Interrogating Estrogen Signaling Pathways in Human ER-Positive Breast Cancer Cells Forming Bone Metastases in Mice

Breast cancer bone metastases (BMET) are incurable, primarily osteolytic, and occur most commonly in estrogen receptor-α positive (ER+) breast cancer. ER+ human breast cancer BMET modeling in mice has demonstrated an estrogen (E2)-dependent increase in tumor-associated osteolysis and bone-resorbing osteoclasts, independent of estrogenic effects on tumor proliferation or bone turnover, suggesting a possible mechanistic link between tumoral ERα-driven osteolysis and ER+ bone progression. To explore this question, inducible secretion of the osteolytic factor, parathyroid hormone-related protein (PTHrP), was utilized as an in vitro screening bioassay to query the osteolytic potential of estrogen receptor- and signaling pathway-specific ligands in BMET-forming ER+ human breast cancer cells expressing ERα, ERß, and G protein-coupled ER. After identifying genomic ERα signaling, also responsibility for estrogen's proliferative effects, as necessary and sufficient for osteolytic PTHrP secretion, in vivo effects of a genomic-only ER agonist, estetrol (E4), on osteolytic ER+ BMET progression were examined. Surprisingly, while pharmacologic effects of E4 on estrogen-dependent tissues, including bone, were evident, E4 did not support osteolytic BMET progression (vs robust E2 effects), suggesting an important role for nongenomic ER signaling in ER+ metastatic progression at this site. Because bone effects of E4 did not completely recapitulate those of E2, the relative importance of nongenomic ER signaling in tumor vs bone cannot be ascertained here. Nonetheless, these intriguing findings suggest that targeted manipulation of estrogen signaling to mitigate ER+ metastatic progression in bone may require a nuanced approach, considering genomic and nongenomic effects of ER signaling on both sides of the tumor/bone interface.

Nonequilibrium thermodynamics and mitochondrial protein content predict insulin sensitivity and fuel selection during exercise in human skeletal muscle

Introduction: Many investigators have attempted to define the molecular nature of changes responsible for insulin resistance in muscle, but a molecular approach may not consider the overall physiological context of muscle. Because the energetic state of ATP (ΔGATP) could affect the rate of insulin-stimulated, energy-consuming processes, the present study was undertaken to determine whether the thermodynamic state of skeletal muscle can partially explain insulin sensitivity and fuel selection independently of molecular changes. Methods: 31P-MRS was used with glucose clamps, exercise studies, muscle biopsies and proteomics to measure insulin sensitivity, thermodynamic variables, mitochondrial protein content, and aerobic capacity in 16 volunteers. Results: After showing calibrated 31P-MRS measurements conformed to a linear electrical circuit model of muscle nonequilibrium thermodynamics, we used these measurements in multiple stepwise regression against rates of insulin-stimulated glucose disposal and fuel oxidation. Multiple linear regression analyses showed 53% of the variance in insulin sensitivity was explained by 1) VO2max (p = 0.001) and the 2) slope of the relationship of ΔGATP with the rate of oxidative phosphorylation (p = 0.007). This slope represents conductance in the linear model (functional content of mitochondria). Mitochondrial protein content from proteomics was an independent predictor of fractional fat oxidation during mild exercise (R2 = 0.55, p = 0.001). Conclusion: Higher mitochondrial functional content is related to the ability of skeletal muscle to maintain a greater ΔGATP, which may lead to faster rates of insulin-stimulated processes. Mitochondrial protein content per se can explain fractional fat oxidation during mild exercise.

Curcumin Supplementation and Human Disease: A Scoping Review of Clinical Trials

Medicinal properties of turmeric (Curcuma longa L.), a plant used for centuries as an anti-inflammatory, are attributed to its polyphenolic curcuminoids, where curcumin predominates. Although "curcumin" supplements are a top-selling botanical with promising pre-clinical effects, questions remain regarding biological activity in humans. To address this, a scoping review was conducted to assess human clinical trials reporting oral curcumin effects on disease outcomes. Eight databases were searched using established guidelines, yielding 389 citations (from 9528 initial) that met inclusion criteria. Half focused on obesity-associated metabolic disorders (29%) or musculoskeletal disorders (17%), where inflammation is a key driver, and beneficial effects on clinical outcomes and/or biomarkers were reported for most citations (75%) in studies that were primarily double-blind, randomized, and placebo-controlled trials (77%, D-RCT). Citations for the next most studied disease categories (neurocognitive [11%] or gastrointestinal disorders [10%], or cancer [9%]), were far fewer in number and yielded mixed results depending on study quality and condition studied. Although additional research is needed, including systematic evaluation of diverse curcumin formulations and doses in larger D-RCT studies, the preponderance of current evidence for several highly studied diseases (e.g., metabolic syndrome, osteoarthritis), which are also clinically common, are suggestive of clinical benefits.

Fuel Selection in Skeletal Muscle Exercising at Low Intensity; Reliance on Carbohydrate in Very Sedentary Individuals

Background: Resting skeletal muscle in insulin resistance prefers to oxidize carbohydrate rather than lipid, exhibiting metabolic inflexibility. Although this is established in resting muscle, complexities involved in directly measuring fuel oxidation using indirect calorimetry across a muscle bed have limited studies of this phenomenon in working skeletal muscle. During mild exercise and at rest, whole-body indirect calorimetry imperfectly estimates muscle fuel oxidation. We provide evidence that a method termed "ΔRER" can reasonably estimate fuel oxidation in skeletal muscle activated by exercise. Methods: Completely sedentary volunteers (n = 20, age 31 ± 2 years, V̇O2peak 24.4 ± 1.5 mL O2 per min/kg) underwent glucose clamps to determine insulin sensitivity and graded exercise consisting of three periods of mild steady-state cycle ergometry (15, 30, 45 watts, or 10%, 20%, and 30% of maximum power) with measurements of whole-body gas exchange. ΔRER, the RER in working muscle, was calculated as (V̇CO2exercise -V̇CO2rest)/(V̇O2exercise - V̇O2rest), from which the fraction of fuel accounted for by lipid was estimated. Results: Lactate levels were low and stable during steady-state exercise. Muscle biopsies were used to estimate mitochondrial content. The rise of V̇O2 at onset of exercise followed a monoexponential function, with a time constant of 51 ± 7 sec, typical of skeletal muscle; the average O2 cost of work was about 12 mL O2/watt/min, representing a mechanical efficiency of about 24%. At work rates of 30 or 45 watts, active muscle relied predominantly on carbohydrate, independent of insulin sensitivity within this group of very sedentary volunteers. Conclusions: The fraction of muscle fuel oxidation from fat was predicted by power output (P < 0.001) and citrate synthase activity (P < 0.05), indicating that low mitochondrial content may be the main driver of fuel choice in sedentary people, independent of insulin sensitivity.

Association of ß-glucuronidase activity with menopausal status, ethnicity, adiposity, and inflammation in women

OBJECTIVES

Many dietary polyphenols with potential health-promoting benefits undergo hepatic conjugation and circulate as inactive glucuronides that can be cleaved by ß-glucuronidase to reform the bioactive aglycone. Although indirect evidence suggests estrogen may induce ß-glucuronidase, little is known about ß-glucuronidase regulation across women's reproductive lifespan. Correlates of serum ß-glucuronidase activity in healthy premenopausal versus postmenopausal women were therefore examined.

METHODS

ß-Glucuronidase activity and C-reactive protein (CRP) were assayed in stored serum from the Women's Breast and Bone Density Study, and dual-energy x-ray absorptiometry and anthropometry assessed body composition. Participants were premenopausal (n = 133) or postmenopausal (n = 89), and Hispanic (37%) or non-Hispanic White (63%). Multivariate linear regression models tested associations between ß-glucuronidase and menopausal status, ethnicity, CRP, and body composition metrics, overall and stratified by menopausal status.

RESULTS

Postmenopausal (vs premenopausal) women were older (60.4 ± 3.7 vs 44.8 ± 2.4 y) with a lower Hispanic ethnicity prevalence (27% vs 44%), and higher serum ß-glucuronidase activity (1.5 ± 0.8 vs 1.3 ± 0.5 U/L) and CRP (4.2 ± 4.4 vs 3.3 ± 4.7 mg/L). Adjusting for confounders, ß-glucuronidase was positively associated with Hispanic ethnicity, CRP, body mass index, and total fat mass (all, P < 0.01), but not menopausal status nor lean mass. Central adiposity measures were also positively associated with ß-glucuronidase with the same covariates.

CONCLUSIONS

ß-Glucuronidase enzyme activity, upon which polyphenol health-related benefits may depend, is not associated with menopausal status. Future studies are required to determine clinical significance and mechanisms driving ß-glucuronidase associations with ethnicity, inflammation, and adiposity in women.

Dietary Supplement Use in Women Diagnosed with Breast Cancer

BACKGROUND

Vitamins, minerals, and natural product (NP)-derived dietary supplements are commonly used among women with breast cancer, where interactions with treatments and the disease are possible, emphasizing the importance for health care providers to be aware of supplement use.

OBJECTIVES

The study aimed to investigate current vitamin/mineral (VM) and NP supplement use among those diagnosed with breast cancer, including usage based on tumor type or concurrent breast cancer treatments and primary information sources for specific supplements.

METHODS

Social media recruiting to complete an online questionnaire self-reporting current VM and NP use and breast cancer diagnosis and treatment information primarily attracted US participants. Analyses, including multivariate logistic regression, were performed on 1271 women who self-reported breast cancer diagnosis and completed the survey.

RESULTS

Most participants reported current VM (89.5%) and NP (67.7%) use, with 46.5% (VM) and 26.7% (NP) using at least 3 products concurrently. Top-reported (>15% prevalence) products were vitamin D, calcium, multivitamin, and vitamin C for VM and probiotics, turmeric, fish oil/omega-3 fatty acids, melatonin, and cannabis for NP. Overall, VM or NP use was higher among those with hormone receptor-positive tumors. Although overall NP use did not differ according to current breast cancer treatments, VM use was significantly less common among those currently undergoing chemotherapy or radiation, but higher with current endocrine therapy. Among current chemotherapy users, specific VM and NP supplements with possible adverse effects were still used by 23% of respondents. Medical providers were the primary information source for VM, whereas NP information sources were more varied.

CONCLUSIONS

Because women diagnosed with breast cancer commonly reported concurrent use of multiple VM and NP supplements, including those with known or underexplored risks (or benefits) in breast cancer, it is important for health care providers to inquire about and facilitate discussions regarding supplement use in this population.

Metabolically favorable adiposity and bone mineral density: a Mendelian randomization analysis

OBJECTIVE

This analysis assessed the putative causal association between genetically predicted percent body fat and areal bone mineral density (aBMD) and, more specifically, the association between genetically predicted metabolically "favorable adiposity" (MFA) and aBMD at clinically relevant bone sites.

METHODS

Mendelian randomization was used to assess the relationship of MFA and percent body fat with whole-body, lumbar spine, femoral neck, and forearm aBMD. Sex-stratified and age-stratified exploratory analyses were conducted.

RESULTS

In all MR analyses, genetically predicted MFA was inversely associated with aBMD for the whole body (β = -0.053, p = 0.0002), lumbar spine (β = -0.075; p = 0.0001), femoral neck (β = -0.045; p = 0.008), and forearm (β = -0.115; p = 0.001). This negative relationship was strongest in older individuals and did not differ by sex. The relationship between genetically predicted percent body fat and aBMD was nonsignificant across all Mendelian randomization analyses. Several loci that were associated at a genome-wide significance level (p < 5 × 10^-8 ) in opposite directions with body fat and aBMD measures were also identified.

CONCLUSIONS

This study did not support the hypothesis that MFA protects against low aBMD. Instead, it showed that MFA may result in lower aBMD. Further research is needed to understand how MFA affects aBMD and other components of bone health such as bone turnover, bone architecture, and osteoporotic fractures.

Serum Follicle-Stimulating Hormone and 5-Year Change in Adiposity in Healthy Postmenopausal Women

CONTEXT

Evidence from animal studies suggests that the gradual rise in follicle-stimulating hormone (FSH) during reproductive senescence may contribute to the change in adiposity distribution characteristic of menopause. The potential independent role the interrelationships of FSH and estradiol (E2) may play in postmenopausal adiposity changes are not well studied.

OBJECTIVE

Our objective was to evaluate the associations of FSH and dual x-ray absorptiometry (DXA)-derived adiposity measures, with consideration of estradiol and postmenopausal hormone therapy use.

METHODS

In a sample of 667 postmenopausal women from the Women's Health Initiative Buffalo OsteoPerio Ancillary Study, we studied the associations of serum FSH and E2 levels with dual x-ray absorptiometry (DXA)-derived adiposity measures via cross-sectional and longitudinal analyses (5-year follow-up).

RESULTS

In cross-sectional analyses, FSH levels were inversely associated with all measures of adiposity in models adjusted for age, years since menopause, smoking status, pack-years, and hormone therapy (HT) use; these associations were not influenced by adjustment for serum E2. In longitudinal analyses, the subset of women who discontinued HT over follow-up (n = 242) experienced the largest increase in FSH (+33.9 mIU/mL) and decrease in E2 (-44.3 pg/mL) and gains in all adiposity measures in unadjusted analyses. In adjusted analyses, an increase in FSH was associated with a gain in percentage of total body fat, total body fat mass, and subcutaneous adipose tissue (SAT).

CONCLUSION

While cross-sectional findings suggest that FSH is inversely associated with adiposity, our longitudinal findings suggest that greater increases in FSH were associated with greater increases in percentage of total body fat, total body fat mass, and SAT. Future studies are needed to provide additional insight into FSH-adiposity mechanisms in larger samples.

Cross-sectional associations between adipose tissue depots and areal bone mineral density in the UK Biobank imaging study

The relationship between obesity and osteoporosis is poorly understood. In this study, we assessed the association between adiposity and bone. The fat-bone relationship was dependent on sex, body mass index classification, and menopausal status. Results highlight the importance of accounting for direct measures of adiposity (beyond BMI) and menopause status.

INTRODUCTION

Assess the relationship between direct measures of adiposity (total body fat mass, visceral adipose tissue, and abdominal subcutaneous adipose tissue) with the whole body and clinically relevant bone sites of the lumbar spine, and femoral neck areal bone mineral density (aBMD) in men and women.

METHODS

This cross-sectional analysis was conducted utilizing de-identified data from the UK Biobank on participants (n = 3674) with available dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI) data. Sex-stratified multiple linear regression was used to assess the relationship between adiposity measures and aBMD outcomes, controlling for age, race, total body lean mass (DXA), height, BMI class, physical activity, smoking, menopausal status (women), and hormone use (women).

RESULTS

In men, significant interactions were observed between measures of adiposity and BMI on aBMD for the whole body and lumbar spine. Interactions indicated a positive relationship between adiposity and aBMD in men classified as normal weight, but an inverse relationship in men with elevated BMI. In women, significant interactions between adiposity measures and menopausal status were observed primarily for the whole body and femoral neck aBMD bone outcomes which indicated a negative relationship between adiposity and aBMD in premenopausal women, but a positive relationship in postmenopausal women.

CONCLUSION

Total body adiposity, abdominal subcutaneous adipose tissue, and visceral adipose tissue were all significantly associated with aBMD in both men and women. The strength and direction of association were dependent on sex, BMI classification, and menopausal status (women).

Curcumin Inhibition of TGFβ signaling in bone metastatic breast cancer cells and the possible role of oxidative metabolites

TGFβ signaling promotes progression of bone-metastatic (BMET) breast cancer (BCa) cells by driving tumor-associated osteolysis, a hallmark of BCa BMETs, thus allowing for tumor expansion within bone. Turmeric-derived bioactive curcumin, enriched in bone via local enzymatic deconjugation of inactive circulating curcumin-glucuronides, inhibits osteolysis and BMET progression in human xenograft BCa BMET models by blocking tumoral TGFβ signaling pathways mediating osteolysis. This is a unique antiosteolytic mechanism in contrast to current osteoclast-targeting therapeutics. Therefore, experiments were undertaken to elucidate the mechanism for curcumin inhibition of BCa TGFβ signaling and the application of this finding across multiple BCa cell lines forming TGFβ-dependent BMETs, including a possible role for bioactive curcumin metabolites in mediating these effects. Immunoblot analysis of TGFβ signaling proteins in bone tropic human (MDA-SA, MDA-1833, MDA-2287) and murine (4T1) BCa cells revealed uniform curcumin blockade of TGFβ-induced Smad activation due to down-regulation of plasma membrane associated TGFβR2 and cellular receptor Smad proteins that propagate Smad-mediated gene expression, resulting in downregulation of PTHrP expression, the osteolytic factor driving in vivo BMET progression. With the exception of early decreases in TGFβR2, inhibitory effects appeared to be mediated by oxidative metabolites of curcumin and involved inhibition of gene expression. Interestingly, while not contributing to changes in Smad-mediated TGFβ signaling, curcumin caused early activation of MAPK signaling in all cell lines, including JNK, an effect possibly involving interactions with TGFβR2 within lipid rafts. Treatment with curcumin or oxidizable analogs of curcumin may have clinical relevancy in the management of TGFβ-dependent BCa BMETs.

Perspective on Improving the Relevance, Rigor, and Reproducibility of Botanical Clinical Trials: Lessons Learned From Turmeric Trials

Plant-derived compounds, without doubt, can have significant medicinal effects since many notable drugs in use today, such as morphine or taxol, were first isolated from botanical sources. When an isolated and purified phytochemical is developed as a pharmaceutical, the uniformity and appropriate use of the product are well defined. Less clear are the benefits and best use of plant-based dietary supplements or other formulations since these products, unlike traditional drugs, are chemically complex and variable in composition, even if derived from a single plant source. This perspective will summarize key points-including the premise of ethnobotanical and preclinical evidence, pharmacokinetics, metabolism, and safety-inherent and unique to the study of botanical dietary supplements to be considered when planning or evaluating botanical clinical trials. Market forces and regulatory frameworks also affect clinical trial design since in the United States, for example, botanical dietary supplements cannot be marketed for disease treatment and submission of information on safety or efficacy is not required. Specific challenges are thus readily apparent both for consumers comparing available products for purchase, as well as for commercially sponsored vs. independent researchers planning clinical trials to evaluate medicinal effects of botanicals. Turmeric dietary supplements, a top selling botanical in the United States and focus of over 400 clinical trials to date, will be used throughout to illustrate both the promise and pitfalls associated with the clinical evaluation of botanicals.

Osteolytic effects of tumoral estrogen signaling in an estrogen receptor-positive breast cancer bone metastasis model

Aim:

Estrogen receptor α-positive (ER+) subtypes of breast cancer have the greatest predilection for forming osteolytic bone metastases (BMETs). Because tumor-derived factors mediate osteolysis, a possible role for tumoral ERα signaling in driving ER+ BMET osteolysis was queried using an estrogen (E₂)-dependent ER+ breast cancer BMET model.

Methods:

Female athymic Foxn1^nu mice were inoculated with human ER+ MCF-7 breast cancer cells via the left cardiac ventricle post-E₂ pellet placement, and age- and dose-dependent E₂ effects on osteolytic ER+ BMET progression, as well as direct bone effects of E₂, were determined.

Results:

Osteolytic BMETs, which did not form in the absence of E₂ supplementation, occurred with the same frequency in young (5-week-old) vs. skeletally mature (16-week-old) E₂ (0.72 mg)-treated mice, but were larger in young mice where anabolic bone effects of E₂ were greater. However, in mice of a single age and across a range of E₂ doses, anabolic E₂ bone effects were constant, while osteolytic ER+ BMET lesion incidence and size increased in an E₂-dose-dependent fashion. Osteoclasts in ER+ tumor-bearing (but not tumor-naive) mice increased in an E₂-dose dependent fashion at the bone-tumor interface, while histologic tumor size and proliferation did not vary with E₂ dose. E₂-inducible tumoral secretion of the osteolytic factor parathyroid hormone-related protein (PTHrP) was dose-dependent and mediated by ERα, with significantly greater levels of secretion from ER+ BMET-derived tumor cells.

Conclusion:

These results suggest that tumoral ERα signaling may contribute to ER+ BMET-associated osteolysis, potentially explaining the greater predilection for ER+ tumors to form clinically-evident osteolytic BMETs.

Association of EDARV370A with breast density and metabolic syndrome in Latinos

The ectodysplasin receptor (EDAR) is a tumor necrosis factor receptor (TNF) superfamily member. A substitution in an exon of EDAR at position 370 (EDARV370A) creates a gain of function mutant present at high frequencies in Asian and Indigenous American populations but absent in others. Its frequency is intermediate in populations of Mexican ancestry. EDAR regulates the development of ectodermal tissues, including mammary ducts. Obesity and type 2 diabetes mellitus are prevalent in people with Indigenous and Latino ancestry. Latino patients also have altered prevalence and presentation of breast cancer. It is unknown whether EDARV370A might connect these phenomena. The goals of this study were to determine 1) whether EDARV370A is associated with metabolic phenotypes and 2) if there is altered breast anatomy in women carrying EDARV370A. Participants were from two Latino cohorts, the Arizona Insulin Resistance (AIR) registry and Sangre por Salud (SPS) biobank. The frequency of EDARV370A was 47% in the Latino cohorts. In the AIR registry, carriers of EDARV370A (GG homozygous) had significantly (p < 0.05) higher plasma triglycerides, VLDL, ALT, 2-hour post-challenge glucose, and a higher prevalence of prediabetes/diabetes. In a subset of the AIR registry, serum levels of ectodysplasin A2 (EDA-A2) also were associated with HbA1c and prediabetes (p < 0.05). For the SPS biobank, participants that were carriers of EDARV370A had lower breast density and higher HbA1c (both p < 0.05). The significant associations with measures of glycemia remained when the cohorts were combined. We conclude that EDARV370A is associated with characteristics of the metabolic syndrome and breast density in Latinos.

Clinical Trials Evaluating Turmeric Dietary Supplement Treatment of Obesity-Associated Disorders of Glucose Metabolism or Bone

Curcumin-enriched turmeric dietary supplements (DS) are one of the top selling botanicals in the United States. Recent observational studies by our research group have documented turmeric DS use by almost a quarter of breast cancer survivors concurrent with anti-estrogen therapy and a third of those with rheumatoid arthritis. However, some recent reviews have suggested that there is no evidence of any biological effect of curcumin in humans, albeit without rigorous review of published reports. A scoping review of the literature was therefore undertaken to identify clinical trials testing oral curcumin-containing turmeric dietary supplements in humans. Using a defined search strategy, eight databases were reviewed (thru 05/29/2019), identifying 4767 potential English language reports for inclusion, from which all but n = 315 were excluded after review by three independent observers. The majority of studies reported significant effects of turmeric DS on clinical endpoints. Obesity-associated disorders of glucose and lipid metabolism (n =69, including type 2 diabetes mellitus [T2DM], metabolic syndrome and/or hyperlipidemia) or musculoskeletal disorders (n = 46), of which half related to osteoarthritis, were among the most commonly studied diseases in turmeric DS clinical trials, with reported benefits related to inhibition of inflammation, amelioration of hyperlipidemia, increases in adiponectin, and improved glucose control. As is common for botanical clinical trials, the quality of the studies were variable due to lack of clarity about product content as well as study design (e.g. only 60% of T2DM trials and 74% of osteoarthritis trials were randomized, placebo-controlled and double-blinded). However, particularly with respect to treatment of osteoarthritis and metabolic consequences of insulin resistance, the preponderance of the data were suggestive of beneficial physiologic effects. Given the current widespread use of turmeric DS by Americans and existing evidence of possible clinical benefits, further evaluation of turmeric DS efficacy and safety may be warranted.

A Role for TGFβ Signaling in Preclinical Osteolytic Estrogen Receptor-Positive Breast Cancer Bone Metastases Progression

While tumoral Smad-mediated transforming growth factor β (TGFβ) signaling drives osteolytic estrogen receptor α-negative (ER-) breast cancer bone metastases (BMETs) in preclinical models, its role in ER+ BMETs, representing the majority of clinical BMETs, has not been documented. Experiments were undertaken to examine Smad-mediated TGFβ signaling in human ER+ cells and bone-tropic behavior following intracardiac inoculation of estrogen (E2)-supplemented female nude mice. While all ER+ tumor cells tested (ZR-75-1, T47D, and MCF-7-derived) expressed TGFβ receptors II and I, only cells with TGFβ-inducible Smad signaling (MCF-7) formed osteolytic BMETs in vivo. Regulated secretion of PTHrP, an osteolytic factor expressed in >90% of clinical BMETs, also tracked with osteolytic potential; TGFβ and E2 each induced PTHrP in bone-tropic or BMET-derived MCF-7 cells, with the combination yielding additive effects, while in cells not forming BMETs, PTHrP was not induced. In vivo treatment with 1D11, a pan-TGFβ neutralizing antibody, significantly decreased osteolytic ER+ BMETs in association with a decrease in bone-resorbing osteoclasts at the tumor-bone interface. Thus, TGFβ may also be a driver of ER+ BMET osteolysis. Moreover, additive pro-osteolytic effects of tumoral E2 and TGFβ signaling could at least partially explain the greater propensity for ER+ tumors to form BMETs, which are primarily osteolytic.

Intraspecific trait variation in plants: a renewed focus on its role in ecological processes

BACKGROUND

Investigating the causes and consequences of intraspecific trait variation (ITV) in plants is not novel, as it has long been recognized that such variation shapes biotic and abiotic interactions. While evolutionary and population biology have extensively investigated ITV, only in the last 10 years has interest in ITV surged within community and comparative ecology.

SCOPE

Despite this recent interest, still lacking are thorough descriptions of ITV's extent, the spatial and temporal structure of ITV, and stronger connections between ITV and community and ecosystem properties. Our primary aim in this review is to synthesize the recent literature and ask: (1) How extensive is intraspecific variation in traits across scales, and what underlying mechanisms drive this variation? (2) How does this variation impact higher-order ecological processes (e.g. population dynamics, community assembly, invasion, ecosystem productivity)? (3) What are the consequences of ignoring ITV and how can these be mitigated? and (4) What are the most pressing research questions, and how can current practices be modified to suit our research needs? Our secondary aim is to target diverse and underrepresented traits and plant organs, including anatomy, wood, roots, hydraulics, reproduction and secondary chemistry. In addressing these aims, we showcase papers from the Special Issue.

CONCLUSIONS

Plant ITV plays a key role in determining individual and population performance, species interactions, community structure and assembly, and ecosystem properties. Its extent varies widely across species, traits and environments, and it remains difficult to develop a predictive model for ITV that is broadly applicable. Systematically characterizing the sources (e.g. ontogeny, population differences) of ITV will be a vital step forward towards identifying generalities and the underlying mechanisms that shape ITV. While the use of species means to link traits to higher-order processes may be appropriate in many cases, such approaches can obscure potentially meaningful variation. We urge the reporting of individual replicates and population means in online data repositories, a greater consideration of the mechanisms that enhance and constrain ITV's extent, and studies that span sub-disciplines.

Influence of Changes in Soft Tissue Composition on Changes in Bone Strength in Peripubertal Girls: The STAR Longitudinal Study

Obesity and osteoporosis remain two major public health concerns. Soft tissue composition and bone are interrelated; however, it is still not well understood how changes in adiposity during adolescence affect bone development. The aim of this study was to assess how changes in DXA-derived total body lean mass (TBLM) and total body fat mass (TBFM) associate with 2-year changes in bone outcomes at the 20% femur, 66% tibia, 66% radius, and 4% tibia, as measured by pQCT, during the years surrounding the onset of menarche in a cohort of 9- to 12-year-old (baseline) adolescent girls (70% Hispanic). From baseline to 2-year follow-up, girls showed statistically significant increases in all bone outcomes, except radial endosteal circumference. In separate linear regression models, change in TBLM and change in TBFM were both positively associated with 2-year changes in bone outcomes at all measured bone sites, after controlling for relevant covariates. However, when change in TBLM and change in TBFM were included in the same model, change in TBLM was the predominant predictor of bone outcomes, explaining 4% to 14% of the variance in bone strength outcomes. Change in TBFM remained a positive predictor of tibia polar strength strain index (SSI_p) (2% variance explained). A significant interaction between change in TBFM and menarcheal status was identified at the radius for SSI_p and indicated that greater gains in TBFM were beneficial for SSI_p in girls that were premenarcheal at baseline but detrimental for girls who were postmenarcheal at baseline. The overall findings suggest that changes in TBLM during the peripubertal years have a greater influence on bone outcomes than changes in TBFM. While gains in TBFM might benefit the weight bearing 66% tibia, greater gains in TBFM may be detrimental to bone development at the non-weight bearing 66% radius after the onset of menarche. © 2020 American Society for Bone and Mineral Research (ASBMR).

Nonvitamin, Nonmineral Dietary Supplement Use in Individuals with Rheumatoid Arthritis

BACKGROUND

Over-the-counter, natural product-based (nonvitamin, nonmineral) dietary supplement (NVNM DS) use is common in adults with rheumatoid arthritis (RA), a group at risk for drug-DS interactions, due to polypharmacy, but this use is underreported to health care providers. Recent dramatic changes in US sales of specific NVNM DS suggest that the prevalence and types of NVNM DS used in RA populations may also have shifted.

OBJECTIVES

A study was undertaken to identify current and past use of specific NVNM DS for RA disease treatment and to examine associations between use of NVNM DS, RA pharmaceuticals, and/or vitamin or mineral (VM) DS.

METHODS

We developed a survey instrument to capture current and ever use of specific NVNM DS, VM DS, and RA pharmaceuticals, with 696 subjects self-reporting an RA diagnosis recruited online or in clinic for survey participation. Analyses were limited to 611 subjects reporting RA diagnosis after age 18 y and treatment with specific RA pharmaceuticals.

RESULTS

Most participants reported DS use, with current usage prevalence 49.6% (n = 303), 83.5% (n = 510), or 87.6% (n = 535) for NVNM, VM, or any DS, respectively. While not having appeared in previous RA surveys, turmeric and ginger were among the top 3 NVNM DS in current use, along with fish oil/ω-3 (n-3) PUFA. Concurrent NVNM DS use was reported by 48.2% (n = 243) of participants currently using RA pharmaceuticals (n = 504) and was more common in those using disease-modifying antirheumatic drugs only (no biologics). Most methotrexate users (83%) reported concurrent folate supplementation, with one-third also using turmeric, which is notable because methotrexate and turmeric have been associated with hepatotoxicity.

CONCLUSION

Individuals with RA commonly use NVNM DS in combination with RA pharmaceuticals, including a previously undocumented but popular use of turmeric or ginger supplements with an unclear risk/benefit ratio.

Bone-Specific Metabolism of Dietary Polyphenols in Resorptive Bone Diseases

SCOPE

Curcumin prevents bone loss in resorptive bone diseases and inhibits osteoclast formation, a key process driving bone loss. Curcumin circulates as an inactive glucuronide that can be deconjugated in situ by bone's high β-glucuronidase (GUSB) content, forming the active aglycone. Because curcumin is a common remedy for musculoskeletal disease, effects of microenvironmental changes consequent to skeletal development or disease on bone curcumin metabolism are explored.

METHODS AND RESULTS

Across sexual/skeletal development or between sexes in C57BL/6 mice ingesting curcumin (500 mg kg-1 ), bone curcumin metabolism and GUSB enzyme activity are unchanged, except for >twofold higher (p < 0.05) bone curcumin-glucuronide substrate levels in immature (4-6-week-old) mice. In ovariectomized (OVX) or bone metastasis-bearing female mice, bone substrate levels are also >twofold higher. Aglycone curcumin levels tend to increase proportional to substrate such that the majority of glucuronide distributing to bone is deconjugated, including OVX mice where GUSB decreases by 24% (p < 0.01). GUSB also catalyzes deconjugation of resveratrol and quercetin glucuronides by bone, and a requirement for the aglycones for anti-osteoclastogenic bioactivity, analogous to curcumin, is confirmed.

CONCLUSION

Dietary polyphenols circulating as glucuronides may require in situ deconjugation for bone-protective effects, a process influenced by bone microenvironmental changes.

Mechanistic Differences in the Inhibition of NF-κB by Turmeric and Its Curcuminoid Constituents

Turmeric extract, a mixture of curcumin and its demethoxy (DMC) and bisdemethoxy (BDMC) isomers, is used as an anti-inflammatory preparation in traditional Asian medicine. Curcumin is considered to be the major bioactive compound in turmeric but less is known about the relative anti-inflammatory potency and mechanism of the other components, their mixture, or the reduced in vivo metabolites. We quantified inhibition of the NF-κB pathway in cells, adduction to a peptide mimicking IκB kinase β, and the role of cellular glutathione as a scavenger of electrophilic curcuminoid oxidation products, suggested to be the active metabolites. Turmeric extracts (IC₅₀ 14.5 ± 2.9 μM), DMC (IC₅₀ 12.1 ± 7.2 μM), and BDMC (IC₅₀ 8.3 ± 1.6 μM), but not reduced curcumin, inhibited NF-κB similar to curcumin (IC₅₀ 18.2 ± 3.9 μM). Peptide adduction was formed with turmeric and DMC but not with BDMC, and this correlated with their oxidative degradation. Inhibition of glutathione biosynthesis enhanced the activity of DMC but not BDMC in the cellular assay. These findings suggest that NF-κB inhibition by curcumin and DMC involves their oxidation to reactive electrophiles, whereas BDMC does not require oxidation. Because it has not been established whether curcumin undergoes oxidative transformation in vivo, oxidation-independent BDMC may be a promising alternative to test in clinical trials.

Incomplete Hydrolysis of Curcumin Conjugates by β-Glucuronidase: Detection of Complex Conjugates in Plasma

SCOPE

The diphenol curcumin from turmeric is rapidly metabolized into phase II conjugates following oral administration, resulting in negligible plasma concentration of the free compound, which is considered the bioactive form. Total plasma concentration of curcumin is often quantified after treatment with β-glucuronidase to hydrolyze curcumin-glucuronide, the most abundant conjugate in vivo. The efficiency of enzymatic hydrolysis has not been tested.

METHODS AND RESULTS

Using liquid chromatography-mass spectrometry (LC-MS) analyses the efficiency of β-glucuronidase and sulfatase from Helix pomatia is compared to hydrolyze curcumin conjugates in human and mouse plasma after oral administration of turmeric. Both β-glucuronidase and sulfatase completely hydrolyze curcumin-glucuronide. Unexpectedly, β-glucuronidase hydrolysis is incomplete, affording a large amount of curcumin-sulfate, whereas sulfatase hydrolyzed both glucuronide and sulfate conjugates. With sulfatase, the concentration of free curcumin is doubled in human and increased in mouse plasma compared to β-glucuronidase treatment. Incomplete hydrolysis by β-glucuronidase suggests the presence of mixed glucuronide-sulfate conjugates. LC-MS based searches detect diglucuronide, disulfate, and mixed sulfate-glucuronide and sulfate-diglucuronide conjugates in plasma that likely contribute to the increase of free curcumin upon sulfatase treatment.

CONCLUSION

β-Glucuronidase incompletely hydrolyzes complex sulfate-containing conjugates that appear to be major metabolites, resulting in an underestimation of the total plasma concentration of curcumin.

Abstract 3002: Bone-protective curcumin circulates as a pro-drug conjugate that is activated in bone by β-glucuronidase

Curcumin (CURC), a turmeric-derived dietary polyphenol, prevents osteoclast formation and bone resorption in murine models of arthritis, post-menopausal osteoporosis, and bone metastatic breast cancer despite being rapidly conjugated upon ingestion in both rodents and humans to form curcumin-glucuronide (G-CURC). However, recent studies from our laboratory demonstrate that aglycone CURC is enriched in bone relative to the circulation. Studies were therefore undertaken to compare the anti-resorptive effects of aglycone CURC vs G-CURC and to elucidate mechanisms responsible for enrichment of aglycone CURC in bone, including clinically relevant influences of age, sex, and reproductive status.

CURC dose-dependently inhibited RANKL-stimulated osteoclast formation in RAW264.7 cell cultures, while G-CURC was without effect. Likewise, CURC dose-dependently inhibited TGFβ-stimulated PTHrP secretion from MDA-MB-231 breast cancer cells, which readily form PTHrP-driven osteolytic bone metastases in vivo.

In wild type (WT) C57BL/6J mice, heparanase (HPSE) and β-glucuronidase (GUSB) were the only enzymes with reported deglucuronidation activity expressed in bone (Western). However, only GUSB was able to recognize G-CURC as a substrate, deconjugating G-CURC to form CURC (LC/MS). Consistent with these findings, tissue-specific levels of CURC were highest in bone (vs. heart, muscle, or kidney) and proportional to tissue specific GUSB enzyme activity.

To verify the role of GUSB in CURC bone enrichment, CURC metabolism and GUSB enzyme expression and activity were compared among mice with normal levels of GUSB (C57BL/6J) vs. partial (C3H/HeJ) or complete (mucopolysaccharidosis VII (mps/mps]) deficiencies in GUSB expression. As expected, partial (55% of WT) or complete deficiencies in GUSB expression significantly reduced CURC enrichment in bone.

While GUSB can be positively regulated by pharmacologic doses of androgens, neither male sex nor ovariectomy (OVX) altered GUSB activity (per protein) in bone relative to intact females, although a small but statistically significant increase in free curcumin was demonstrated in males (17%) and OVX females (10%). Age did not significantly change the enrichment of CURC in bone of 4 vs 28-week mice.

These findings suggest bio-inactive G-CURC acts as pro-drug that is converted to active CURC within bone, independent of sex, age or reproductive status, where it can inhibit the formation of bone resorbing osteoclasts or secretion of osteolytic PTHrP from breast cancer bone metastases.

Citation Format: Andrew Kunihiro, Julia A. Brickey, jennifer B. Frye, Paula B. Luis, Claus Schneider, Janet L. Funk. Bone-protective curcumin circulates as a pro-drug conjugate that is activated in bone by β-glucuronidase [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3002.

Abstract 2042: Modeling estrogen receptor-positive breast cancer bone metastasis to query osteolytic effects of tumor ER signaling

Estrogen receptor α-positive (ER+) breast cancers (BrCAs) have the greatest predilection for forming clinically evident bone metastases (BMETs). To query ERα’s role in osteolytic BrCA BMET progression, tumoral vs bone microenvironment effects of 17β-estradiol (E2) were determined in a human xenograft murine model of ER+ BrCA BMET. Female athymic mice aged 4 weeks (young) or 15 weeks (mature) were inoculated with 1x105 human ER+ MCF-7 BrCA cells via the left cardiac ventricle 2 days post-placement of 60-day release E2 pellets (0.05, 0.10, 0.18, 0.36, & 0.72 mg E2). Osteolytic BMET formation was assessed radiographically and E2effects on bone were determined by DXA and microCT at various time points. The BMET size and proliferation were assessed by immunohistochemical (IHC) analyses at the end of the experiment (42 days). The effect of E2 on tumoral secretion of the osteolytic factor, parathyroid hormone related protein (PTHrP), was determined using a commercially available radioimmunoassay. The incidence and size of osteolytic BMET, which were not evident in the absence of E2 supplementation, were E2 dose-dependent in young mice. In contrast, E2 effects on the bone microenvironment were not dose-dependent, and resulted in identical increases in bone mineral density (BMD) and bone volume (BV/TV). In skeletally immature (young) mice vs skeletally mature mice treated with an identical E2 dose (0.72 mg), which caused significantly different effects on bone turnover, progression of E2-dependent BMET was identical. These results suggest that E2 effects on the tumor, rather than bone, were driving E2-dependency of BMET progression. IHC analysis demonstrated that neither the size of human cytokeratin-positive tumors nor the proportion of Ki67-positive proliferating tumor cells in bone were E2 dose-dependent, suggesting that proliferative effects of E2 could not explain E2-dose dependent differences in osteolytic BMET formation. PTHrP, an osteolytic factor expressed in most clinical BrCA BMET, was E2-inducible ex vivo and secreted in higher levels by tumor cells isolated from BMETs. These results suggest that during ER+ BrCA BMET progression, tumoral effects of E2 not only support ER+ BMET proliferation, but may also have bone-specific effects due to the induction of PTHrP, which may explain the marked osteolytic capacity of the ER+ tumor cells in this model despite a microenvironment where bone volume is markedly increased.

Citation Format: Julia N. Cheng, Jennifer B. Frye, Susan A. Whitman, Andrew G. Kunihiro, Madison M. Egan, Julia A. Brickey, Lily A. Alvord, Janet L. Funk. Modeling estrogen receptor-positive breast cancer bone metastasis to query osteolytic effects of tumor ER signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2042.

Natural Product Dietary Supplement Use by Individuals With Rheumatoid Arthritis: A Scoping Review

OBJECTIVE

Natural product dietary supplements (NDS), defined as non-mineral, non-vitamin, ingested, natural product-derived, substances, are the most frequently used complementary and alternative medicine modality in the US, with musculoskeletal disease being the most frequent reason for their use. Because NDS usage is frequently unreported, and patients with RA may be at higher risk for NDS-related side effects due the underlying nature of the disease and frequent use of complex pharmaceutical regimens, a scoping review of the literature was undertaken to examine population-based patterns of NDS use for RA self-management.

METHODS

Using guidelines for scoping reviews, Allied and Complementary Medicine, the Cumulative Index to Nursing and Allied Health Literature, the Cochrane Library, Embase, Ovid/Medline, and Web of Science databases were searched to identify references presenting primary data related to the prevalence or patterns of use of NDS in RA populations.

RESULTS

Twenty-three studies, which were published between 1980 and 2015 and conducted in 11 countries, met the inclusion criteria. The overall prevalence of NDS use in patients with RA was 47% worldwide and did not differ by geographic region. On average, 47% of patients found NDS to be effective and 13% reported adverse side effects, with only 30% informing their physicians about the use of NDS, which in a majority of cases were used concomitantly with RA pharmaceuticals. Marine oils, glucosamine, vinegar, and chondroitin were among the most commonly reported NDS worldwide.

CONCLUSION

Given the apparent communication gap between patients and providers regarding NDS use and higher potential risks associated with this usage in RA, ongoing surveillance of population-based practices may help facilitate RA management and direct future NDS research.

Translational Investigation of Turmeric for Arthritis Treatment: A Review of Lessons Learned

Turmeric rhizome has been used for centuries to combat inflammation, including joint inflammation in arthritis. However, scientific evidence of efficacy and mechanism of action and a systematic evaluation of the biological activity of turmeric components for the treatment of inflammation have been lacking. This review will summarize the results of recently published studies that we have conducted to address each of these specific areas of inquiry using an animal model of rheumatoid arthritis.

Beta-Glucuronidase Catalyzes Deconjugation and Activation of Curcumin-Glucuronide in Bone

The biological basis for documented in vivo bone-protective effects of turmeric-derived curcumin is unclear since curcumin is barely detectable in serum, being rapidly conjugated to form what is thought to be an inactive glucuronide. Studies were therefore undertaken to test the postulate that antiresorptive effects of curcumin require deconjugation within bone to form the bioactive aglycone and that β-glucuronidase (GUSB), a deconjugating enzyme expressed by hematopoietic marrow cells, facilitates this site-specific transformation. Consistent with this postulate, aglycone, but not glucuronidated, curcumin inhibited RANKL-stimulated osteoclastogenesis, a key curcumin target in bone. Aglycone curcumin, expressed relative to total curcumin, was higher in bone marrow than in serum of curcumin-treated C57BL/6J mice, while remaining a minor component. Ex vivo, under conditions preventing further metabolism of the unstable aglycone, the majority of curcumin-glucuronide delivered to marrow in vivo was hydrolyzed to the aglycone, a process that was inhibited by treatment with saccharolactone, a GUSB inhibitor, or in mice having reduced (C3H/HeJ) or absent (mps/mps) GUSB activity. These findings suggest that curcumin, despite low systemic bioavailability, may be enzymatically activated (deconjugated) within GUSB-enriched bone to exert protective effects, a metabolic process that could also contribute to bone-protective effects of other highly glucuronidated dietary polyphenols.

Relationship of cardiometabolic risk biomarkers with DXA and pQCT bone health outcomes in young girls

BACKGROUND

Excess weight exerts the positive effect of mechanical loading on bone during development whereas obesity-related metabolic dysfunction may have a detrimental impact. In adults, the presence of metabolic syndrome and type 2 diabetes has been associated with compromised bone density, quality, and strength, and an increased incidence of fractures. The few studies that have investigated the role of cardio-metabolic disease risk biomarkers (CMR) on bone strength in children have given conflicting results. The aim of this study was to assess the combined and independent relationships of cardio-metabolic biomarkers with total body and regional bone parameters in young girls.

METHODS

In 306, 9-12 year old girls, measures of whole body fat and lean mass, areal bone mineral density (aBMD), bone mineral content (BMC), and bone area (BA) were obtained by dual-energy x-ray absorptiometry (DXA). Bone mineral density (vBMD), geometry, and strength of metaphyseal and diaphyseal regions of the femur and tibia and a diaphyseal region of the radius were measured using peripheral quantitative computed tomography (pQCT). Fasting serum measures of CMRs included, fasting glucose, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), high-density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglyceride (TG), systolic and diastolic blood pressure (SBP and DBP), and C-reactive protein (CRP). Multiple linear regression was used to assess the independent associations of a single CMR with total body and peripheral measures of bone strength after controlling for the other CMRs, plus total body soft tissue, and other relevant covariates. Also, a standardized total CMR composite score, calculated by standardizing to z-scores and then summing z-scores of each CMR biomarker, was regressed with total body and regional bone measures to assess the relationship of a cluster of risk factors with bone health.

RESULTS

Total CMR composite score had inverse associations (p < 0.001) with DXA total BMC and BA. Inverse associations (p < 0.05) of CMR risk score with pQCT regional bone measures occurred with total and trabecular BA at the 4% tibia. Of the individual CMRs, HOMA-IR and CRP were significant predictors of total body bone measures by DXA accounting for ~1-5% of the variance in BMC, BA, and/or aBMD. HOMA-IR was the main predictor of regional pQCT bone outcomes, accounting for the most variance in trabecular vBMD (2.6%) and BSI (3.8%) at the 4% tibia. Most markers of dyslipidemia (TG, HDL-C, LDL-C) and hypertension (SBP, DBP) were not associated (p > 0.05) with any total body or regional bone outcomes with the exception of the inverse relationship of LDL-C with total and trabecular BA and the positive relationship of DBP with cortical vBMD at the radius.

CONCLUSION

Of the obesity-related metabolic impairments, insulin resistance and chronic inflammation may compromise whole body bone development in young girls. In particular, trabecular bone, such as that found at the metaphysis of long bones, may be more susceptible to the detrimental effects associated with obesity-related metabolic dysfunction.

Drug-induced autoimmune hepatitis associated with turmeric dietary supplement use

Turmeric dietary supplement sales, which accounted for US$69 million in spending in 2016, have been increasing exponentially in the USA, making this one of the most popular botanical supplements sold in the USA. Herbal supplement use, which is generally regarded as safe by consumers, is not usually reported to healthcare providers. We reported here on a case of autoimmune hepatitis, occurring in a 71-year-old woman taking turmeric dietary supplements for the maintenance of cardiovascular health, which resolved rapidly following discontinuation of the turmeric supplements. Of particular note, turmeric use was not documented in the patient's medical records and the potential causative role of the turmeric supplementation was ultimately identified by the patient rather than the healthcare providers. To our knowledge, this is the first documented report of turmeric supplement-induced autoimmune hepatitis.

Relationship between fat distribution and cardiometabolic risk in Hispanic girls

OBJECTIVE

In adults, certain body fat depots have greater impact on cardiometabolic risk than total adiposity. Whether similar relationships exist in children is uncertain. The aim of this study was to examine the relationships among dual x-ray absorptiometry (DXA) measures of body fat distribution and total body adiposity with cardiometabolic risk factors in Hispanic girls.

METHODS

Measures of total percent body fat, percent of total fat within the android, gynoid, leg, and trunk regions, and cardiometabolic biomarkers (insulin, glucose, homeostatic model assessment of insulin resistance (HOMA-IR), triglycerides (TG), low and high lipoprotein cholesterol (LDL-C, HDL-C)) were obtained from 232 Hispanic girls (age 10.7 ±1.1 years). Regression models for each metabolic parameter were run against adiposity measures. Partial correlations of the adiposity measures were used to compare associations between adiposity measures and the cardiometabolic risk factors, controlling for somatic maturation.

RESULTS

Total and regional adiposity were significantly related with cardiometabolic risk factors (P < 0.05) except fasting glucose. The partial correlations of total and regional adiposity measures with each cardiometabolic biomarker were similar. More variance was explained for insulin and the HOMA-IR (33%-43%) than other risk factors. Partial correlations for the percentage of total fat in the gynoid and leg regions with insulin, HOMA-IR, TG, and LDL-C were negative, and positive with HDL-C.

CONCLUSION

Measures of total and regional fat perform similarly in predicting cardiometabolic risk in Hispanic girls. A higher proportion of fat distributed in the gynoid or leg region is associated with lower cardiometabolic risk.

Relative contributions of lean and fat mass to bone strength in young Hispanic and non-Hispanic girls

BACKGROUND

With the high prevalence of childhood obesity, especially among Hispanic children, understanding how body weight and its components of lean and fat mass affect bone development is important, given that the amount of bone mineral accrued during childhood can determine osteoporosis risk later in life. The aim of this study was to assess the independent contributions of lean and fat mass on volumetric bone mineral density (vBMD), geometry, and strength in both weight-bearing and non-weight-bearing bones of Hispanic and non-Hispanic girls.

METHODS

Bone vBMD, geometry, and strength were assessed at the 20% distal femur, the 4% and 66% distal tibia, and the 66% distal radius of the non-dominant limb of 326, 9- to 12-year-old girls using peripheral quantitative computed tomography (pQCT). Total body lean and fat mass were measured by dual-energy x-ray absorptiometry (DXA). Multiple linear regression was used to assess the independent relationships of fat and lean mass with pQCT bone measures while adjusting for relevant confounders. Potential interactions between ethnicity and both fat and lean mass were also tested.

RESULTS

Lean mass was a significant positive contributor to all bone outcomes (p < 0.05) with the exception of vBMD at diaphyseal sites. Fat mass was a significant contributor to bone strength at weight bearing sites, but did not significantly contribute to bone strength at the non-weight bearing radius and was negatively associated with radius cortical content and thickness. Bone measures did not significantly differ between Hispanic and non-Hispanic girls, although there was a significant interaction between ethnicity and fat mass with total bone area at the femur (p = 0.02) and 66% tibia (p = 0.005) as well as bone strength at the femur (p = 0.03).

CONCLUSION

Lean mass is the main determinant of bone strength for appendicular skeletal sites. Fat mass contributes to bone strength in the weight-bearing skeleton but does not add to bone strength in non-weight-bearing locations and may potentially be detrimental. Bone vBMD, geometry, and strength did not differ between Hispanic and non-Hispanic girls; fat mass may be a stronger contributor to bone strength in weight-bearing bones of Hispanic girls compared to non-Hispanic.

Abstract 2685: Targeting TGFβ signaling pathways in bone metastatic breast cancer cells to limit metastatic progression using curcuminoids, a turmeric-derived natural product

Tumor-cell TGFβ signaling has been demonstrated to drive osteolytic breast cancer bone metastases (BrCa BMET) in mouse models. This established an important link between the microenvironment and tumor cells in bone, wherein osteoclast-mediated bone resorption stimulates the release of TGFβ from bone matrix, which induces tumoral secretion of osteolytic factors, such as parathyroid-related protein (PTHrP) that drive further osteoclast-mediated bone destruction in a positive feedback loop. These findings have prompted interest in the use of pharmacologic TGFβ inhibitors, currently under development, for the treatment of BrCa BMET. Interestingly, studies have demonstrated antagonistic effects of a natural product, turmeric-derived polyphenols called curcuminoids (CURC), on BrCa BMET progression and TGFβ-inducible, Smad-dependent signaling in a TGFβ-dependent human xenograft model (human MDA-MB-231 [MDA-SA]).The studies described here were undertaken to determine whether this inhibitory effect is generalizable to other BrCa cells that form TGFβ-dependent BMETs (human MDA-1833 and MDA-2287; murine 4T1) and to begin to elucidate the mechanism by which CURC block BrCa cell TGFβ signaling. Analogous to prior findings using MDA-SA cells forming BMET that are dependent on TGFβ-inducible tumoral secretion of PTHrP via Smad and non-Smad (specifically, p38) dependent pathways, CURC inhibited TGFβ inducible activation (phosphorylation) of receptor Smad2 (Western) in all TGFβ-dependent BrCa cell lines tested.In MDA-SA cells, CURC inhibition of TGFβ-stimulated Smad2 phosphorylation was time- and dose-dependent (Western), and associated with decreased expression of a Smad-dependent luciferase reporter gene in transiently transfected cells. In both MDA-SA and 4T1 cells, these changes were accompanied by decreased TGFβ-stimulated PTHrP secretion (RIA). These effects in MDA-SA cells were not associated with changes in the expression of canonical TGFβ signaling proteins, such as Smad anchor for receptor activation (SARA), which is involved in Smad phosphorylation, or Smad4, a required cofactor for Smad-mediated gene transcription. Also unchanged were noncanonical TGFβ-stimulated, Smad-independent signaling pathways (e.g., p38, ERK1/2 or JNK). Of note, however, in all cell lines tested, CURC inhibition of Smad2 phosphorylation was accompanied by a decrease in constitutive Smad2 levels, with variable decreases in the ratio of phosphorylated vs. total Smad levels. These results suggest that CURC can specifically and uniformly inhibit Smad-regulated TGFβ signaling in bone metastatic BCa cells forming TGFβ-dependent osteolytic lesions, an effect that may be mediated, at least in part, by changes in constitutive levels of receptor-regulated Smad expression.

Citation Format: Andrew Kunihiro, Julia A. Brickey, Jen B. Frye, Janet L. Funk. Targeting TGFβ signaling pathways in bone metastatic breast cancer cells to limit metastatic progression using curcuminoids, a turmeric-derived natural product [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2685.

Curcuminoid Content and Safety-Related Markers of Quality of Turmeric Dietary Supplements Sold in an Urban Retail Marketplace in the United States

SCOPE

Turmeric is a top selling dietary supplement (DS) in the United States with rapidly expanding usage. Therefore, turmeric DS formulations available for sale in an urban US retail marketplace are analyzed, and point of sale information is related to measures of quality relevant to safety.

METHODS AND RESULTS

Eighty-seven unique turmeric DS are identified; a majority (94%) contained turmeric-derived curcuminoid extracts (TD-CE), which are combined with other bioactives in 47% of products, including piperine (24%), an additive that could alter the metabolism of concurrent medications. While curcuminoid content is within 80% of anticipated for a majority of products analyzed (n = 35), curcuminoid composition (% curcumin) did not meet US Pharmacopeia (USP) criteria for TD-CE in 59% and is suggestive of possible unlabeled use of synthetic curcumin in some. Lead content is associated with the inclusion of turmeric root and exceeded USP limits in one product. Residues of toxic class 1 or 2 solvents, which are not needed for TD-CE isolation, are present in 71% of products, although quantified levels were within USP-specified limits.

CONCLUSION

Assessment of turmeric DS quality at point of sale is difficult for consumers and may best be managed in partnership with knowledgeable healthcare professionals.

Abstract 2116: Tumor-specific effects of estrogen drive a murine model of human estrogen receptor-positive breast cancer bone metastasis independent of bone microenvironment changes

Estrogen receptor α-positive (ER+) breast cancers (BrCAs) have the greatest predilection for forming bone metastases (BMETs). To begin to query ERα's role in osteolytic BrCA BMET progression, tumoral vs bone microenvironment effects of 17β-estradiol (E2) were determined in a human xenograft murine model of ER+ BrCA BMET. For these studies, naïve or 17β-estradiol (E2)-treated female athymic mice aged 4 weeks (young) or 15 weeks (mature) were inoculated with 1x105 human ER+ MCF-7 BrCA cells via the left cardiac ventricle 2 days post-placement of 60-day release E2 pellets (0.05, 0.10, 0.18, 0.36, & 0.72 mg E2). For studies examining E2 effects on bone, MCF-7 cells were not inoculated. Osteolytic lesion formation was assessed by hind limb radiographs, and E2 effects on bone were assessed by DXA (Faxitron), μCT (Scanco), and biochemical markers of bone formation or resorption (P1NP and TRAcP, respectively; Immunodiagnostic Systems). BMET incidence and lesion size in young mice were E2 dose-dependent, achieving 100% incidence at the highest dose tested, with smaller lesions and lower incidence occurring in response to lower doses, and no lesions forming in the absence of E2 even after 8 months. In contrast, E2 effects on the bone microenvironment were not dose dependent, and resulted in identical increases in bone mineral density (BMD) and bone volume (BV/TV), primarily via an increase in bone formation. To further query the importance of tumoral vs bone effects of E2 in driving ER+ BrCA progression, the tumoral effects of an identical E2 dose (0.72 mg) were compared in the skeletally immature young mice, which accrued increased bone (BV/TV) due to increases in bone formation in response to E2, vs skeletally mature mice, where E2-induced increases in bone were less marked and primarily driven by decreases in bone resorption. In these two very different bone milieus, progression of E2-dependent BMET was identical. While the relative roles of E2-induced tumor cell proliferation vs osteolytic factor secretion cannot be distinguished here, the development of osteolytic lesions similar in size to those occurring in ER- models driven by tumoral secretion of osteolytic factors, despite a marked increase in bone volume, suggests that tumoral effects of E2 may drive osteolytic ER+ BrCA BMET progression in a bone-specific fashion.

Citation Format: Julia N. Cheng, Jennifer B. Frye, Susan A. Whitman, Andrew G. Kunihiro, Madison M. Egan, Julia A. Brickey, Janet L. Funk. Tumor-specific effects of estrogen drive a murine model of human estrogen receptor-positive breast cancer bone metastasis independent of bone microenvironment changes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2116.

Effect of cardiometabolic risk factors on the relationship between adiposity and bone mass in girls

BACKGROUND/OBJECTIVE

Childhood obesity has been separately associated with cardiometabolic risk factors (CMRs) and increased risk of fracture. However, both augmented and compromised bone mass have been reported among overweight/obese children. Metabolic dysfunction, often co-existing with obesity, may explain the discrepancy in previous studies. The aim of this study was to examine whether the relationship between adiposity and dual-energy X-ray absorptiometry (DXA) derived bone mass differed in young girls with and without CMR(s).

SUBJECTS/METHODS

Whole-body bone and body composition measures by DXA and measures of CMR (fasting glucose, high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), systolic and diastolic blood pressure, waist circumference (WC)) were obtained from 307, 9- to 12-year-old girls. Girls with 1 or ≥ 2 CMR(s) were considered to be at risk (vs. no CMR). Multiple linear regression was used to test the relationship of total fat mass with total body bone mineral content (BMC) after controlling for height, lean mass, CMR risk, and other potential confounders.

RESULTS

There was a significant interaction between CMR risk and total body fat mass. When girls were stratified by CMR group, all groups had a significant positive relationship between fat mass and BMC (p < 0.05), however, girls with ≥ 2 CMRs had a lower BMC for a given level of body fat. Total body fat was not significantly related to bone mineral density (p > 0.05).

CONCLUSION

Fat mass has a positive relationship with BMC even after controlling for lean mass. However, the positive relationship of fat mass with BMC may be attenuated if multiple CMRs are present.

Abstract P4-06-08: Characterization of an estrogen-dependent murine model of human estrogen receptor-positive breast cancer bone metastasis

Introduction: Breast cancer patients with estrogen receptor-positive (ER+) tumors have the highest rate of developing clinically evident osteolytic bone metastasis. However, much of our knowledge of breast cancer bone metastasis has been derived from ER- murine xenograft models, as robust pre-clinical models of ER+ bone metastasis are currently lacking. Thus we sought to develop and characterize a murine xenograft model of breast cancer bone metastases using an estrogen-dependent ER+ MCF-7 cell line.

Methods: 28-day-old female nude mice were implanted with the following 60-day extended-release 17β-estradiol (E2) pellets: 0.72, 0.36, 0.18, 0.10, or 0.05 mg; with or without 1x105 MCF-7 cells (ATCC) inoculated via the left cardiac ventricle. Non-estradiol-supplemented female nude mice were also inoculated with either MCF-7 cells or a well-characterized, bone-tropic human ER- MDA-MB-231 cell line (referred to as MDA-SA), used as a comparison model. Radiographs and dual-energy X-ray absorptiometry's (DXAs) of hind femurs and tibias were obtained weekly to assess osteolytic lesion formation and BMD, respectively. Statistical significance was analyzed using one-way ANOVA with Tukey's post-hoc testing.

Results: Using E2 doses previously reported in the literature to promote MCF-7 orthotopic tumors and bone metastases (0.72 mg 60-day 17β- E2 pellets), bone metastases developed with 100% incidence (n = 13) by day 28 in the MCF-7 model, with osteolytic lesion area increasing to 10.3±0.8 mm2 by day 42 (as compared with 100% incidence on day 21 in non-estrogen-supplemented mice inoculated with MDA-SA (n=8) with osteolytic lesion area of 10.7±2.0 mm2). However, histologic assessment of hind limbs of MCF-7 tumor bearing mice suggested that this estrogen dose stimulated a significant increase in bone mass. Therefore, the estrogen-dependency of bone metastasis formation and changes in BMD were explored. Bone metastasis incidence was estrogen-dependent; falling to less than 100% in mice with E2 doses less than 0.72 mg (50-75%, n = 4-12). BMD of distal femurs of mice supplemented with estradiol was significantly greater than naïve controls on day 28 (average increase of 65.3%, p&lt;0.05), and was not dose dependent over the range of doses tested (0.05-0.72 mg pellets).

Conclusion: Despite a marked increase in bone density, ER+ MCF-7 cells formed radiographically detectable osteolytic lesions with 100% incidence by day 28 in 0.72 mg 60-day 17β- E2 supplemented nude mice. It is possible that estrogen-stimulated increases in BMD contributed to the longer time required to achieve ER+ osteolytic lesion sizes comparable to those in standard ER- models. However, lower doses did not mitigate effects of estrogen on BMD in these 1-month-old mice, while lowering the incidence of bone metastasis formation. While further optimization is planned, intracardiac inoculation of MCF-7 cells in female nude mice provides a robust model of estrogen-dependent ER+ breast cancer bone metastases.

Source of Research Support:

R01 CA174926-01

R03 CA181893-01.

Citation Format: Cheng JN, Frye JB, Whitman SA, Kunihiro AG, Funk JL. Characterization of an estrogen-dependent murine model of human estrogen receptor-positive breast cancer bone metastasis [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-06-08.

Abstract P6-18-01: Site-specific activation of curcuminoids in the breast cancer bone metastases microenvironment

The majority of women with advanced breast cancer (BCa) develop incurable osteolytic bone metastases. Our laboratory has previously demonstrated that curcuminoids, bioactive compounds isolated from turmeric rhizomes, prevent the development of lytic bone lesions in a murine xenograft model of human BCa bone metastasis and inhibit tumor cell secretion of TGFβ-stimulated parathyroid-related protein (PTHrP), a signaling pathway known to drive bone metastasis progression. In both humans and mice, glucuronidated phase II metabolites of curcumin, which are thought to be biologically inactive, are the primary form detected in circulation after consuming curcuminoid-containing foods or supplements. This has led to an untested postulate that curcuminoids may be deglucuronidated at sites of action to form bioactive, aglycone (free) curcumin. Studies were therefore undertaken to test this hypothesis in the context of the murine BCa bone metastasis model, assessing site-specific deconjugation of curcuminoids in the tumor-bone microenvironment.

Effects of curcumin-glucuronide (G-CURC) vs. curcumin (CURC) on TGFβ-stimulated PTHrP secretion by bone-tropic MDA-MB-231 (MDA) cells was determined by immunoradiometric assay. G-CURC and CURC levels were quantified by LC-MS in plasma and bone marrow specimens isolated from curcuminoid-treated female nude mice. Endogenous β-glucuronidase enzyme expression was localized by immunohistochemical (IHC) staining in paraffin-embedded sections of decalcified, MDA metastases-containing hind limbs of nude mice inoculated, via intracardiac injection 21 days prior, with MDA cells. Glucuronide deconjugation activity of bone marrow lysates was determined by colorimetric assay.

In contrast to the inhibitory effects of a naturally occurring curcuminoid mixture or pure CURC, G-CURC did not alter TGFβ-stimulated PTHrP secretion, confirming its postulated lack of biologic activity. In mice treated with curcuminoids, the majority of circulating curcumin was conjugated (91%). In contrast, the majority of curcumin in the bone marrow (56%) was unconjugated free (aglycone) curcumin (p &lt;0.01). IHC staining of MDA tumor-bearing hind limbs of nude mice demonstrated expression of β-glucuronidase (GUSB), an enzyme that deconjugates compounds in mice and humans, by bone marrow cells, but not by tumor cells. Consistent with IHC, bone marrow from female nude mice displayed significantly higher (30-fold) deconjugation enzyme activity compared to MDA cells (p &lt; 0.01). Female C3H/HeJ mice, which possess a partial loss-of-function mutation in the GUSB gene, had significantly decreased (66% lower) deconjugation enzyme activity compared to normal female C57BL/6 (p &lt; 0.001) or nude (p &lt; 0.01) mice. In addition, treatment with the β-glucuronidase inhibitor, saccharolactone (SL), also decreased deconjugation enzyme activity in marrow lysates from female nude mice.

These results suggest that curcuminoids, in the setting of breast cancer bone metastases, may act as a pro-drug, becoming activated within the tumor-bone microenvironment by glucuronidase-expressing hematopoietic bone marrow cells, to limit the progression of osteolytic lesion formation in a murine model of BCa bone metastasis.

Supported by: R01CA174926-01, R01AT006896, and R03CA159382.

Citation Format: Kunihiro AG, Frye JB, Brickey JA, Luis PB, Schneider C, Funk JL. Site-specific activation of curcuminoids in the breast cancer bone metastases microenvironment [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-18-01.

Anti-Inflammatory Effects of the Essential Oils of Ginger (Zingiber officinale Roscoe) in Experimental Rheumatoid Arthritis

Ginger and its extracts have been used traditionally as anti-inflammatory remedies, with a particular focus on the medicinal properties of its phenolic secondary metabolites, the gingerols. Consistent with these uses, potent anti-arthritic effects of gingerol-containing extracts were previously demonstrated by our laboratory using an experimental model of rheumatoid arthritis, streptococcal cell wall (SCW)-induced arthritis. In this study, anti-inflammatory effects of ginger's other secondary metabolites, the essential oils (GEO), which contain terpenes with reported phytoestrogenic activity, were assessed in female Lewis rats with SCW-induced arthritis. GEO (28 mg/kg/d ip) prevented chronic joint inflammation, but altered neither the initial acute phase of joint swelling nor granuloma formation at sites of SCW deposition in liver. Pharmacologic doses of 17-β estradiol (200 or 600 μg/kg/d sc) elicited the same pattern of anti-inflammatory activity, suggesting that GEO could be acting as a phytoestrogen. However, contrary to this hypothesis, GEO had no in vivo effect on classic estrogen target organs, such as uterus or bone. En toto, these results suggest that ginger's anti-inflammatory properties are not limited to the frequently studied phenolics, but may be attributable to the combined effects of both secondary metabolites, the pungent-tasting gingerols and as well as its aromatic essential oils.

Curcuminoids limit neutrophil-mediated reperfusion injury in experimental stroke by targeting the endothelium

OBJECTIVE

We sought to test the hypothesis that turmeric-derived curcuminoids limit reperfusion brain injury in an experimental model of stroke via blockade of early microvascular inflammation during reperfusion.

METHODS

Male Sprague Dawley rats subjected to MCAO/R were treated with turmeric-derived curcuminoids (vs. vehicle) 1 hour prior to reperfusion (300 mg/kg ip). Neutrophil adhesion to the cerebral microcirculation and measures of neutrophil and endothelial activation were assayed during early reperfusion (0-4 hours); cerebral infarct size, edema, and neurological function were assessed at 24 hours. Curcuminoid effects on TNFα-stimulated human brain microvascular endothelial cell (HBMVEC) were assessed.

RESULTS

Early during reperfusion following MCAO, curcuminoid treatment decreased neutrophil rolling and adhesion to the cerebrovascular endothelium by 76% and 67% and prevented >50% of the fall in shear rate. The increased number and activation state (CD11b and ROS) of neutrophils were unchanged by curcuminoid treatment, while increased cerebral expression of TNFα and ICAM-1, a marker of endothelial activation, were blocked by >30%. Curcuminoids inhibited NF-κB activation and subsequent ICAM-1 gene expression in HBMVEC.

CONCLUSION

Turmeric-derived curcuminoids limit reperfusion injury in stroke by preventing neutrophil adhesion to the cerebrovascular microcirculation and improving shear rate by targeting the endothelium.

Curcuminoids block TGF-β signaling in human breast cancer cells and limit osteolysis in a murine model of breast cancer bone metastasis

Effects of curcuminoids on breast cancer cell secretion of the bone-resorptive peptide parathyroid hormone-related protein (PTHrP) and on lytic breast cancer bone metastasis were evaluated. In vitro, transforming growth factor (TGF)-β-stimulated PTHrP secretion was inhibited by curcuminoids (IC50 = 24 μM) in MDA-MB-231 human breast cancer cells independent of effects on cell growth inhibition. Effects on TGF-β signaling revealed decreases in phospho-Smad2/3 and Ets-1 protein levels with no effect on p-38 MAPK-mediated TGF-β signaling. In vivo, mice were inoculated with MDA-MB-231 cells into the left cardiac ventricle and treated ip every other day with curcuminoids (25 or 50 mg/kg) for 21 days. Osteolytic bone lesion area was reduced up to 51% (p < 0.01). Consistent with specific effects on bone osteolysis, osteoclast number at the bone-tumor interface was reduced up to 53% (p < 0.05), while tumor area within bone was unaltered. In a separate study, tumor mass in orthotopic mammary xenografts was also unaltered by treatment. These data suggest that curcuminoids prevent TGF-β induction of PTHrP and reduce osteolytic bone destruction by blockade of Smad signaling in breast cancer cells.

Bioactivity of turmeric-derived curcuminoids and related metabolites in breast cancer

While the chemotherapeutic effect of curcumin, one of three major curcuminoids derived from turmeric, has been reported, largely unexplored are the effects of complex turmeric extracts more analogous to traditional medicinal preparations, as well as the relative importance of the three curcuminoids and their metabolites as anti-cancer agents. These studies document the pharmacodynamic effects of chemically-complex turmeric extracts relative to curcuminoids on human breast cancer cell growth and tumor cell secretion of parathyroid hormone-related protein (PTHrP), an important driver of cancer bone metastasis. Finally, relative effects of structurallyrelated metabolites of curcuminoids were assessed on the same endpoints. We report that 3 curcuminoid-containing turmeric extracts differing with respect to the inclusion of additional naturally occurring chemicals (essential oils and/or polar compounds) were equipotent in inhibiting human breast cancer MDA-MB-231 cell growth (IC50=10-16µg/mL) and secretion of osteolytic PTHrP (IC50=2-3µg/mL) when concentrations were normalized to curcuminoid content. Moreover, these effects were curcuminoid-specific, as botanically-related gingerol containing extracts had no effect. While curcumin and bis-demethoxycurcumin were equipotent to each other and to the naturally occurring curcuminoid mixture (IC50=58µM), demethoxycurcumin did not have any effect on cell growth. However, each of the individual curcuminoids inhibited PTHrP secretion (IC50=22-31µM) to the same degree as the curcuminoid mixture (IC50=16µM). Degradative curcuminoid metabolites (vanillin and ferulic acid) did not inhibit cell growth or PTHrP, while reduced metabolites (tetrahydrocurcuminoids) had inhibitory effects on cell growth and PTHrP secretion but only at concentrations ≥10-fold higher than the curcuminoids. These studies emphasize the structural and biological importance of curcuminoids in the anti-breast cancer effects of turmeric and contradict recent assertions that certain of the curcuminoid metabolites studied here mediate these anti-cancer effects.

Modeling perimenopause in Sprague-Dawley rats by chemical manipulation of the transition to ovarian failure

Various age-related diseases increase in incidence during perimenopause. However, our understanding of the effects of aging compared with hormonal changes of perimenopause in mediating these disease risks is incomplete, in part due to the lack of an experimental perimenopause model. We therefore aimed to determine whether manipulation of the transition to ovarian failure in rats via the use of 4-vinylcyclohexene diepoxide (VCD) could be used to model and accelerate hormonal changes characteristic of perimenopause. We examined long-term (11 to 20 mo), dose-dependent effects of VCD on reproductive function in 1- and 3-mo-old female Sprague-Dawley rats. Twenty-five daily doses of VCD (80 or 160 mg/kg daily compared with vehicle alone) depleted ovarian follicles in a dose-dependent fashion in rats of both ages, accelerated the onset of acyclicity, and caused dose-dependent increases in follicle-stimulating hormone that exceeded those naturally occurring with age in control rats but left serum levels of 17β-estradiol unchanged, with continued ovarian production of androstenedione. High-dose VCD caused considerable nonovarian toxicities in 3-mo-old Sprague-Dawley rats, making this an unsuitable model. In contrast, 1-mo-old rats had more robust dose-dependent increases in follicle-stimulating hormone without evidence of systemic toxicity in response to either VCD dose. Because perimenopause is characterized by an increase in follicle-stimulating hormone with continued secretion of ovarian steroids, VCD acceleration of an analogous hormonal milieu in 1-mo-old Sprague-Dawley rats may be useful for probing the hormonal effects of perimenopause on age-related disease risk.

Decreased bone mineral density in rats rendered follicle-deplete by an ovotoxic chemical correlates with changes in follicle-stimulating hormone and inhibin A

Bone loss during perimenopause, an estrogen-sufficient period, correlates with elevated serum follicle-stimulating hormone (FSH) and decreased inhibins A and B. Utilizing a recently described ovotoxin-induced animal model of perimenopause characterized by a prolonged estrogen-replete period of elevated FSH, we examined longitudinal changes in bone mineral density (BMD) and their association with FSH. Additionally, serum inhibin levels were assessed to determine whether elevated FSH occurred secondary to decreased ovarian inhibin production and, if so, whether inhibins also correlated with BMD. BMD of the distal femur was assessed using dual-energy X-ray absorptiometry (DXA) over 19 months in Sprague-Dawley rats treated at 1 month with vehicle or 4-vinylcyclohexene diepoxide (VCD, 80 or 160 mg/kg daily). Serum FSH, inhibins A and B, and 17-ß estradiol (E(2)) were assayed and estrus cyclicity was assessed. VCD caused dose-dependent increases in FSH that exceeded values occurring with natural senescence, hastening the onset and prolonging the duration of persistent estrus, an acyclic but E(2)-replete period. VCD decreased serum inhibins A and B, which were inversely correlated with FSH (r(2) = 0.30 and 0.12, respectively). In VCD rats, significant decreases in BMD (5-13%) occurred during periods of increased FSH and decreased inhibins, while BMD was unchanged in controls. In skeletally mature rats, FSH (r(2) = 0.13) and inhibin A (r(2) = 0.15) correlated with BMD, while inhibin B and E(2) did not. Thus, for the first time, both the hormonal milieu of perimenopause and the association of dynamic perimenopausal changes in FSH and inhibin A with decreased BMD have been reproduced in an animal model.

Exaggerated neutrophil-mediated reperfusion injury after ischemic stroke in a rodent model of type 2 diabetes

OBJECTIVE

We tested the hypothesis that both chronic and acute inflammatory processes contribute to worse reperfusion injury and stroke outcome in an experimental model of T2DM.

MATERIALS AND METHODS

Twelve- to thirteen-week-old male Zucker Diabetic Fatty (ZDF) rats vs. Zucker Lean Controls (ZLC) rats were tested at baseline and after middle cerebral artery occlusion (ischemia) and reperfusion (I-R). Neutrophil adhesion to the cerebral microcirculation, neutrophil expression of CD11b, infarction size, edema, neurologic function, sICAM, and cerebral expression of neutrophil-endothelial inflammatory genes were measured.

RESULTS

At baseline, CD11b and sICAM were significantly increased in ZDF vs. ZLC animals (p < 0.05). After I-R, significantly more neutrophil adhesion and cell aggregates were observed in ZDF vs. ZLC (p < 0.05); infarction size, edema, and neurologic function were significantly worse in ZDF vs. ZLC (p < 0.05). CD11b and sICAM-1 remained significantly increased in ZDFs (p < 0.05), and cerebral expression of IL-1β, GRO/KC, E-selectin, and sICAM were significantly induced in ZDF, but not ZLC groups (p < 0.05) after 2.5 hours of reperfusion.

CONCLUSION

Both sides of the neutrophil-endothelial interface appear to be primed prior to I-R, and remain significantly more activated during I-R in an experimental model of T2DM. Consequently, reperfusion injury appears to play a significant role in poor stroke outcome in T2DM.

Skeletal muscle fat content is inversely associated with bone strength in young girls

Childhood obesity is an established risk factor for metabolic disease. The influence of obesity on bone development, however, remains controversial and may depend on the pattern of regional fat deposition. Therefore, we examined the associations of regional fat compartments of the calf and thigh with weight-bearing bone parameters in girls. Data from 444 girls aged 9 to 12 years from the Jump-In: Building Better Bones study were analyzed. Peripheral quantitative computed tomography (pQCT) was used to assess bone parameters at metaphyseal and diaphyseal sites of the femur and tibia along with subcutaneous adipose tissue (SAT, mm(2) ) and muscle density (mg/cm(3) ), an index of skeletal muscle fat content. As expected, SAT was positively correlated with total-body fat mass (r = 0.87-0.89, p < .001), and muscle density was inversely correlated with total-body fat mass (r = -0.24 to -0.28, p < .001). Multiple linear regression analyses with SAT, muscle density, muscle cross-sectional area, bone length, maturity, and ethnicity as independent variables showed significant associations between muscle density and indices of bone strength at metaphyseal (β = 0.13-0.19, p < .001) and diaphyseal (β = 0.06-0.09, p < .01) regions of the femur and tibia. Associations between SAT and indices of bone strength were nonsignificant at all skeletal sites (β = 0.03-0.05, p > .05), except the distal tibia (β = 0.09, p = .03). In conclusion, skeletal muscle fat content of the calf and thigh is inversely associated with weight-bearing bone strength in young girls.

4-Vinylcyclohexene diepoxide (VCD) inhibits mammary epithelial differentiation and induces fibroadenoma formation in female Sprague Dawley rats

4-Vinylcyclohexene diepoxide (VCD), an occupational chemical that targets ovarian follicles and accelerates ovarian failure in rodents, was used to test the effect of early-onset reproductive senescence on mammary fibroadenoma formation. One-month female Sprague Dawley rats were dosed with VCD (80 mg/kg or 160 mg/kg) and monitored for 22 months for persistent estrus and tumor development. Only high-dose VCD treatment accelerated the onset of persistent estrus relative to controls. However, both doses of VCD accelerated mammary tumor onset by 5 months, increasing incidence to 84% (vs. 38% in controls). Tumor development was independent of time in persistent estrus, 17 β-estradiol, androstenedione and prolactin. Delay in VCD administration until after completion of mammary epithelial differentiation (3 months) did not alter tumor formation despite acceleration of ovarian senescence. VCD administration to 1-month rats acutely decreased mammary alveolar bud number and expression of β-casein, suggesting that VCD's tumorigenic effect requires exposure during mammary epithelial differentiation.

Protection of trabecular bone in ovariectomized rats by turmeric (Curcuma longa L.) is dependent on extract composition

Extracts prepared from turmeric (Curcuma longa L., [Zingiberaceae]) containing bioactive phenolic curcuminoids were evaluated for bone-protective effects in a hypogonadal rat model of postmenopausal osteoporosis. Three-month female Sprague-Dawley rats were ovariectomized (OVX) and treated with a chemically complex turmeric fraction (41% curcuminoids by weight) or a curcuminoid-enriched turmeric fraction (94% curcuminoids by weight), both dosed at 60 mg/kg 3x per week, or vehicle alone. Effects of two months of treatment on OVX-induced bone loss were followed prospectively by serial assessment of bone mineral density (BMD) of the distal femur using dual-energy X-ray absorptiometry (DXA), while treatment effects on trabecular bone microarchitecture were assessed at two months by microcomputerized tomography (microCT). Chemically complex turmeric did not prevent bone loss, however, the curcuminoid-enriched turmeric prevented up to 50% of OVX-induced loss of trabecular bone and also preserved the number and connectedness of the strut-like trabeculae. These results suggest that turmeric may have bone-protective effects but that extract composition is a critical factor.

Retaining Residual Ovarian Tissue following Ovarian Failure Has Limited Influence on Bone Loss in Aged Mice

Previous work showed that retaining residual ovarian tissue protects young mice from accelerated bone loss following ovarian failure. The present study was designed to determine whether this protection is also present in aged animals. Aged (9-12 months) C57BL/6Hsd female mice were divided into: CON (vehicle), VCD (160 mg/kg; 15d), or OVX (ovariectomized). Lumbar BMD was monitored by DXA and μCT used to assess vertebral microarchitecture. BMD was not different between VCD and CON at any time point but was lower (P < .05) than baseline, starting 1 month after ovarian failure in VCD and OVX mice. Following μCT analysis there were no differences between CON and VCD, but OVX mice had lower bone volume fraction, trabecular thickness, and a trend for decreased connectivity density. These findings provide evidence that retention of residual ovarian tissue may protect aged follicle-depleted mice from accelerated bone loss to a lesser extent than that observed in young mice.

Anti-arthritic effects and toxicity of the essential oils of turmeric (Curcuma longa L.)

Turmeric (Curcuma longa L., Zingiberaceae) rhizomes contain two classes of secondary metabolites, curcuminoids and the less well-studied essential oils. Having previously identified potent anti-arthritic effects of the curcuminoids in turmeric extracts in an animal model of rheumatoid arthritis (RA), studies were undertaken to determine whether the turmeric essential oils (TEO) were also joint protective using the same experimental model. Crude or refined TEO extracts dramatically inhibited joint swelling (90-100% inhibition) in female rats with streptococcal cell wall (SCW)-induced arthritis when extracts were administered via intraperitoneal injection to maximize uniform delivery. However, this anti-arthritic effect was accompanied by significant morbidity and mortality. Oral administration of a 20-fold higher dose TEO was nontoxic, but only mildly joint-protective (20% inhibition). These results do not support the isolated use of TEO for arthritis treatment but, instead, identify potential safety concerns in vertebrates exposed to TEO.