who concomitantly presented with renal cell carcinoma (RCC) and hairy cell leukemia (HCL). Hairy cells formed atypical cell convolutes on bone marrow smears that might have been mistaken for tumor metastases.

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.

[Osteoporosis in the man]. / Die Osteoporose beim Mann.

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.

Gender differences in fracture risk and bone mineral density.

We have investigated gender-related differences of bone mineral density and fracture threshold in 136 males (age, 60.7+/-9.3 years) and 337 females (age, 59.7+/-7.8 years) without evidence of secondary osteoporosis. Women and men were examined for total amount of spine fractures and bone mineral density by quantitative computed tomography (QCT) of three non-fractured vertebral bodies L1-L5. Females with lumbar fractures (n=96) when compared with non-fracture women (n=241) were older and had lower bone density at their vertebral sites. Males with vertebral fractures (n=52) were older and had a significantly reduced bone mineral density of the spine when compared with healthy males (n=84). When we compared gender-related vertebral fracture rates, we observed a significantly higher prevalence of vertebral fractures in the male population. After matching males and females for age and bone mineral density to exclude an influence of either variable, we compared the prevalence of vertebral fracture risk in both sexes with logistic regression analysis. Data of estimated fracture risk, differed very significantly for sex and bone density at the vertebral site, indicating that men present fracture at a higher bone density level compared with females; in 10% of study population fractures occurred at a QCT level of 105 mg/cm(3) in women and 120 mg/cm(3) in men. The estimated odds ratio for sex of 3.1 (95% CI) means a three-fold increased risk for vertebral fractures compared to males at a given density level. These results underline that a decreased bone mineral density leads to the occurrence of spine fractures in females and males as well.

Surface markers and transendothelial migration of dendritic cells from elderly subjects.

Age-related changes of immune functions have been extensively investigated in both humans and animal models; nevertheless, the literature on potential alterations of dendritic cells, potent antigen presenting cells responsible for initiating immune responses, with aging is very scarce. We studied the immuno-phenotype of peripheral blood dendritic cells of elderly and young subjects by three-color flow cytometry. In addition, the capacity of transendothelial migration, an important step in inflammatory reactions, of peripheral blood dendritic cells of elderly subjects was investigated in an in vitro model. The expression of HLA-DR in the peripheral blood dendritic cells of the elderly subjects was significantly decreased when compared to the young control subjects. The expression of various other surface markers was similar in the young and elderly subjects. The ability of transendothelial migration of dendritic cells was found to be unimpaired in the elderly subjects. Both in the young and elderly subjects a significantly higher expression of CD29, CD86, HLA-DR, and HLA-DQ in the dendritic cells that had migrated through the endothelium in comparison to nonadherent, nonmigrating cells was found. In the migrating dendritic cells of the elderly subjects a significantly increased expression of CD11c was observed, whereas the expression of CD54 was significantly enhanced in the migrating dendritic cells of the young subjects only. In conclusion, our results demonstrate intact functions and a normal immunophenotype of dendritic cells derived from elderly subjects. Dendritic cells thus seem to be functional and therefore are not responsible for the well-known decline of T cell functions with aging.

Bone mineral density and biochemical parameters of bone metabolism in female patients with systemic lupus erythematosus.

OBJECTIVE: To evaluate bone mineral density and biochemical parameters of bone metabolism in ambulatory premenopausal female patients with systemic lupus erythematosus (SLE). METHODS: 30 women who fulfilled the ARA criteria for the classification of SLE were studied. Lumbar and femoral bone mineral density was determined by dual energy x ray absorptiometry. Various laboratory parameters including serum calcium, serum phosphorus, alkaline phosphatase, bone specific isoform of alkaline phophatase, propeptide of type 1 procollagen, deoxypyridinoline excretion, telopeptide of type 1 collagen, serum creatinine, osteocalcin, parathyroid hormone, 25-OH vitamin D, testosterone, progesterone, estradiol, follicle stimulating hormone and luteinotropic hormone were measured. RESULTS: According to the WHO criteria 39% of all patients with SLE studied had normal bone mineral density, 46% had osteopenia and 15% had osteoporosis at the lumbar spine; at the femoral neck 38.5% had normal bone mineral density, 38.5% had osteopenia and 23% suffered from osteoporosis. Significantly lower osteocalcin levels were found in SLE patients. All other bone resorption and formation markers measured were not statistically different, but higher serum albumin corrected calcium and lower phosphorus values were found in the SLE group. Of all sex hormones tested lower testosterone and higher follicle stimulating hormone concentrations were seen in patients with SLE. CONCLUSION: A high incidence was found of osteopenia and osteoporosis in premenopausal patients with SLE. Bone diminution in SLE seems to be attributable, at least in part, to decreased bone formation in SLE patients.

Immunology and aging.

Aging is accompanied by numerous functional and phenotypic changes in T cells, B cells and monocytes/macrophages; moreover, increases in autoimmunity, infections and occurrence of cancer have been reported in aged people. Healthy elderly persons, defined according to the criteria of the SENIEUR protocol, show various alterations in immunocompetent cells. Recent data have shown that the distribution of the subsets of peripheral blood, T-cell subtypes, is influenced by age. With increasing age, CD45RA(+) naive cells are replaced by CD45RA(-) memory CD4(+) T cells. In the CD8(+) T-cell subset, we found an increased proportion of cells co-expressing CD57. In monocytes also, some alterations of the immunophenotype, for example the expression of the adhesion molecule CD54, were observed. A relative deficit of transendothelial migration with aging was found in T cells, whereas this function was not impaired in monocytes. The immunophenotype and the function of dendritic cells do no t appear to be affected by aging. Due to their capacity to present antigens to T cells and to induce T-cell proliferation, dendritic cells may provide a useful tool for immunotherapy. In conclusion, investigations of immune functions in aging people reveal that there is an alteration of the immunophenotype of T cells and monocytes. Several functions of T-cell accompanying mechanisms, for example cytokine production and cell migration, are also affected by aging. In contrast, dendritic cells do not seem to be influenced by the aging process.

[Prevention and prophylaxis of osteoporosis: options and limitations]. / Prävention und Prophylaxe der Osteoporose: Möglichkeiten und Grenzen.

Osteoporosis is considered a systemic disease involving decreased bone mineral content and increased fracture risk. Therefore, for young people, adults and also the elderly, any measures have to taken which could prevent fractures. In this respect, clinically, femoral neck fractures are most important, however, in vertebral fractures a rise in morbidity and mortality can also be demonstrated. Radius fractures occurring in advanced age lead to increasing care being required and loss of independence. From today's point of view, it is tried to divide preventive measurements into primary and secondary steps, depending on whether healthy subjects or patients suffering from chronic diseases are affected. To evaluate the fracture risk, apart from anamnesis, bone density measurement and, in recent times, biomarker are suitable for the assessment of bone turnover. As primary prevention, basic lifestyle measures are recommended, in case of a concomitant relevant basic disease secondary prophylaxis is instituted to contain bone mineral loss. The following survey is to show the importance of prevention and of prophylaxis in osteoporosis both for healthy people and for patients with various accompanying diseases, and to list present possible preventive measures.