The role of serum TGF-beta isoforms as potential markers of osteoporosis

Advanced biosensors for nanomaterial-based detection of transforming growth factor alpha and beta, a class of major polypeptide regulators

Transforming growth factors (TGFs) regulate several cellular processes including, differentiation, growth, migration, extracellular matrix production, and apoptosis. TGF alpha (TGF-α) is a heterogeneous molecule containing 160 amino acid residues. It is a potent angiogenesis promoter that is activated by JAK-STAT signaling. Whereas TGF beta (TGF-β) consists of 390-412 amino acids. Smad and non-Smad signaling both occur in TGF beta. It is linked to immune cell activation, differentiation, and proliferation. It also triggers pre-apoptotic responses and inhibits cell proliferation. Both growth factors have a promising role in the development and homeostasis of tissues. Defects such as autoimmune diseases and cancer develop mechanisms to modulate checkpoints of the immune system resulting in altered growth factors profile. An accurate amount of these growth factors is essential for normal functioning, but an exceed or fall behind the normal level is alarming as it is linked to several disorders. This demands techniques for TGF-α and TGF-β profiling to effectively diagnose diseases, monitor their progression, and assess the efficacy of immunotherapeutic drugs. Quantitative detection techniques including the emergence of biosensing technology seem to accomplish the purpose. Until the present time, few biosensors have been designed in the context of TGF-α and TGF-β for disease detection, analyzing receptor binding, and interaction with carriers. In this paper, we have reviewed the physiology of transforming growth factor alpha and beta, including the types, structure, function, latent/active forms, signaling, and defects caused. It involves the description of biosensors on TGF-α and TGF-β, advances in technology, and future perspectives.

Farnesyl diphosphate synthase promotes cell proliferation by regulating gene expression and alternative splicing profiles in HeLa cells

Farnesyl diphosphate synthase (FDPS), an essential enzyme involved in the mevalonate pathway, is implicated in various diseases, including multiple types of cancer. As an RNA-binding protein (RBP), FDPS is also involved in transcriptional and post-transcriptional regulation. However, to the best of our knowledge, transcriptome-wide targets of FDPS still remain unknown. In the present study, FDPS expression patterns in pan-cancer were analyzed. In addition, it was investigated how FDPS overexpression (FDPS-OE) regulates the transcriptome in HeLa cells. FDPS-OE increased the proliferation rate in HeLa cells by MTT assay. Using transcriptome-wide high throughput sequencing and bioinformatics analysis, it was found that FDPS upregulated the expression levels of genes enriched in cell proliferation and extracellular matrix organization, including the laminin subunit γ2, interferon-induced proteins with tetratricopeptide repeats 2 and matrix metallopeptidase 19 genes. According to alternative splicing (AS) analysis, FDPS modulated the splicing patterns of the bone morphogenic protein 1, semaphorin 4D, annexin A2 and sirtuin 2 genes, which are enriched in the cell cycle and DNA repair, and are related to cell proliferation. To corroborate the FDPS-regulated transcriptome findings, FDPS was overexpressed in human osteosarcoma cells. Differentially expressed genes and regulated AS genes in the cells were both validated by reverse transcription-quantitative PCR. The results suggested that, as an emerging RBP, FDPS may serve an important role in transcriptome profiles by altering gene expression and regulating AS. FDPS also affected the cell proliferation rate. These findings broaden the understanding of the molecular functions of FDPS, and the potential of FDPS as a target in therapy should be investigated.

Circulating TGF-β Pathway in Osteogenesis Imperfecta Pediatric Patients Subjected to MSCs-Based Cell Therapy

Osteogenesis Imperfecta (OI) is a rare genetic disease characterized by bone fragility, with a wide range in the severity of clinical manifestations. The majority of cases are due to mutations in COL1A1 or COL1A2, which encode type I collagen. There is no cure for OI, and real concerns exist for current therapeutic approaches, mainly antiresorptive drugs, regarding their effectiveness and security. Safer and effective therapeutic approaches are demanded. Cell therapy with mesenchymal stem cells (MSCs), osteoprogenitors capable of secreting type I collagen, has been tested to treat pediatric OI with encouraging outcomes. Another therapeutic approach currently under clinical development focuses on the inhibition of TGF-β pathway, based on the excessive TGF-β signaling found in the skeleton of severe OI mice models, and the fact that TGF-β neutralizing antibody treatment rescued bone phenotypes in those OI murine models. An increased serum expression of TGF-β superfamily members has been described for a number of bone pathologies, but still it has not been addressed in OI patients. To delve into this unexplored question, in the present study we investigated serum TGF-β signalling pathway in two OI pediatric patients who participated in TERCELOI, a phase I clinical trial based on reiterative infusions of MSCs. We examined not only the expression and bioactivity of circulating TGF-β pathway in TERCELOI patients, but also the effects that MSCs therapy could elicit. Strikingly, basal serum from the most severe patient showed an enhanced expression of several TGF-β superfamily members and increased TGF-β bioactivity, which were modulated after MSCs therapy.

An insight into the implications of estrogen deficiency and transforming growth factor β in antiepileptic drugs-induced bone loss

There have been a number of reports that chronic antiepileptic drug (AEDs) therapy is associated with abnormal bone and calcium metabolism, osteoporosis/osteomalacia, and increased risk of fractures. Bony adverse effects of long term antiepileptic drug therapy have been reported for more than four decades but the exact molecular mechanism is still lacking. Several mechanisms have been proposed regarding AEDs induced bone loss; Hypovitaminosis D, hyperparathyroidism, estrogen deficiency, calcitonin deficiency. Transforming growth factor-β (TGF- β) is abundant in bone matrix and has been shown to regulate the activity of osteoblasts and osteoclasts in vitro. All isoforms of TGF- β are expressed in bone and intricately play role in bone homeostasis by modulating estrogen level. Ovariectomised animal have shown down regulation of TGF- β in bone that could also be a probable target of AEDs therapy associated bone loss. One of the widely accepted hypotheses regarding the conventional drugs induced bone loss is hypovitaminosis D which is by virtue of their microsomal enzyme inducing effect. However, despite of the lack of enzyme inducing effect of certain newer antiepileptic drugs, reduced bone mineral density with these drugs have also been reported. Thus an understanding of bone biology, pathophysiology of AEDs induced bone loss at molecular level can aid in the better management of bone loss in patients on chronic AEDs therapy. This review focuses mainly on certain new molecular targets of AEDs induced bone loss.

An In Silico Model for the Prediction of Changes in Mineral Density in Cortical Bone Remodeling

An in silico model for the estimation of volumetric bone mineral density (vBMD) changes at a cortical bone site subjected to mechanobiological bone remodeling is proposed in this manuscript. Mechanisms of cell differentiation, receptor-ligand binding, mechanical signaling, and resorption or deposition of bone matrix were considered, therefore providing a comprehensive description of mechanobiological bone remodeling in the bone microenvironment and enabling the analysis of temporal evolution of disease or therapy scenarios. The proposed model is composed by five modules, namely, bone cells populations, mechanobiology, volume fractions and porosity, mineral density, and structural stiffness. The model is an extension of other models found in the literature because equations for the obtaining of cortical vBMD and the binding of parathyroid hormone (PTH) to parathyroid hormone 1 receptor are included. The proposed model showed a satisfactory agreement with the solutions of other in silico models found in the literature. Simulations of walking and running exercise routines were performed for the evaluation of model capability regarding the control of the numerical error and prediction of vBMD. The computational method used to solve the case study controlled the relative numerical error by less than 1 × 10-7 for approximately 1.7 × 106 time steps. The predicted values correlate with the concept of increasing BMD by vigorous physical activity; however, they contrast with the specific effect of physical activities on cortical vBMD.

Collagen and non-collagenous proteins molecular crosstalk in the pathophysiology of osteoporosis

Collagenous and non-collagenous proteins (NCPs) in the extracellular matrix, as well as the coupling mechanisms between osteoclasts and osteoblasts, work together to ensure normal bone metabolism. Each protein plays one or more critical roles in bone metabolism, sometimes even contradictory, thus affecting the final mechanical, physical and chemical properties of bone tissue. Anomalies in the amount and structure of one or more of these proteins can cause abnormalities in bone formation and resorption, which consequently leads to malformations and defects, such as osteoporosis (OP). The connections between key proteins involved in matrix formation and resorption are far from being elucidated. In this review, we resume knowledge on the crosstalk between collagen type I and selected NCPs (Transforming Growth Factor-β, Insulin-like Growth Factor-1, Decorin, Osteonectin, Osteopontin, Bone Sialoprotein and Osteocalcin) of bone matrix, focusing on their possible involvement and role in OP. The different elements of this network can be pharmacologically targeted or used for the design/development of innovative regenerative strategies to modulate a feedback loop in bone remodelling.

Effect of kidney-reinforcing and marrow-beneficial traditional Chinese medicine-intervened serum on the proliferation and osteogenic differentiation of bone marrow stromal cells

The present study aimed to investigate the effect of kidney-reinforcing and marrow-beneficial traditional Chinese medicine (TCM)-intervened (KRMBTI)-serum on the proliferation and osteogenic differentiation of bone marrow stromal cells (BMSCs) in rats. Rat BMSCs were isolated and cultured in vitro with various concentrations of serum obtained from rats at different time-points following treatment with low, medium and high doses of KRMBT. The alkaline phosphatase (ALP) activity and proliferation of the BMCSs was assessed to determine the optimal serum sampling time-point and serum concentration. Transforming growth factor (TGF)-β1 expression of the BMSCs was detected using enzyme-linked immunosorbent assay (ELISA), and hepcidin mRNA expression in the rat livers was detected using reverse transcription polymerase chain reaction. The proliferation of BMCSs treated with serum obtained l h after dosing was observed to be significantly higher than that for BMCSs treated with serum obtained at the four other time-points (P<0.05). Furthermore, the proliferation following treatment with 25% KRMBTI-serum was significantly higher than that for the other KRMBTI-serum concentrations (P<0.01). For a 25% concentration of the serum collected at l h, the proliferation in the high- and low-dose KRMBTI-serum groups was significantly higher than that of the medium-dose and control groups (P<0.01) and no statistical significance was observed between the high- and low-dose groups. In the osteogenic differentiation process of the high-dose group, the ALP activity at every time-point was significantly higher than that of the low-dose group and the peak value of the former was achieved at concentrations between 20 and 30%. KRMBTI-serum was shown to promote the expression of TGF-β1. Furthermore, hepcidin was observed to be expressed at significantly higher levels in the high-dose group than in the control group, and hepcidin expression was significantly higher after 10 weeks compared with that after five weeks. These findings suggest that KRMBTI-serum increases TGF-β1 and hepcidin expression levels, which may be the mechanism underlying the promotion of osteogenic differentiation induced by KRMBTI-serum in BMSCs.

Partial agonist, telmisartan, maintains PPARγ serine 112 phosphorylation, and does not affect osteoblast differentiation and bone mass

Peroxisome proliferator activated receptor gamma (PPARγ) controls both glucose metabolism and an allocation of marrow mesenchymal stem cells (MSCs) toward osteoblast and adipocyte lineages. Its activity is determined by interaction with a ligand which directs posttranscriptional modifications of PPARγ protein including dephosphorylation of Ser112 and Ser273, which results in acquiring of pro-adipocytic and insulin-sensitizing activities, respectively. PPARγ full agonist TZD rosiglitazone (ROSI) decreases phosphorylation of both Ser112 and Ser273 and its prolonged use causes bone loss in part due to diversion of MSCs differentiation from osteoblastic toward adipocytic lineage. Telmisartan (TEL), an anti-hypertensive drug from the class of angiotensin receptor blockers, also acts as a partial PPARγ agonist with insulin-sensitizing and a weak pro-adipocytic activity. TEL decreased ^S273pPPARγ and did not affect ^S112pPPARγ levels in a model of marrow MSC differentiation, U-33/γ2 cells. In contrast to ROSI, TEL did not affect osteoblast phenotype and actively blocked ROSI-induced anti-osteoblastic activity and dephosphorylation of ^S112pPPARγ. The effect of TEL on bone was tested side-by-side with ROSI. In contrast to ROSI, TEL administration did not affect bone mass and bone biomechanical properties measured by micro-indentation method and did not induce fat accumulation in bone, and it partially protected from ROSI-induced bone loss. In addition, TEL induced “browning” of epididymal white adipose tissue marked by increased expression of UCP1, FoxC2, Wnt10b and IGFBP2 and increased overall energy expenditure. These studies point to the complexity of mechanisms by which PPARγ acquires anti-osteoblastic and pro-adipocytic activities and suggest an importance of Ser112 phosphorylation status as being a part of the mechanism regulating this process. These studies showed that TEL acts as a full PPARγ agonist for insulin-sensitizing activity and as a partial agonist/partial antagonist for pro-adipocytic and anti-osteoblastic activities. They also suggest a relationship between PPARγ fat “browning” activity and a lack of anti-osteoblastic activity.

Breast cancer and osteoporosis

PURPOSE OF REVIEW

Over the past few years, a number of studies have examined the relationship between breast cancer and osteoporosis, the effect of breast cancer treatment on bone health, and the effect of osteoporosis therapies on aromatase inhibitor-induced bone loss and breast cancer recurrence. New guidelines have been released on the prevention of osteoporotic fractures in women with breast cancer who are on aromatase inhibitors for adjuvant therapy.

RECENT FINDINGS

Despite common factors linking high bone mineral density and increased risk of breast cancer, women with breast cancer are not protected from osteoporosis or osteoporotic fractures. Recent data suggest that aromatase inhibitors have a detrimental effect on bone mineral density and can increase the risk of fractures. Bisphosphonate therapy not only preserves aromatase inhibitor-induced bone loss, but may also improve disease-free survival and decrease risk of death in select women with breast cancer (i.e., postmenopausal women).

SUMMARY

Osteoporosis and breast cancer are common in women, especially in postmenopausal women. Current guidelines suggest that we need to pay special attention to those on aromatase inhibitors to prevent adverse bone outcomes.

Both baseline clinical factors and genetic polymorphisms influence the development of severe functional status in ankylosing spondylitis

Functional severity in ankylosing spondylitis (AS) patients is variable and difficult to predict early. The aim of our study was to assess whether a combination of baseline clinical factors and genetic markers may predict the development of severe functional status in AS. We performed a cross-sectional association study on AS patients included in the Spanish National Registry of Spondyloarthropathies—REGISPONSER. Bath Ankylosing Spondylitis Functional Index (BASFI) was standardized by adjusting for disease duration since the first symptoms (BASFI/t). We considered as severe functional status the values of BASFI/t in the top of the 60th (p60), 65th (p65), 70th (p70), and 75th (p75) percentile. We selected 384 single nucleotide polymorphisms (SNPs) distributed in 190 genes to be analyzed. The study cohort included 456 patients with mean age 50.8(±10.5) years and with mean disease duration since first symptoms 24.7 (±10.1) years. Older age at disease onset and neck pain at baseline showed statistical significant association with severe BASFI/t. Polymorphisms associated in the allele frequencies test with severe BASFI/t in all classifications were: rs2542151 (p60 [P = .04], p65 [P = .04], p70 [P = .001] and p75 [P = .001]) and rs2254441 (p60 [P = .004], p65 [P = .02], p70 [P = .01] and p75 [P<.001]).. Genotype association, after adjustment for covariates, found an association in three of the four patients' classifications for rs2542151 and in two of the classifications for rs2254441.Forward logistic regression did not identify any model with a good predictive power for severe functional development.

In our study we identified clinical factors and 24 polymorphisms associated with development of severe functional status in AS patients. Validation of these results in other cohorts is required.

Follistatin as a potent regulator of bone metabolism

Follistatin is a monomeric glycoprotein, distributed in a wide range of tissues. Recent work has demonstrated that this protein is a pluripotential molecule that has no structural similarity but is functionally associated with members of the transforming growth factor (TGF)-β superfamily, which indicates its wide range of action. Members of the TGF-β superfamily, especially activins and bone morphogenetic proteins are involved in bone metabolism. They play an important role in bone physiology, influencing bone growth, turnover, bone formation and cartilage induction. As follistatin is considered to be the antagonist of the TGF-β superfamily members, it plays an important role in bone metabolism and development.

TGF-beta3 and cancer: a review

With the development of growth factors and growth factor modulators as therapeutics for a range of disorders, it is prudent to consider whether modulating the growth factor profile in a tissue can influence tumour initiation or progression. As recombinant human TGF-beta3 (avotermin) is being developed for the improvement of scarring in the skin it is important to understand the role, if any, of this cytokine in tumour progression. Elevated levels of TGF-beta3 expression detected in late-stage tumours have linked this cytokine with tumourigenesis, although functional data to support a causative role are lacking. While it has proved tempting for researchers to interpret a 'correlation' as a 'cause' of disease, what has often been overlooked is the normal biological role of TGF-beta3 in processes that are often subverted in tumourigenesis. Clarifying the role of this cytokine is complicated by inappropriate extrapolation of the data relating to TGF-beta1 in tumourigenesis, despite marked differences in biology between the TGF-beta isoforms. Indeed, published studies have indicated that TGF-beta3 may actually play a protective role against tumourigenesis in a range of tissues including the skin, breast, oral and gastric mucosa. Based on currently available data it is reasonable to hypothesize that administration of acute low doses of exogenous TGF-beta3 is unlikely to influence tumour initiation or progression.

Chronic treatment with angiotensin AT1 receptor antagonists reduced serum but not bone TGF-beta1 levels in ovariectomized rats

Approximately 50% of hypertensive patients are postmenopausal women; therefore, any antihypertensive therapy must not adversely affect bone loss in this population. Recently, however, concern has been raised that use of angiotensin AT1 receptor antagonists may increase the tendency to develop postmenopausal osteoporosis by decreasing transforming growth factor-beta1 (TGF-beta1), which has been implicated in bone mass maintenance. In the present study, we selected telmisartan and valsartan as representatives of angiotensin AT1 receptor antagonists and used ovariectomized (OVX) rats as a model of human postmenopausal osteoporosis. After 3 months treatment with telmisartan (5 mg/kg daily) or valsartan (10 mg/kg daily), OVX rats showed no signs of adverse effects on bone mineral density of the lumbar vertebrae (L1-L5) or the total femur, nor did treatment affect serum levels of osteocalcin and osteoclast-derived tartrate-resistant acid phosphatase (TRACP-5b). Bone TGF-beta1 content remained unchanged, although treatment with telmisartan and valsartan significantly reduced serum TGF-beta1 levels (p < 0.05). In conclusion, chronic treatment with angiotensin AT1 receptor antagonists reduced serum but not bone TGF-beta1 levels and did not accelerate ovariectomy-induced bone loss in rats.

Relationship between age-related serum concentrations of TGF-beta1 and TGF-beta2 and those of osteoprotegerin and leptin in native Chinese women

BACKGROUND

Transforming growth factor-beta 1 (TGF-beta1), TGF-beta2, osteoprotegerin (OPG), and leptin are important cytokines in the regulation of bone remodeling. We investigated the relationship of TGF-beta1 and TGF-beta2 concentrations with those of OPG and leptin in Chinese females.

METHODS

The serum concentrations of TGF-beta1, TGF-beta2, OPG, and leptin were measured by ELISA in 459 healthy Chinese females aged 25-80 y.

RESULTS

The mean values (+/-SD) of the serum concentrations of TGF-beta1, TGF-beta2, OPG, and leptin in Chinese females were 29.7+/-1.69 microg/l, 13.7+/-3.86 microg/l, 3.81+/-1.96 pmol/l, and 10.5+/-2.01 microg/l, respectively. Further, the serum TGF-beta1 concentrations of postmenopausal women were significantly lower than those of perimenopausal and premenopausal women (24.3+/-1.59 vs 33.4+/-1.69 and 37.6+/-1.64, respectively), while the TGF-beta2 concentrations of postmenopausal women were significantly higher than those of perimenopausal and premenopausal women (14.6+/-3.91 vs 13.5+/-3.93 and 11.7+/-2.68, respectively). The serum TGF-beta1 concentration was found to be significantly negatively correlated with age (r=-0.335, P=0.000) and the TGF-beta2 concentration, to be significantly positively correlated with age (r=0.230, P=0.000). The TGF-beta1 concentration was found to be significantly negatively correlated with both TGF-beta2 (r=-0.261, P=0.000) and OPG (r=-0.313, P=0.000) concentrations; a significantly positive correlation was found between the TGF-beta1 and leptin concentrations (r=0.164, P=0.000) and between TGF-beta2 and OPG concentrations (r=0.432, P=0.000).

CONCLUSION

These results provide age-related reference values of TGF-beta1 and TGF-beta2 in Chinese adult women, and reveal the relationships between these cytokines.

Correlates of bone mineral density among postmenopausal women of African Caribbean ancestry: Tobago women's health study

Population dynamics predict a drastic growth in the number of older minority women, and resultant increases in the number of fractures. Low bone mineral density (BMD) is an important risk factor for fracture. Many studies have identified the lifestyle and health-related factors that correlate with BMD in Whites. Few studies have focused on non-Whites. The objective of the current analyses is to examine the lifestyle, anthropometric and health-related factors that are correlated with BMD in a population based cohort of Caribbean women of West African ancestry. We enrolled 340 postmenopausal women residing on the Caribbean Island of Tobago. Participants completed a questionnaire and had anthropometric measures taken. Hip BMD was measured by DXA. We estimated volumetric BMD by calculating bone mineral apparent density (BMAD). BMD was >10% and >25% higher across all age groups in Tobagonian women compared to US non-Hispanic Black and White women, respectively. In multiple linear regression models, 35-36% of the variability in femoral neck and total hip BMD respectively was predicted. Each 16-kg (one standard deviation (SD)) increase in weight was associated with 5% higher BMD; and weight explained over 10% of the variability of BMD. Each 8-year (1 SD) increase in age was associated with 5% lower BMD. Current use of both thiazide diuretics and oral hypoglycemic medication were associated with 4-5% higher BMD. For femoral neck BMAD, 26% of the variability was explained by a multiple linear regression model. Current statin use was associated with 5% higher BMAD and a history of breast feeding or coronary heart disease was associated with 1-1.5% of higher BMAD. In conclusion, African Caribbean women have the highest BMD on a population level reported to date for women. This may reflect low European admixture. Correlates of BMD among Caribbean women of West African ancestry were similar to those reported for U.S. Black and White women.

New insights into breast cancer genetics and impact on patient management

OPINION STATEMENT

The combined observation that 20-30% of all patients with breast cancer have a family history of the disease and the results from twin studies showing that 25% of breast cancer cases are heritable, indicate that this malignancy is one of the most commonly inherited cancers. Discovery of the BRCA1 and BRCA2 genes more than a decade ago has had a tremendous impact on patient care allowing for early detection and prevention of breast cancer. However, deleterious mutations within the BRCA1 and BRCA2 genes cause at most 3-8% of all breast cancer cases. New data indicate that genomic rearrangements within the same genes may occasionally identify additional carriers of nonfunctional BRCA1 and BRCA2 genes. Such genomic rearrangements are missed by conventional sequencing. The remainder of the unexplained familial risk is presumably due to other yet unidentified high penetrance genes, but polygenic mechanisms and high frequency low penetrance tumor susceptibility genes are likely to account for a greater proportion of familial breast cancers. In this regard, there is growing evidence that a common variant of the type I TGF-ss receptor, TGFBR1*6A, may account for approximately 5% of all breast cancer cases, a fraction similar to that attributable to BRCA1 and BRCA2. Such genes may also modify the penetrance of the BRCA1 and BRCA2 genes. In the next decade, screening for combinations of high and low penetrance genes will likely permit the identification of a large fraction of inherited breast cancer cases and will further reduce the burden of familial breast cancer.

Low transforming growth factor-beta1 serum levels in idiopathic male osteoporosis

INTRODUCTION

Although the etiology of osteoporosis is different between men and women, the underlying pathophysiological mechanism is similar, namely an absolute or relative increase in bone resorption, leading to progressive bone loss. Transforming growth factor (TGF)-beta1 is a growth factor in human bone, which is produced by osteoblasts, and which has various effects on osteoclasts and osteoblasts. The aim of our study was to determine serum TGF-beta1 levels in male patients with idiopathic osteoporosis.

METHODS

Twenty five males with idiopathic osteoporosis and 25 age-matched controls were studied. Osteoporosis was defined by a T score of <-2.5 in the lumbar spine or at the femoral neck. We measured levels of TGF-beta1, estradiol, total and bioactive testosterone. Various markers of bone remodeling were also measured.

RESULTS

TGF-beta1 was significantly lower in osteoporotic patients than in controls (3.706 ng/dl, 25-75 percentiles: 2.81-5.33 vs 8.659 ng/dl, 25-75 percentiles: 4.837-11.835; p=0.000). Moreover, TGF-beta1 levels were positively correlated with bone mineral density (BMD) at the femoral neck (r=0.439, p=0.028), and at the lumbar spine (r=0.41, p=0.042). No correlation was found between serum estradiol, testosterone and TGF-beta1 levels.

DISCUSSION

Serum TGF-beta1 levels are depressed in osteoporotic men and are positively correlated with hip and spine BMD. The results of our study suggest that TGF-beta1 may play a role in the pathogenesis of idiopathic male osteoporosis.

Determination of oxidative stress status and concentration of TGF-beta 1 in the blood and saliva of osteoporotic subjects

Preliminary reports indicate the influence of oxidative stress and interleukins, particularly TGF-beta1, in maintenance of bone mass. This study was designed to determine any possible variations of cellular lipid peroxidation, the total antioxidant power, and concentration of TGF-beta1 in blood and saliva of osteoporotic subjects in comparison to healthy people. Blood and saliva samples of 22 osteoporotic women and 22 age-matched healthy women were collected. Samples were analyzed for thiobarbituric acid-reactive substances (TBARS) as a marker of lipid peroxidation, ferric reducing ability (total antioxidant power, TAP), and concentration of TGF-beta1. The blood and saliva TAP (mean +/- SD) of osteoporotic subjects was significantly lower than that of healthy controls (606.65 +/- 119.13 vs. 665.64 +/- 63.73 mmol/L and 560.43 +/- 84.70 vs. 612.05 +/- 81.5, respectively). Blood and saliva TBARS (mean +/- SD) of osteoporotic subjects were significantly higher than those of healthy controls (0.30 +/- 0.04 vs. 0.26 +/- 0.04 and 0.23 +/- 0.03 vs. 0.16 +/- 0.04 micromol/L, respectively). Concentrations of TGF-beta1 (mean +/- SD) in plasma and saliva of osteoporotic subjects were not different in comparison to healthy subjects. Results indicate that persons with osteoporosis have an increased oxidative stress that is not accompanied by changes in TGF-beta1 levels. Use of supplementary antioxidants in osteoporotic patients may be helpful.

Increased Levels of Transforming Growth Factor-Beta1 and -Beta2 in the Aqueous Humor of Patients With Neovascular Glaucoma

BACKGROUND AND OBJECTIVE

To measure the concentrations of transforming growth factor-betal and beta2 (TGF-beta1 and TGF-beta2) in the aqueous humor of patients with neovascular glaucoma (NVG).

PATIENTS AND METHODS

Patients were divided into four groups: NVG secondary to central retinal vein occlusion (group 1), NVG secondary to proliferative diabetic retinopathy (group 2), central retinal vein occlusion without rubeosis (group 3), and senile cataract (group 4). The total TGF-beta 1 and TGF-beta2 concentrations in the aqueous humor of the four groups were measured by enzyme linked immunosorbent assay.

RESULTS

The mean concentrations of total TGF-betal were 600.7 +/-436.7 microg/mL in group 1, 802.0 +/-359.5 pg/mL in group 2, and undetectable in groups 3 and group 4 (P < .05). The mean concentrations of total TGF-beta2 were 6,307.9+/- 2,206.2 microg/mL in group 1, 5,908.0+/-2,033.2 microg/mL in group 2, 899.7+/- 425.6 microg/mL in group 3, and 385.7 +/-89.9 microg/mL in group 4. The total TGF-betal and TGF-beta2 concentrations in groups 1 and 2 were significantly higher than those in groups 3 and 4, whereas the total TGF-beta2 concentration in group 3 was significantly higher than that in group 4 (P < .05). There was no significant difference in the TGF-betal or TGF-beta2 concentrations between groups 1 and 2 (P> .05).

CONCLUSIONS

The abnormally high concentrations of TGF-betal and TGF-beta2 in the aqueous humor of patients with NVG may explain some aspects of the pathogenesis of NVG and the high failure rate of filtering operations in NVG.

Single nucleotide polymorphisms of the TGFB1 gene and lung cancer risk in a Korean population

The present study was conducted to investigate the association between single nucleotide polymorphisms (SNPs) of the transforming growth factor-beta 1 (TGFB1) gene and susceptibility to lung cancer and the clinical effect of the SNPs on lung cancer progression in a Korean population. Two polymorphisms in the promoter region of the TGFB1 (T-1572C, C-509T), and one SNP in codon 10 (T+869C) were determined using a SNaPshot primer extension assay in 194 Korean lung cancer patients and 283 normal controls. The polymorphic allele frequencies of A-1572G, C-509T, and T+869C were similar among lung cancer patients (0.52, 0.47, and 0.47, respectively) and controls (0.54, 0.46, and 0.44, respectively). When the data was stratified for smoking history, patients who smoked heavily and had heterozygous C-509T and T+869C genotypes showed an increased lung cancer risk (odds ratio OR = 3.77, confidence interval 95% CI = 1.25-11.30, P = 0.017; OR = 3.61, 95% CI = 1.21-10.74, P = 0.021 for each), after adjustment for age and sex. When heterozygous and homozygous variants for each SNPs were analyzed together, patients who were smokers and had variant genotypes also showed increased risk compared to the reference group. Further analyses to test the effect of the SNPs on the clinical parameters did not reveal an association of each polymorphic allele to the tumor stage or response to treatment. In addition, DNA fragments containing polymorphic genotype of the promoter region (-509T) showed increased transcriptional activity in luciferase assays using non-small cell lung cancer cell lines. In conclusion, this study suggests that heavy smokers in this Korean population who have specific polymorphic variants, which have been associated with increased transcriptional activity of TGFB1, might be more vulnerable to lung cancer.

A pattern of anti-carbohydrate antibody responses present in patients with advanced atherosclerosis

We have previously shown that an antibody pool present in normal human serum binds cytokine receptors in vitro and may therefore interfere with assays that capture cytokines using their receptors. Here we show that this antibody pool is the same as the natural antibody termed anti-gal, that binds to the alpha-galactosyl carbohydrate epitope (alpha-gal) and which is the predominant obstacle to xenotransplantation. We report that there are high levels of IgD anti alpha-gal in most volunteers, in addition to the IgG2, IgA and IgM immunoglobulin isotypes against alpha-gal previously described. To determine if anti-gal may interfere with assays that depend on capture of cytokine with its receptor, we measured levels of several anti-carbohydrate antibodies in a cohort of patients with advanced atherosclerosis that had previously been used to measure levels of active TGF-beta using such an assay. For many isotype / carbohydrate combinations, there is a large and significant difference between the levels of anti-carbohydrate antibodies in patients with atherosclerosis and controls, after adjustment for age, sex and blood group. These results are similar to the previous data obtained for active TGF-beta, and therefore we cannot discount the possibility that anti-gal contributed to the previous data. Following further adjustment for several risk factors associated with cardiovascular disease, several anti-carbohydrate antibodies were still significantly different between patients and controls. Therefore, anti-carbohydrate antibodies may represent a new class of risk factors that may be associated with presence of advanced atherosclerosis, although larger studies will be required to confirm this hypothesis.

Estrogen prevents bone loss through transforming growth factor beta signaling in T cells

Estrogen (E) deficiency leads to an expansion of the pool of tumor necrosis factor (TNF)-producing T cells through an IFN-gamma-dependent pathway that results in increased levels of the osteoclastogenic cytokine TNF in the bone marrow. Disregulated IFN-gamma production is instrumental for the bone loss induced by ovariectomy (ovx), but the responsible mechanism is unknown. We now show that mice with T cell-specific blockade of type beta transforming growth factor (TGFbeta) signaling are completely insensitive to the bone-sparing effect of E. This phenotype results from a failure of E to repress IFN-gamma production, which, in turn, leads to increased T cell activation and T cell TNF production. Furthermore, ovx blunts TGFbeta levels in the bone marrow, and overexpression of TGFbeta in vivo prevents ovx-induced bone loss. These findings demonstrate that E prevents bone loss through a TGFbeta-dependent mechanism, and that TGFbeta signaling in T cells preserves bone homeostasis by blunting T cell activation. Thus, stimulation of TGFbeta production in the bone marrow is a critical "upstream" mechanism by which E prevents bone loss, and enhancement of TGFbeta levels in vivo may constitute a previously undescribed therapeutic approach for preventing bone loss.

Transforming growth factor-beta induces osteoclast formation in the absence of RANKL

Transforming growth factor beta (TGFbeta) is a multifunctional growth factor that is produced by many cells in bone and is abundant in the bone matrix. TGFbeta is known to regulate RANKL-induced osteoclast formation and bone resorbing activity. In this study we sought to determine whether TGFbeta could directly induce osteoclast formation by a RANKL-independent mechanism. We found that the addition of TGFbeta to cultures of human monocytes and RAW 264.7 cells (in the presence of M-CSF and the absence of RANKL, TNFalpha or IL-6/IL-11) was sufficient to induce the formation of TRAP+ and VNR+ cells, which formed actin rings and were capable of extensive lacunar resorption. The addition of osteoprotegerin or antibodies to TNFalpha and its receptors, as well as antibodies to gp130, did not inhibit lacunar resorption, indicating that TGFbeta did not act by stimulating RANKL, TNF or IL-6 production by monocytes. TGFbeta-induced osteoclast formation was qualitatively different from that induced by RANKL with numerous TRAP+/VNR+ mononuclear and small multinucleated cells being formed; these cells produced many small resorption lacunae. Our results indicate that TGFbeta, which is abundant in the bone matrix, can, in the presence of M-CSF, directly induce mononuclear phagocyte osteoclast precursors to differentiate into osteoclastic cells capable of lacunar resorption.

Transforming growth factor beta-3 crystals as reservoirs for slow release of active TGF-beta3

Transforming growth factor betas (TGF-betas) play critical roles in many diseased states and injury repair processes. Exogenous delivery of TGF-beta may thus have therapeutic applications. Here, crystals of TGF-beta3 (TGF-beta3) are being evaluated as protected reservoirs for sustained local release. A sensitive Mv1Lu cell growth inhibition assay established that in vitro, active TGF-beta3 can be delivered from physically stable crystals. Non-sink release experiments revealed that crystal solubility at pH 7.4 was higher in cell culture medium (2.7+/-0.1 microg/ml) than in saline buffers (approximately 1-1.5 microg/ml, P<0.05). Addition of serum induced a five-fold delay in equilibration of soluble-crystal TGF-beta3. Semi-sink experiments cumulated in higher TGF-beta3 release than under non-sink conditions; the observed steady states correlated with crystal solubility and the frequency of buffer exchange. Release of TGF-beta3 from crystals was also strongly dependent on solubility changes as affected by pH. At neutral pH the solubilities were the lowest, and increased with both higher and lower pH. The results indicate that TGF-beta3 crystals may have promising features for local pH-triggered sustained-release applications.

Bone mass and breast cancer risk in older women: differences by stage at diagnosis

BACKGROUND

Older women with low bone mineral density (BMD) have a decreased incidence of breast cancer. It is not known whether this association is confined to early-stage, slow-growing tumors.

METHODS

We prospectively studied 8905 women who were 65 years of age or older during the period from 1986 through 1988 and had no history of breast cancer. At study entry, we used single-photon absorptiometry to measure each woman's BMD at three skeletal sites: the wrist, forearm, and heel. The women were followed for a mean of 6.5 years for the occurrence of breast cancer. All statistical tests were two-sided.

RESULTS

During 57 516 person-years of follow-up, 315 women developed primary invasive or in situ breast cancer. Multivariate analyses that adjusted for age, obesity, and other covariates revealed that the risk of breast cancer for women in the highest quartile of BMD for all three skeletal sites was 2.7 (95% confidence interval [CI] = 1.4 to 5.3) times greater than that for women in the lowest quartile at all three skeletal sites. The magnitude of increased risk associated with high BMD differed by the stage of disease at diagnosis and was greater for more advanced tumors (relative risk [RR] for TNM [i.e., tumor-lymph node-metastasis] stage II or higher tumors = 5.6; 95% CI = 1.2 to 27.4) than for early-stage disease (RR for in situ/TNM stage I tumors = 2.2; 95% CI = 1.0 to 4.8).

CONCLUSIONS

Elderly women with high BMD have an increased risk of breast cancer, especially advanced cancer, compared with women with low BMD. These findings suggest an association between osteoporosis and invasive breast cancer, two of the most prevalent conditions affecting an older woman's health.

Mineral, amino acid, and hormonal composition of chicken eggshell powder and the evaluation of its use in human nutrition

Chicken eggshell powder (ESP) might be an attractive source of Ca for human nutrition. To study its nutritional value, we analyzed minerals, amino acids, and hormones in commercially available Slovakian ESP. The mineral composition was compared with three Dutch ESP samples that differed in feed and housing, a Japanese ESP, refined CaCO3, and an oyster shell supplement. Chicken eggshell powder contains high levels of Ca (mean +/- SD/g EPS: 401+/-7.2 mg) and Sr (372+/-161 microg) when compared with recommended or estimated daily intakes for humans 51 to 70 yr of age. Levels of potentially toxic Pb, Al, Cd, and Hg were very low as were levels of V, B, Fe, Zn, P, Mg, N, F, Se, Cu, and Cr. Large differences in the levels of F, Se, Cu, Cr, and Sr in the Dutch and Slovakian ESP indicated a strong influence of feed and environment. The small protein fraction of ESP contains high levels of Gly and Arg. Furthermore, small amounts of transforming growth factor-beta1 (0.75 to 7.28 ng/g ESP), calcitonin (10 to 25 ng/g ESP), and progesterone (0.30 to 0.33 ng/g ESP) were detected. Estradiol-17beta and calcitriol were below the detection limit of the methods used. Compared with ESP, refined CaCO3 was found to contain increased levels of Cd, and the oyster shell supplement showed increased levels of Al and Cd. Therefore, ESP seems to have a beneficial composition with about 39% of elemental Ca, relevant amounts of Sr, and low levels of Al, Pb, Cd and Hg. It may be used as a Ca source in human nutrition.

Endogenous production of TGF-beta is essential for osteoclastogenesis induced by a combination of receptor activator of NF-kappa B ligand and macrophage-colony-stimulating factor

Differentiation of osteoclasts, the cells primarily responsible for bone resorption, is controlled by a variety of osteotropic hormones and cytokines. Of these factors, receptor activator of NF-kappaB (RANK) ligand (RANKL) has been recently cloned as an essential inducer of osteoclastogenesis in the presence of M-CSF. Here, we isolated a stroma-free population of monocyte/macrophage (M/Mphi)-like hemopoietic cells from mouse unfractionated bone cells that were capable of differentiating into mature osteoclasts by treatment with soluble RANKL (sRANKL) and M-CSF. However, the efficiency of osteoclast formation was low, suggesting the requirement for additional factors. The isolated M/Mphi-like hemopoietic cells expressed TGF-beta and type I and II receptors of TGF-beta. Therefore, we examined the effect of TGF-beta on osteoclastogenesis. TGF-beta with a combination of sRANKL and M-CSF promoted the differentiation of nearly all M/Mphi-like hemopoietic cells into cells of the osteoclast lineage. Neutralizing anti-TGF-beta Ab abrogated the osteoclast generation. These TGF-beta effects were also observed in cultures of unfractionated bone cells, and anti-TGF-beta blocked the stimulatory effect of 1, 25-dihydroxyvitamin D(3). Translocation of NF-kappaB into nuclei induced by sRANKL in TGF-beta-pretreated M/Mphi-like hemopoietic cells was greater than that in untreated cells, whereas TGF-beta did not up-regulate the expression of RANK, the receptor of RANKL. Our findings suggest that TGF-beta is an essential autocrine factor for osteoclastogenesis.

TGF-beta in blood: a complex problem

The cytokine transforming growth factor-beta (TGF-beta) was initially purified from human platelets, a rich source of this protein. In addition to platelets, TGF-beta1 is also found in other blood fractions, including plasma and the circulating leukocytes. However, more than 15 years after the initial isolation of TGF-beta1, there remains no consensus on how much TGF-beta1 is present in normal human plasma. Here we review the difficulties associated with measuring TGF-beta concentrations in complex biological fluids, and discuss the current state of knowledge on the distribution of TGF-beta isoforms in various blood fractions as well as the nature of the TGF-beta-containing protein complexes.