Significance of CA 27.29 (MUC 1 glycoprotein) levels in patients with breast cancer

e11579

Background: ASCO guidelines do not support the use of CA 15–3 and CA 27.29 for monitoring patients for recurrence after primary breast cancer therapy. However, several well-designed studies have shown that an increase in CA 15–3 or CA 27.29 after primary and/or adjuvant therapy can predict recurrence an average of 5 to 6 months before other symptoms or tests. We wanted to assess the significance of measuring the tumor marker (CA 27.29 levels) to monitor the clinical progress of breast cancer. Methods: After IRB approval, we conducted a retrospective chart review of 392 patients with breast cancer who had regular monitoring of CA 27.29 levels following the diagnosis of breast cancer. A total of 2671 values of CA 27.29 were evaluated from our institution over the past 5 years (2003–2008). Patient CA 27.29 levels were correlated with clinical progression of the disease (diagnostic imaging and history and physical examinations). Results: Out of 330 patients with Stage I, II, and III after treatment with adjuvant therapy, 316 had no evidence of disease (NED) and had normal levels(<38) of CA 27.29. Out of the14 patients with clinical evidence of disease recurrence, 3 had persistently elevated levels. Of the 62 patients with stage IV breast cancer following cheomotherapy, 29 patients had clinical progression of disease with 20 (69%) patients showing increasing levels. Out of the 33 patients with no evidence of progression of disease only 4(12%) had increasing levels. Conclusions: Our trend analysis concludes that a normal CA 27.29 level in patients with Stage I, II, and III, after adjuvant treatment, correlates well with clinically NED status and might be of reassuring benefit to the patients. However, increasing levels of CA27.29 in metastatic disease correlate well with clinical progression of the disease. A large multicenter prospective study is warranted to further assess the role of CA 27.29 for disease monitoring in locally advanced and metastatic breast cancer.

No significant financial relationships to disclose.

Baseline serum NTx levels are prognostic in metastatic breast cancer patients with bone-only metastasis

BACKGROUND

There is significant heterogeneity in survival of patients with metastatic breast cancer who have bone-only metastasis. We studied the correlation of serum N-telopeptide (NTx), a marker of bone resorption, and its correlation with clinical outcomes in patients with metastatic breast cancer with bone-only or bone plus soft tissue metastasis.

PATIENTS AND METHODS

Serum was taken from 250 metastatic breast cancer patients with bone-only or bone plus soft tissue metastasis who participated in two similar randomized studies of second-line hormone therapy. An enzyme-linked immunosorbent assay specific for NTx of type I bone collagen was used to detect serum levels.

RESULTS

Sixty patients (24%) had elevated serum NTx levels, using the mean + 2 standard deviations (26 nanomoles Bone Collagen Equivalents per liter) of healthy women as a cut-off. The median duration of clinical benefit was significantly shorter in the group with elevated serum NTx levels compared with the group that had normal serum NTx levels (P=0.0004). Time to progression (TTP) was also significantly shorter in the patients with elevated serum NTx at 139 days compared with 220 days (P=0.0006). Median survival was also significantly shorter in patients with elevated baseline serum NTx levels at 663 days compared with 941 days (P<0.0001).

CONCLUSION

In this study, breast cancer patients with bone-only or bone plus soft tissue metastasis and elevated serum NTx levels have a shorter duration of clinical benefit, TTP and overall survival.

Acute Effects of Moderate Intensity Resistance Exercise on Bone Cell Activity

Resistance exercise has positive effects on bone mass, but little is known about the mechanisms by which this occurs. The purpose of this study was to determine if a single bout of moderate intensity resistance exercise alters biochemical markers of bone cell activity. Indices of bone turnover were measured in nine healthy, untrained men (21.9 +/- 1.2 yrs old), before and following a single 45 minute session of resistance exercise, and during a control trial. A cross-over design was used so that all participants performed both trials in random order. Blood samples were collected immediately before, immediately after, and at 1, 8, 24, and 48 hours post exercise and analyzed for bone-specific alkaline phosphatase (BAP), type I collagen propeptide (PICP), and type I collagen N-telopeptide (sNTX). Urine from the second morning void was collected over four days (day before, day of, and two days following exercise) and analyzed for type I collagen N-telopeptide (uNTX). Exercise resulted in a significant increase (p < 0.05) in the ratio of biochemical markers of bone formation to bone resorption eight hours post exercise, largely due to a decrease in sNTX. Markers return to baseline within 24 hrs. These data suggest that moderate intensity resistance training acutely reduces bone resorption, leading to a favorable change in overall bone turnover, for at least 8 hours post exercise in untrained young men. Further work is needed to determine if long-term benefits to bone strength follow with persistent training.

Orthogonal assembly of nanoparticle building blocks on dip-pen nanolithographically generated templates of DNA

Nanoscale construction work with DNA: Dip-pen nanolithography (DPN) is used to generate nanostructures which can be subsequently functionalized with oligonucleotides a' and b' and used to assemble, in an orthogonal manner, gold nanoparticles (a, b in scheme) functionalized with sequences complementary to the DPN-generated structures.

Combinatorial templates generated by dip-pen nanolithography for the formation of two-dimensional particle arrays

Lattices of single polystyrene particles were constructed by using a combinatorial approach to analyze particle pattern recognition properties. Dip-pen nanolithography was used to generate chemical templates of 16-thiohexadecanoic acid on a gold surface to study the two-dimensional assembly of amine- and amidine-modified particles.

Direct patterning of modified oligonucleotides on metals and insulators by dip-pen nanolithography

The use of direct-write dip-pen nanolithography (DPN) to generate covalently anchored, nanoscale patterns of oligonucleotides on both metallic and insulating substrates is described. Modification of DNA with hexanethiol groups allowed patterning on gold, and oligonucleotides bearing 5'-terminal acrylamide groups could be patterned on derivatized silica. Feature sizes ranging from many micrometers to less than 100 nanometers were achieved, and the resulting patterns exhibited the sequence-specific binding properties of the DNA from which they were composed. The patterns can be used to direct the assembly of individual oligonucleotide-modified particles on a surface, and the deposition of multiple DNA sequences in a single array is demonstrated.

The potential role of estrogen in aromatase regulation in the breast

Aromatase is expressed in both normal and malignant breast tissues. Aromatase activity in the breast varies over a wide range. Our previous studies have demonstrated that in situ aromatization contributes to the estrogen content of breast tumors to a major extent. Consequently, alterations of aromatase activity could serve as a major determinant of tissue estradiol content. However, the mechanisms and extent of aromatase regulation in breast tissues have not been fully established. We have observed an inverse correlation between tumor aromatase activity and estrogen content in nude mice bearing xenografts of MCF-7 cells transfected with the aromatase gene. To investigate the potential role of estrogen in aromatase regulation in the breast, studies were carried out in an in vitro model. In this model, MCF-7 cells were cultured long term in estrogen-deprived medium and called by the acronym, LTED cells. We found that long-term estrogen deprivation enhanced aromatase activity by 3-4-fold when compared to the wild-type MCF-7 cells. Re-exposure of LTED cells to estrogen reduced aromatase activity to the levels of the wild-type MCF-7 cells. We also measured aromatase activity in 101 frozen breast carcinoma specimens and compared tumor aromatase activities in pre-menopausal patients versus post-menopausal patients and in post-menopausal patients with or without hormone replacement therapy (HRT). Although statistically not significant, there was a trend paralleling that observed in the in vitro studies. Aromatase activity was higher in breast cancer tissues from the patients with lower circulating estrogen levels. Our data suggest that estrogen may be involved in the regulation of aromatase activity in breast tissues.

The role of sex hormone replacement therapy on self-perceived competence in adolescents with delayed puberty

The objective of the present study was to determine the role of sex steroids in the development of self-perceived competence during adolescence. The Harter Self-Perception Scale was administered to 56 adolescents with delayed puberty who were receiving depo-testosterone (males) or conjugated estrogens (females) administered in 3-month blocks alternating with placebo. Treatment was given at three dose levels approximating early, middle, and late pubertal replacement levels. Hormone treatments had a significant positive effect for both males and females in one subscale domain--perceived job competence. Significant positive hormone effects were also obtained for perceptions of romantic appeal and close friendship in females and perception of athletic abilities in males. It can be inferred from the results of this study that the hormonal changes associated with sexual maturation have targeted influences on specific domains of self-perceived competence and that there are clear gender differences.

Bioavailable testosterone as a correlate of cognition, psychological status, quality of life, and sexual function in aging males: implications for testosterone replacement therapy

Andropause is a syndrome described in aging males, is composed of a constellation of physical, sexual, and emotional symptoms, and is thought to be related to declining concentrations of serum testosterone. Numerous studies of testosterone replacement therapy in elderly hypogonadal males have documented the physical benefits of such treatment, but have failed to assess cognition, psychological functioning, and quality of life. Male outpatients greater or equal to 55 years of age completed cognitive, psychological, sexual, and quality of life assessments. A serum sample was provided for bioavailable testosterone assay. The associations between bioavailable testosterone concentrations and neuropsychological testing were assessed using Spearman rank correlation. Overall, bioavailable testosterone was not an important determinant of cognitive, psychological, or sexual functioning or of quality of life. The implications for future studies involving testosterone replacement therapy are discussed.

Bone markers in the management of metastatic bone disease

Newer markers of bone formation and bone resorption are now available. Alone these new markers do not appear to be useful to diagnose metastatic bone disease. Several markers appear to be of prognostic importance and correlate with the extent of tumour in the skeleton. Serial monitoring of bone markers may be useful to monitor the efficacy of bisphosphonate and/or systemic therapy of both lytic and blastic bone metastases.

A fluorescence-based method for determining the surface coverage and hybridization efficiency of thiol-capped oligonucleotides bound to gold thin films and nanoparticles

Using a fluorescence-based method, we have determined the number of thiol-derivatized single-stranded oligonucleotides bound to gold nanoparticles and their extent of hybridization with complementary oligonucleotides in solution. Oligonucleotide surface coverages of hexanethiol 12-mer oligonucleotides on gold nanoparticles (34 +/- 1 pmol/cm2) were significantly higher than on planar gold thin films (18 +/- 3 pmol/cm2), while the percentage of hybridizable strands on the gold nanoparticles (1.3 +/- 0.3 pmol/cm2, 4%) was lower than for gold thin films (6 +/- 2 pmol/cm2, 33%). A gradual increase in electrolyte concentration over the course of oligonucleotide deposition significantly increases surface coverage and consequently particle stability. In addition, oligonucleotide spacer sequences improve the hybridization efficiency of oligonucleotide-modified nanoparticles from approximately 4 to 44%. The surface coverage of recognition strands can be tailored using coadsorbed diluent oligonucleotides. This provides a means of indirectly controlling the average number of hybridized strands per nanoparticle. The work presented here has important implications with regard to understanding interactions between modified oligonucleotides and metal nanoparticles, as well as optimizing the sensitivity of gold nanoparticle-based oligonucleotide detection methods.

Impairment of NF-kappaB activation and modulation of gene expression by calpastatin

To address the involvement of the calpain system in both basal and silica-induced nuclear factor (NF)-kappaB activation, several human bronchial epithelial cell lines were established in which an intracellular inhibitor of calpain, calpastatin, was stably expressed. Reduced basal and silica-induced inhibitor (IkappaBalpha) degradation and NF-kappaB activation were observed in cells stably overexpressing calpastatin. In addition, the cells in which calpain was constitutively inhibited by the overexpression of calpastatin exhibited a notable morphological change. Whereas empty vector-transfected cells displayed a morphology indistinguishable from that of parental cells, cells overexpressing calpastatin exhibited a mosaic morphological change with reduced formation of lamella 30 min after the cells were seeded. Genefilter microarray experiments, in which 3,965 human genes can be evaluated for their expression at the same time, showed that calpastatin downregulated genes encoding several membrane-associated proteins or nuclear proteins and upregulated genes of collagen alpha2, DAZ, and mitochondrial capsule selenoprotein. These results suggest that, in addition to their proteolytic activities on cytoskeletal proteins and other cellular regulatory proteins, calpain-calpastatin systems can also affect the expression levels of genes encoding structural or regulatory proteins.

Biochemical markers and skeletal metastases

BACKGROUND

Skeletal metastases are common occurrences in patients with malignancies such as breast and prostate carcinoma, but they are difficult to diagnose nonradiologically, and treatment is difficult to follow clinically. Recent developments suggest that biochemical markers of bone remodeling, such as the bone collagen breakdown product N-telopeptide and the bone formation marker known as bone specific alkaline phosphatase, hold great promise as clinical tools for the management of patients with metastatic bone disease.

METHODS

Serum levels of the bone formation marker known as bone specific alkaline phosphatase (BAP), along with serum levels of the bone collagen breakdown product carboxyterminal telopeptide of Type I collagen (ICTP) and urine levels of pyridinoline (PYD), deoxypridinoline (DPD), and N-telopeptide (NTx), were measured in a large cohort of patients with newly diagnosed or progressive cancer of the breast, prostate, lung, and other sites. Bone marker levels were correlated with the presence or absence of bone scan-documented metastases; metastatic disease extension in terms of the number of skeletal sites involved; and the type of lesion, whether blastic or lytic. Sites examined included the pelvis, spine, skull, ribs, and long bones.

RESULTS

All of the bone markers examined, including BAP and NTx, were abnormally elevated in a high proportion of patients with confirmed metastases to bone. Urine NTx levels and bone specific alkaline phosphatase were significantly correlated with the number of skeletal sites involved, and a significant correlation between marker level and extent of skeletal involvement was also observed. In addition, both markers were higher in patients with a blastic disease presentation than in patients with osteolytic lesions.

CONCLUSIONS

Biochemical markers of bone resorption and bone formation are abnormally raised in the blood and urine of patients with metastatic bone disease. Markers of bone collagen breakdown, such as N-telopeptide, as well as markers of osteoblast function, such as bone specific alkaline phosphatase, appear to be of use in assessing and managing patients with malignancies that metastasize to bone. In this study, both NTx and BAP showed a significant correlation with both the presence of bone metastases and the extent of skeletal involvement. Biochemical markers of bone remodeling can also be used to guide decision making regarding the treatment of metastatic bone disease and to determine the effectiveness of therapy for patients with cancer to bone whose broad-based symptoms make it difficult to discern true response to therapy.

Rapid maturation of the reproductive axis during perimenarche independent of body composition

The development of the reproductive axis is thought to be a gradual process, but our understanding of the complex endocrine changes that accompany the transition from premenarche to reproductive life in women has been hampered by the paucity of longitudinal studies. We studied 112 premenarchal Caucasian females at 6-month intervals over 4 yr and obtained a detailed reproductive and dietary history. We quantified reproductive hormones in 24-h urine collections as a measure of daily output and measured body composition biometrically and with the use of dual energy x-ray absortiometry scans. The percent body fat did not change appreciably in the study period (range, 21-24%) and was unrelated to menarche. Sex steroid and gonadotropin levels changed exponentially in the year approaching menarche. FSH levels peaked at menarche and then progressively declined thereafter. Estradiol output increased rapidly in the year approaching menarche and then plateaued thereafter. The frequency of menstrual bleeding increased rapidly and plateaued at 1 yr postmenarche. At 1 yr, 65% of these adolescent women had established a pattern of 10 or more menstrual episodes/yr, and by 3 yr postmenarche this figure exceeded 90%. There were no significant changes in dietary intake of protein, carbohydrate, or fat in the same period. Menarche occurs as a result of rapid maturation of the reproductive axis and heralds the reestablishment of a negative sex steroid feedback loop that parallels the adult threshold. These events appear to develop independent of changes in body composition and diet, but may reflect the improved nutrition and socioeconomic status of the late 20th century.

Involvement of 5'-flanking kappaB-like sites within bcl-x gene in silica-induced Bcl-x expression

The present study investigated the involvement of the transcription factor NF-kappaB in the expression of an anti-apoptotic gene, bcl-x, using a murine macrophage cell line and peritoneal macrophages from both wild type (p50(+/+)) and NF-kappaB p50 gene knockout (p50(-/-)) mice. Increased expression of Bcl-x protein was observed in native and silica-exposed p50(-/-) macrophages in which the NF-kappaB p65-containing complex was predominantly induced. Co-transfection experiment using a bcl-x promoter reporter construct and an expression vector for NF-kappaB p50 or p65 indicates that p65, but not p50, up-regulates the promoter activity of the bcl-x gene. DNA sequence analysis revealed that there are several kappaB-like sites within the 5'-flanking region of the bcl-x gene. Electrophoretic mobility shift assay suggested differences in binding of the NF-kappaB complexes to these putative NF-kappaB binding sites of the bcl-x gene.

Self-assessment of physical sexual maturation in boys and girls with delayed puberty

We studied 49 boys and girls with delayed physical sexual maturation during treatment with sex steroids. We found significant agreements, but also some disagreements between physicians' and subjects' Tanner sexual maturity ratings. We found neither effects of treatment with sex steroids nor gender differences, comparing ratings between physicians and patients.

Alpha-difluoromethylornithine as treatment for metastatic breast cancer patients

DFMO (alpha-difluoromethylornithine) is an oral irreversible inhibitor of ornithine decarboxylase, the first rate-limiting enzyme in polyamine synthesis. DFMO has been shown to have antiproliferative effects against several human cancers, and some studies have suggested that DFMO may have pro-apoptotic and anti-invasive properties as well. DFMO is well tolerated with minimal toxicity but has been associated with ototoxicity with prolonged daily administration. We conducted a Phase I/II tolerability, pharmacokinetic, and efficacy study of high-dose DFMO in metastatic breast cancer patients. Twenty-one patients were treated with 4800 mg of DFMO p.o. three times a day for 14 days, followed by a 2-week drug holiday on a 28-day cycle. Urinary polyamine and blood DFMO levels were measured at multiple time points during therapy. High-dose DFMO was well tolerated, and no clinically significant ototoxicity was noted. No patient achieved an objective antitumor response; however, one patient with heavily pretreated liver metastases has achieved stable disease for 18 months to date on DFMO. Putrescine, spermine, and spermidine urinary levels were suppressed with DFMO treatment and remained low during the 2-week drug holiday. High-dose DFMO on a schedule of 2 weeks on treatment followed by 2 weeks off is well tolerated, is not associated with ototoxicity, and leads to sustained suppression of urinary polyamine levels. Although not an active cytotoxic agent for metastatic breast cancer, the intriguing prolonged growth arrest of liver metastases in one patient highlights the potential clinical growth inhibitory properties of DFMO. We believe that DFMO is worthy of study as adjuvant therapy in primary breast cancer patients and as a chemopreventive agent.

Joint basal and pulsatile hypersecretory mechanisms drive the monotropic follicle-stimulating hormone (FSH) elevation in healthy older men: concurrent preservation of the orderliness of the FSH release process: a general clinical research center study

To appraise the neuroendocrine mechanisms that underlie a selective (monotropic) elevation of serum FSH concentrations in healthy older men, we sampled blood in 11 young (ages 21-34) and 8 older men (ages 62-72) men every 2.5 min overnight. Serum FSH concentrations were quantitated in an automated, high-sensitivity, chemiluminescence-based assay. Rates of basal and pulsatile FSH secretion were estimated by deconvolution analysis, and the orderliness of the FSH release process via quantitated the approximate entropy statistic. Statistical analysis revealed that healthy older men manifest dual neuroendocrine hypersecretory mechanisims; specifically, a 2-fold increase in the basal (nonpulsatile) FSH secretion rate, and a concurrent 50% amplification of FSH secretory burst mass (and amplitude). The regularity or orderliness of ad seriatim FSH release is preserved in older individuals. We postulate that higher basal FSH secretion in older men is a consequence of reduced testosterone negative feedback, whereas amplified FSH secretory burst mass reflects net enhanced stimulation of gonadotrope cells by endogenous FSH secretagogues (e.g. GnRH and/or activin). The foregoing specific mechanisms driving heightened FSH secretion in older men contrast with the lower-amplitude pulsatility and more disorderly patterns of LH release in the same individuals. Thus, the present data illuminate an age-dependent disparity in the disruption of FSH neuroregulation in the aging male.

Vanadate induction of NF-kappaB involves IkappaB kinase beta and SAPK/ERK kinase 1 in macrophages

The present studies investigated the signaling pathways of vanadate, a vanadium ion with +5 oxidation state, to activate NF-kappaB transcription factor, a pivotal regulator of inflammatory responses. Treatment of macrophages with vanadate results in the activation of both NF-kappaB and c-Jun N-terminal kinase (JNK). The activity of a recently identified cellular kinase, IkappaB kinase-beta (IKKbeta), was significantly elevated concomitant with the increased degradation of IkappaBalpha and enhanced NF-kappaB activity in cells exposed to vanadate. To determine whether the IKK pathway and JNK pathway are interconnected or bifurcate upon vanadate stimulation, cells were transfected with either a kinase inactive form of IKKbeta or a kinase inactive form of SAPK/ERK kinase 1 (SEK1). Inactive IKKbeta was able to block vanadate-induced degradation of IkappaBalpha, yet it was unable to influence the activation of JNK by vanadate. Conversely, blockage of JNK activation by transfection of a kinase-inactive form of SEK1 resulted in partially inhibition of vanadate-induced IkappaBalpha degradation. Both vanadate-induced degradation of IkappaBalpha and activation of JNK were potently inhibited by pretreatment of cells with N-acetylcysteine or dimercaprol. These results demonstrate that early activation of stress kinases or change of cellular redox states plays a key role in vanadate-induced activation of NF-kappaB and JNK.

Nitric oxide inhibits HIV tat-induced NF-kappaB activation

To evaluate the roles of nitric oxide (NO) on human immunodeficiency virus (HIV) Tat-induced transactivation of HIV long terminal repeat (HIV-LTR), we examined the effect of NO in the regulation of nuclear factor (NF)-kappaB, a key transcription factor involved in HIV gene expression and viral replication. In the present study, we demonstrate that HIV Tat activates NF-kappaB and that this activation can be attenuated by endogenous or exogenous NO. Inhibition of endogenous NO production with the NO synthase (NOS) inhibitor L-NMMA causes a significant increase in Tat-induced NF-kappaB activity. In addition, NO attenuates signal-initiated degradation of IkappaBalpha, an intracellular inhibitor of NF-kappaB, and blocks the DNA binding activity of the NF-kappaB p50/p50 homodimer and p50/p65 heterodimer. To determine how NO is induced by HIV Tat, reverse transcription polymerase chain reaction was used to demonstrate the induction of NOS-2 and NOS-3 mRNA by Tat. Although a putative NF-kappaB binding site was identified in the -74 GGAGAGCCCCC -64 region of the NOS-3 gene promoter, gel mobility shift assays and site-directed mutation analyses suggest that the putative NF-kappaB site is not of primary importance. Rather, several Sp-1 sites adjoining the putative NF-kappaB binding site in the promoter region of NOS-3 gene are required for the induction of NOS-3 gene expression by Tat.

Bone mineral density and body composition in lean women with polycystic ovary syndrome

OBJECTIVE

To examine bone mineral density (BMD) and fat distribution in lean women with polycystic ovary syndrome (PCOS) compared with matched control women.

DESIGN

Controlled clinical study.

SETTING

An academic clinical research center.

PATIENT(S)

Twelve non-Hispanic white women with PCOS and a body mass index of <26 and 10 healthy control women matched for age, ethnicity, and weight.

INTERVENTION(S)

Biometric measures, blood sample collection, and total body/regional bone density and fat analysis were performed.

MAIN OUTCOME MEASURE(S)

Serum levels of androgens, glucose, and insulin were measured. Bone density and fat distribution were measured by total body dual-energy x-ray absorptiometry.

RESULT(S)

Androgen levels were elevated significantly in the lean women with PCOS compared with the controls. There was no statistically significant difference in total body BMD between the two groups. A significant increase in BMD was noted in the left arm, right arm, and left ribs of the lean PCOS group. Evaluation of upper body BMD showed a significant correlation between testosterone levels and BMD. No statistically significant differences were noted in body fat distribution, although the lean PCOS group tended to have lower mean percentages of body fat.

CONCLUSION(S)

Lean women with PCOS have regional differences in BMD, with significantly increased BMD in the upper skeleton compared with control women.

Aromatase within the breast

In situ aromatization and enhanced uptake of estradiol from plasma are two potential mechanisms for maintenance of high concentrations of estradiol found in breast tumors of postmenopausal patients. To test the relative importance of these two mechanisms, a nude mouse model was established by inoculating aromatase (A+) and/or sham (A-) transfected MCF-7 cells into ovariectomized mice. Postmenopausal hormonal status was simulated by providing estradiol Silastic implants which clamped plasma estradiol levels at 5-20 pg/ml. We demonstrated that in situ aromatization rather than the uptake mechanism is the key determinant of tumor estradiol levels and tumor growth rate under conditions reflecting the postmenopausal state. The importance of intratumoral aromatase was also suggested by the findings that long-term estrogen deprivation increases sensitivity to estradiol and enhances aromatase activity in MCF-7 cells. The results of our in vivo and in vitro studies suggest that complete blockade of in situ aromatization in the breast would provide added benefit to postmenopausal breast cancer patients, especially those who relapse from antiestrogen therapy.

New insights into the role of nuclear factor-kappaB, a ubiquitous transcription factor in the initiation of diseases

Nuclear factor-kappaB (NF-kappaB) is a ubiquitous transcription factor that governs the expression of genes encoding cytokines, chemokines, growth factors, cell adhesion molecules, and some acute phase proteins in health and in various disease states. NF-kappaB is activated by several agents, including cytokines, oxidant free radicals, inhaled particles, ultraviolet irradiation, and bacterial or viral products. Inappropriate activation of NF-kappaB has been linked to inflammatory events associated with autoimmune arthritis, asthma, septic shock, lung fibrosis, glomerulonephritis, atherosclerosis, and AIDS. In contrast, complete and persistent inhibition of NF-kappaB has been linked directly to apoptosis, inappropriate immune cell development, and delayed cell growth. Therefore, development of modulatory strategies targeting this transcription factor may provide a novel therapeutic tool for the treatment or prevention of various diseases.

Effect of the potent aromatase inhibitor fadrozole hydrochloride (CGS 16949A) in postmenopausal women with breast carcinoma

BACKGROUND

Fadrozole hydrochloride (CGS 16949A) is a highly potent, nonsteroidal aromatase inhibitor that significantly lowers estrogen levels in postmenopausal women and can be effective therapy for patients with advanced hormone-dependent breast carcinoma. Circulating estradiol, estrone, and estrone sulfate are reduced to undetectable levels within weeks of the initiation of therapy. Before this study, it was not known whether this decrease in serum estrogen levels results in altered parameters associated with cardiovascular disease. The authors examined the levels of several critical blood parameters that are important to cardiovascular risk for heart disease and thromboembolic disorders in patients treated with fadrozole.

METHODS

Cholesterol, triglyceride, low density lipoprotein (LDL), high density lipoprotein (HDL), very low density lipoprotein (VLDL), antithrombin III, protein C, protein S, and fibrinogen were serially measured in 21 postmenopausal women with advanced breast carcinoma treated with various doses of fadrozole (1.8 mg/day, n=3; 2.0 mg/day, n=13; 4.0 mg/day, n=5) over 3-24 months (mean, 15.8 months). A repeated measure analysis of variance was applied to each cardiovascular variable to assess changes in the response over time. Analyses were performed separately for each dose group and were also pooled over the dose groups.

RESULTS

There was no statistically significant change over time in lipid parameters, namely, total cholesterol (P=0.57), triglyceride (P=0.27), LDL (P=0.99), HDL (P=0.30), and VLDL (P=0.43), over the 24 months of therapy. There were also no significant changes in coagulation factors, namely, antithrombin III (P=0.41), protein C (P=0.49), or protein S (P=0.31), over the 24 months. However, an increase in fibrinogen that occurred over time did reach statistical significance (P=0.011).

CONCLUSIONS

With the exception of acute phase reactant fibrinogen, this study did not identify an increase in parameters associated with cardiovascular disease in women treated with fadrozole, a potent aromatase inhibitor.

Determinants of tissue estradiol levels and biologic responsiveness in breast tumors

Estradiol stimulates the growth of breast tumor cells in both pre- and post menopausal women. Following the menopause, the levels of estradiol in breast tumor tissues are similar to those from tumors obtained prior to cessation of ovarian function, even though plasma estrogen levels are 10-50 fold lower in post- than in premenopausal women. These observations suggested the possibility of enhanced estradiol uptake from plasma or in situ synthesis in post-menopausal women. We systematically studied these possibilities in a series of model systems. Initially we demonstrated a very high affinity estradiol binding site in tissues from castrated rats. Enhanced uptake occurred under conditions of low plasma estrogen levels when compared to animals with higher estradiol levels. In situ synthesis also occurred both through the sulfatase and aromatase pathways. In further studies, we compared uptake from plasma with in situ synthesis via aromatase in a nude mouse model. Under the conditions utilized, in situ synthesis resulted in much higher tissue estradiol levels and tumor growth rates than did uptake from plasma. During these studies we demonstrated that tumors deprived of estradiol developed mechanisms rendering them more sensitive to estrogen. This involved the ability of cells to adapt to estradiol deprivation to allow them to be responsive to four log lower amounts of estrogen than when studied under wild type conditions. In addition, cells adapted by increasing their level of aromatase and thus developing the capability to become more sensitive to estrogen precursors. Taken together, these studies demonstrate that breast cancer tissue is highly plastic and can adapt to conditions of estrogen deprivation via a variety of mechanisms.

Collagen cross-link excretion during space flight and bed rest

Extended exposure to weightlessness results in bone loss. However, little information exists as to the precise nature or time course of this bone loss. Bone resorption results in the release of collagen breakdown products, including N-telopeptide and the pyridinium (PYD) cross-links, pyridinoline and deoxypyridinoline. Urinary pyridinoline and deoxypyridinoline are known to increase during bed rest. We assessed excretion of PYD cross-links and N-telopeptide before, during, and after long (28-day, 59-day, and 84-day) Skylab missions, as well as during short (14-day) and long (119-day) bed-rest studies. During space flight, the urinary cross-link excretion level was twice those observed before flight. Urinary excretion levels of the collagen breakdown products were also 40-50% higher, during short and long bed rest, than before. These results clearly show that the changes in bone metabolism associated with space flight involve increased resorption. The rate of response (i.e. within days to weeks) suggests that alterations in bone metabolism are an early effect of weightlessness. These studies are important for a better understanding of bone metabolism in space crews and in those who are bedridden.

The effect of sex hormone replacement therapy on behavior problems and moods in adolescents with delayed puberty

OBJECTIVE

The objective of this clinical study was to determine the effects of sex steroids on behavior and mood in adolescents with hypogonadism.

STUDY DESIGN

The experimental design consisted of a randomized, double-blind, placebo-controlled, crossover trial lasting for 21 months. The study group consisted of 39 boys and 16 girls recruited from a pediatric endocrine clinic for delayed puberty. Depo-testosterone (to boys) or conjugated estrogens (to girls) was administered in 3-month blocks, alternating with placebo, at 3 dose levels approximating early, middle, and late pubertal amounts. The Child Behavior Checklist, Youth Self Report, Differential Emotion Scale, and Daily Mood Diary were administered after each placebo and treatment period to ascertain the effect of sex steroids on self- and parent-reported behavior problems and moods.

RESULTS

The data demonstrated only one significant treatment effect, namely, an increase in withdrawn behavior problems during administration of low-dose estrogen in girls. There were no consistent sex differences.

CONCLUSION

These results demonstrate that administered testosterone or estrogen has minimal effects on behavior problems or mood in adolescents.

Effects of estrogen or testosterone on self-reported sexual responses and behaviors in hypogonadal adolescents

The purpose of this study was to investigate the effects of administration of sex steroids on self-reported sexual responses and behaviors in hypogonadal adolescents. We used a randomized, double blind, placebo-controlled, cross-over, clinical trial as the experimental design. The subjects were 39 boys and 16 girls with delayed puberty. We treated girls with oral conjugated estrogen and boys with testosterone enanthate in 3 dose levels intended to simulate early, middle, and late pubertal levels. We administered a modification of the Udry sexual behavior questionnaire after each 3-month placebo and treatment period to detect the effect of sex steroids on self-reported sexual behaviors and responses. We employed a strict intent to treat statistical analytical model. The data showed significant effects of the administration of testosterone to boys causing increases in nocturnal emission and touching behaviors at the mid- and high doses. No other treatment effects on sexual behaviors or responses were seen in boys. For girls, there was a significant increase in necking caused by the administration of estrogen only at the late pubertal dose. No other treatment effects on sexual behaviors or responses were seen in girls. We noted some gender differences for thinking about sex, sexual "turn-on," and the nature of sexual behavior. The administration of physiological doses of sex steroids to boys or girls with delayed puberty have few effects on sexual behaviors and responses.

Comparative rates of androgen production and metabolism in Caucasian and Chinese subjects

Clinically apparent prostate cancer occurs more commonly among Caucasians living in Western countries than in Chinese in the Far East. Prior studies demonstrated diminished facial and body hair and lower levels of plasma 3 alpha-androstanediol glucuronide and androsterone glucuronide in Chinese than in Caucasian men. Based upon these findings, investigators postulated that Chinese men could have diminished 5 alpha-reductase activity with a resultant decrease in prostate tissue dihydrotestosterone levels and clinically apparent prostate cancer. An alternative hypothesis suggests that decreased 3 alpha-androstanediol glucuronide and androsterone glucuronide levels might reflect reduced production of androgenic ketosteroid precursors as a result of genetic or environmental factors. The present study examined 5 alpha-reductase activity, androgenic ketosteroid precursors, and the influence of genetic and environmental/dietary factors in groups of Chinese and Caucasian men. We found no significant differences in the ratios of 5 beta-:5 alpha-reduced urinary steroids (a marker of 5 alpha-reductase activity) between Chinese subjects living in Beijing, China, and Caucasians living in Pennsylvania. To enhance the sensitivity of detection, we used an isotopic kinetic method to directly measure 5 alpha-reductase activity and found no difference in testosterone to dihydrotestosterone conversion ratios between groups. Then, addressing the alternative hypothesis, we found that the Caucasian subjects excreted significantly higher levels of individual and total androgenic ketosteroids than did their Chinese counterparts. To distinguish genetic from environmental/dietary factors as a cause of these differences, we compared Chinese men living in Pennsylvania and a similar group living in Beijing, China. We detected a reduction in testosterone production rates and total plasma testosterone and sex hormone-binding levels, but not in testosterone MCRs in Beijing Chinese as a opposed to those living in Pennsylvania. Comparing Pennsylvania Chinese with their Caucasian counterparts, we detected no significant differences in total testosterone, free and weakly bound testosterone, sex hormone-binding globulin levels, and testosterone production rates. Taken together, these studies suggest that environmental/dietary, but not genetic, factors influence androgen production and explain the differences between Caucasian and Chinese men.

Effect of CGS 20267 on ovarian aromatase and gonadotropin levels in the rat

Aromatase catalyzes the rate limiting step that converts androgens to estrogens. Postmenopausal women with hormone dependent breast cancer respond to first generation aromatase inhibitors such as aminoglutethimide with a marked suppression of circulating estradiol levels. In contrast, premenopausal women appear to be resistant to first generation aromatase inhibitors. The inability to block ovarian aromatase results from the low affinity of first generation inhibitors for the active site of the enzyme. Under these circumstances, the high substrate levels in the premenopausal ovary compete effectively with these inhibitors and do not allow binding of inhibitor to the active site of the enzyme. Second and third generation aromatase inhibitors with higher affinity for aromatase have now been developed and potentially could block ovarian aromatase. To test this possibility, we administered CGS 20267 (letrozole), a highly potent aromatase inhibitor, to cycling female rats. A dose dependent inhibition of uterine weight occurred with maximum effects produced by the 5 mg/kg/day dosage. During a period of 4 weeks, uterine weight was reduced to levels induced by ovariectomy. Ovarian tissue estradiol levels were inhibited by approximately 80%. As a reflection of inhibition of ovarian aromatase activity, the levels of androstenedione in the ovary increased by an order of magnitude. Both LH and FSH plasma levels increased but not to those observed after ovariectomy. The rise in gonadotropin levels induced a statistically significant but relatively small increase in ovarian weights. These results demonstrate the ability to persistently block ovarian aromatase activity in cycling rats with a potent aromatase inhibitor. This study provides a rationale for clinical trials of potent aromatase inhibitors in pre-menopausal women with breast cancer.

In situ aromatization enhances breast tumor estradiol levels and cellular proliferation

The high concentrations of estradiol (E2) found in breast tumors of postmenopausal women could be the result of enhanced uptake from plasma or in situ aromatization of androgens to estrogens. To test the relative importance of these two mechanisms, a model system allowing precise distinction between each is required. Such a model was established using aromatase (A+)- and sham (A-)-transfected MCF-7 cells inoculated into ovariectomized (OVX) nude mice. To validate the model, the confounding effect of peripheral aromatization was first excluded experimentally. A- cells were inoculated into OVX mice as homoimplants (A- cells on both flanks) or heteroimplants (A- cells on one flank and A+ cells on the other), and growth of A- cells in response to exogenous aromatase substrate, androstenedione (delta4A), was evaluated. A- cells did not grow in either group during the 8 weeks of observation, indicating the lack of peripheral aromatization in OVX mice. The biological effects of in situ aromatization were then directly examined. We found that A+ cells in the heteroimplant group grew rapidly, and that the average weight of A+ tumor was 7.6-fold larger and tissue E2 concentration was 3-4-fold higher than A- tumors grown in the same animals. These results demonstrate that in situ aromatization rather than uptake can be a determinant of tumor E2 content and growth stimulation. An additional experiment was then designed to evaluate the relative importance of in situ synthesis versus uptake under conditions reflecting postmenopausal physiology. Groups of OVX mice bearing A+ cells received E2 Silastic implants to clamp plasma levels at 5, 7, 10, and 20 pg/ml or delta4A by injection. The highest tumor E2 concentration and growth rate were found in the group receiving delta4A. E2 delivered by Silastic implants always produced lower tissue E2 levels and tumor growth rates than resulted from in situ synthesis. These data provide direct evidence that under physiological conditions reflecting those in postmenopausal women, in situ aromatization in breast tumor makes a major contribution to tissue E2 content. As further validation that our experimental paradigm models the postmenopausal state, we studied OVX animals not given delta4A as substrate. A+ cells also grew under these conditions, and the aromatase inhibitor 4-hydroxyandrostenedione reduced both tumor E2 level and growth rate, providing additional evidence of the importance of in situ synthesis. These studies provide the first direct evidence that in situ synthesis of E2 in breast tumors, as opposed to peripheral aromatization and uptake from plasma, can enhance tissue E2 levels and stimulate tumor growth.

Role of hydroxyl radical in silica-induced NF-kappa B activation in macrophages

Nuclear transcription factor kappa B (NF-kappa B) is a multiprotein complex that regulates a variety of genes important for immunity and inflammation. The present study investigates the silica-induced activation of this transcription factor in mouse macrophage cell line RAW 264.7 cells, the role of free radical reactions in the mechanism of the activation, and its possible inhibition. Tetrandrine, a benzylisoquinoline alkaloid, which has been used as an antifibrotic drug to treat the lesions of silicosis and has been characterized as a hydroxyl radical (.OH) scavenger, inhibited the NF-kappa B activation induced by silica, lipopolysaccharide (LPS), and phorbol 12-myristate 13-acetate (PMA). Catalase, metal chelator, deferoxamine, and the silanol group (SiOH) blocker, poly(2-vinylpyridine-N-oxide) (PVPNO), also inhibited silica-induced NF-kappa B activation. Electron spin resonance (ESR) spin trapping measurements show that both deferoxamine and PVPNO decreased silica-mediated .OH radical generation from H2O2. It is shown that Fe(II) and not Fe(III) is able to cause NF-kappa B activation. The antioxidant, ascorbate, attenuated the NF-kappa B activation induced by silica but not by LPS. The .OH radical scavenger, sodium formate, inhibited NF-kappa B activation induced by silica but had only a minor effect on NF-kappa B activation induced by LPS. The results indicate that silica-mediated free radical generation via the Fenton or Fenton-like reaction (M(n)+ + H2O2-->M(n + 1)+ + OH- + .OH) and silanol groups on the silica surface play an important role in silica-induced NF-kappa B activation.

Estrogen or testosterone increases self-reported aggressive behaviors in hypogonadal adolescents

A randomized, double-blinded, placebo-controlled cross-over clinical trial was used to determine the role of sex steroids on the development of aggressive behaviors in 35 boys and 14 girls. Depo-testosterone (to boys) or conjugated estrogens (to girls) was administered in 3-month blocks alternating with placebo at three dose levels approximating early, middle and late pubertal amounts. The Olweus Multifaceted Aggression Inventory was administered after each placebo and treatment period to ascertain the effect of sex steroids on self-reported aggressive behaviors. We employed a strict intent-to-treat analytical model. The data demonstrated significant hormone effects on physical aggressive behaviors and aggressive impulses, but not in verbal aggressive behaviors nor aggressive inhibitions in both boys and girls. These results are the first to causally relate the administration of physiological doses of sex steroids to changes in aggressive behaviors in adolescents.

Calpain contributes to silica-induced I kappa B-alpha degradation and nuclear factor-kappa B activation

Both silica and lipopolysaccharide (LPS) induce a rapid degradation of I kappa B alpha, an intracellular inhibitor of the nuclear factor (NF)-kappa B transcription factor. In this report, we demonstrate that MG132, a relatively specific proteasome inhibitor, is capable of suppressing LPS-induced I kappa B alpha degradation and NF-kappa B activation in mouse macrophage line RAW 264.7 cells, but is unable to influence the same induction produced by silica. In contrast, the lysosome inhibitor chloroquine has little effect on I kappa B alpha degradation induced by either silica or LPS. In fact, chloroquine enhances the signal-induced nuclear expression of NF-kappa B p50/p65 heterodimer by inhibiting the resynthesis of I kappa B alpha. With the use of transient transfection of a plasmid that expresses calpastatin, a natural inhibitor for calpain, the silica-induced degradation of I kappa B alpha and NF-kappa B activation was attenuated. In contrast, no inhibition of LPS-induced I kappa B alpha degradation and NF-kappa B activation was observed by the overexpression of calpastatin. This suggests that calpain contributes to silica-induced I kappa B alpha degradation and NF-kappa B activation but not to LPS-induced I kappa B alpha degradation and NF-kappa B activation.

Estrogen production via the aromatase enzyme in breast carcinoma: which cell type is responsible?

Studies of breast tumor homogenates from women with breast cancer have demonstrated the synthesis of estrogens in situ through the enzyme aromatase. The present series of investigations sought to determine which cell type within the tumor is responsible for local estrogen biosynthesis, and whether or not the amount produced is biologically important. Accordingly, we utilized an indirect immunohistochemical scoring method (H-score) to determine the relative amount of enzyme present in tumor epithelial and stromal cells. This revealed a value of 13 for tumor stromal cells and 4.8 for the epithelial component. Contributing to this difference is the fact that a greater percentage of cells in the tumor were stromal (45%) than epithelial (37%). To obtain direct evidence that tumor stromal cells could synthesize estrogens, we isolated and grew these cells in tissue culture. Stromal cells originating from within the tumor could be stimulated by known enhancers of transcription to produce nearly as much aromatase as is found in placental microsomes. Stromal cells isolated from benign tissue distal to the tumor exhibited properties similar to those of the tumor stroma. Epithelial cells, in contrast, did not respond to these enhancers and had low levels of aromatase basally. To obtain proof of the principle that local estrogen synthesis can be biologically meaningful, we measured tumor tissue estradiol levels and growth rates in aromatase-transfected MCF-7 cells implanted into nude mice. Local synthesis resulted in tumor levels ranging from 300 to 800 pg/g and growth rates substantially higher than in non-aromatase-containing tumors. These data suggest that tumor stromal cells contribute the major portion of estrogen synthesized in tumors, and that this local synthesis can increase tumor estradiol levels and growth rates.

Involvement of NF-kappaB in silica-induced cyclooxygenase II gene expression in rat alveolar macrophages

The role of nuclear factor (NF)-kappaB transcription factor in silica-induced cyclooxygenase (COX) II gene expression was examined in the rat alveolar macrophage cell line NR8383. Our results indicate that NF-kappaB can be activated in this cell line by silica exposure. Suppression of NF-kappaB activation in these cells leads to an attenuation of COX II mRNA accumulation induced by silica. Using an electrophoretic mobility shift assay and a reporter gene assay, we provide evidence that at least two kappaB sites in the 5'-flanking region of the rat COX II gene are involved for silica-induced transcriptional control of the COX II gene. The first motif, -404 GGGGATTCCC -395, is absolutely conserved in sequence and is localized in a similar position among the COX II genes found in humans, rats, and mice. The second motif, -91 GGGGAAAGCC -82, was conserved only in the mouse and rat COX II genes in sequence and in location. Aspirin, a COX inhibitor, was shown to suppress silica-induced NF-kappaB activation. However, prostaglandin E2, one of the important downstream reaction products catalyzed by the COX enzyme, was also shown to attenuate silica-induced NF-kappaB activation by retarding the degradation of silica-induced inhibitor NF-kappaB. These results suggest that an interdependent regulation may exist between NF-kappaB activation and COX or its products.

Ornithine decarboxylase over-expression stimulates mitogen-activated protein kinase and anchorage-independent growth of human breast epithelial cells

In these experiments we tested the hypothesis that constitutive activation of polyamine(PA) biosynthesis may contribute to mammary carcinogenesis. Spontaneously immortalized normal human MCF-10A breast epithelial cells were infected with the retroviral vector pLOSN containing a cDNA which codes for a truncated and more stable ornithine decarboxylase (ODC), the rate-limiting enzyme in PA synthesis. Upon chronic selective pressure with alpha-difluoromethyl-ornithine (DFMO) (an irreversible inhibitor of ODC), infected MCF-10A cells exhibited an approximately 250-fold increase in ODC activity, which persisted despite discontinuation of DFMO. ODC-over-expressing MCF-10A cells showed a modest decrease in S-adenosylmethionine decarboxylase and an increase in spermidine/spermineN1-acetyltransferase. Analysis of cellular PA profile revealed a selective accumulation of putrescine without alterations in spermidine and spermine contents. Lesser degrees of increased ODC activity were obtained reproducibly by re-exposing the cells to incremental small doses of DFMO. We observed a bell-shaped dose-related positive effect of ODC activity on clonogenicity in soft agar of MCF-10A cells. Since anchorage-dependent growth was actually reduced, such positive influence on this feature of transformation was not a non-specific consequence of a growth advantage provided by ODC over-expression. In addition, we observed a close parallelism between the dose-dependent effects of ODC expression on clonogenicity and activity of the ERK-2 kinase, a central element of the MAPK cascade. Our data demonstrate an interaction between PA and the MAPK signalling pathway and suggest that the latter may be involved in ODC-induced transformation of mammary epithelial cells.

Tetrandrine inhibits signal-induced NF-kappa B activation in rat alveolar macrophages

Tetrandrine is a bisbenzylisoquinoline alkaloid isolated from a natural Chinese herbal medicine. While this alkaloid has been shown to exhibit antifibrotic and anti-inflammatory activities, its mechanism of action is unknown. The present study was designed to investigate the inhibitory effect of tetrandrine on NF-kappa B activation in the alveolar macrophage. Three different provocative stimuli were used to activate NF-kappa B in these cells. The results indicate that tetrandrine can inhibit the activation of NF-kappa B and NF-kappa B-dependent reporter gene expression by LPS, PMA, and silica in a dose-dependent manner. In contrast, at the doses used, tetrandrine did not interfere with Sp-1 DNA binding activity or Sp-1-dependent reporter gene expression in these cells. Western blot analysis suggests that the inhibitory effect of tetrandrine on NF-kappa B activation can be attributed to its ability to suppress signal-induced degradation of I kappa B alpha, a cytoplasmic inhibitor of the NF-kappa B transcription factor.

Ornithine decarboxylase over-expression stimulates mitogen-activated protein kinase and anchorage-independent growth of human breast epithelial cells

In these experiments we tested the hypothesis that constitutive activation of polyamine(PA) biosynthesis may contribute to mammary carcinogenesis. Spontaneously immortalized normal human MCF-10A breast epithelial cells were infected with the retroviral vector pLOSN containing a cDNA which codes for a truncated and more stable ornithine decarboxylase (ODC), the rate-limiting enzyme in PA synthesis. Upon chronic selective pressure with alpha-difluoromethyl-ornithine (DFMO) (an irreversible inhibitor of ODC), infected MCF-10A cells exhibited an approximately 250-fold increase in ODC activity, which persisted despite discontinuation of DFMO. ODC-over-expressing MCF-10A cells showed a modest decrease in S-adenosylmethionine decarboxylase and an increase in spermidine/spermineN1-acetyltransferase. Analysis of cellular PA profile revealed a selective accumulation of putrescine without alterations in spermidine and spermine contents. Lesser degrees of increased ODC activity were obtained reproducibly by re-exposing the cells to incremental small doses of DFMO. We observed a bell-shaped dose-related positive effect of ODC activity on clonogenicity in soft agar of MCF-10A cells. Since anchorage-dependent growth was actually reduced, such positive influence on this feature of transformation was not a non-specific consequence of a growth advantage provided by ODC over-expression. In addition, we observed a close parallelism between the dose-dependent effects of ODC expression on clonogenicity and activity of the ERK-2 kinase, a central element of the MAPK cascade. Our data demonstrate an interaction between PA and the MAPK signalling pathway and suggest that the latter may be involved in ODC-induced transformation of mammary epithelial cells.

Clinical usefulness of markers of bone degradation and formation

The evaluation and management of patients with metabolic bone disease has been enhanced in recent years by the availability and clinical application of new biochemical markers of bone degradation and bone formation. Traditionally, biochemical markers such as serum alkaline phosphatase activity and urinary hydroxyproline measurements have been used to facilitate the clinical monitoring of patients receiving therapy for metabolic bone diseases like Paget's disease and osteomalacia. The poor specificity and sensitivity of these older markers however, made it difficult to follow patient response to therapy with the more subtle bone diseases like osteoporosis and metastatic bone cancer. New advances in bone marker biology particularly with biochemical markers of bone resorption have renewed interest in the use of biochemical markers to manage patients with different forms of metabolic bone disease. Bone loss markers such as the pyridinium cross-links and associated telopeptides have expanded the application of bone markers to not only monitor therapy in patients with metabolic bone disease but to reliably predict the bone density response to anti-resorptive medications. These markers have also been used to identify patients at risk for fractures who have significant bone density loss as a result of bone disease or as a physiologic consequences of menopause. This report reviews the relevant, newer markers of bone turnover and their current clinical utility in patients with osteoporosis and metastatic bone disease.