Markers of bone metabolism and overall survival in men with bone-metastatic hormone sensitive prostate cancer (HSPC): A subset analysis of SWOG S1216, a phase III trial of androgen deprivation with or without orteronel

BACKGROUND

Circulating biomarkers of bone metabolism are significantly associated with overall survival (OS) in men with advanced prostate cancer. In the SWOG S1216 phase III trial, we showed that elevated bone biomarkers are significantly associated with an increased risk of death in hormone-sensitive prostate cancer (HSPC) regardless of the status of bone metastases, identifying three risk groups with differential OS outcomes based on bone biomarker status. Here we report the association of bone biomarkers with OS in men with HSPC and documented skeletal metastases as part of a planned subset analysis of S1216.

METHODS

Bone resorption [C-telopeptide (CTx); Pyridinoline (PYD)] and bone formation markers [C-terminal collagen propeptide (CICP); bone alkaline phosphatase (BAP)] were assessed in blood from men with bone metastatic HSPC. Patients were randomly divided into training (n = 238) and validation (n = 475) sets. In the training set, recursive partitioning that maximizes discrimination of OS was used to identify the dichotomous cut-point for each biomarker and for a combination of biomarker split points to define prognostic groups. In the validation set, Cox proportional hazards models were used to assess the impact of biomarkers on OS, adjusted for patient and tumor characteristics.

RESULTS

Of 1279 men, 713 had both baseline bone metastases and evaluable bone biomarkers. Patient characteristics were similar between the overall population and the subset with bone metastases. Elevated levels of CICP, CTX, and PYD were strongly prognostic for OS. Hazard ratios (95% CI) for OS adjusted for treatment arm and baseline clinical variables were: BAP-1.31 (0.93, 1.84), p = 0.12; CICP-1.58 (1.09, 2.29), p < 0.02; CTx - 1.55 (1.12, 2.15), p = 0.008; and PYD-1.66 (1.27, 2.217), p = 0.0002. There was no evidence of interaction between elevated biomarkers and treatment (all p > 0.2). Recursive partitioning algorithms identified four groups of patients with differential OS outcomes based on bone biomarkers, adjusted for baseline clinical variables, with median OS ranging from 2.3 years (highest risk group) to 7.5 years (lowest risk group).

CONCLUSIONS

In this planned S1216 subset analysis of men with HSPC and bone metastases, elevated serum markers of bone metabolism were significantly associated with worse OS. Bone biomarker levels alone and in combination with patient and tumor characteristics identify unique subsets of men with differential OS outcomes.

CLINICALTRIALS

GOV IDENTIFIER

NCT01809691.

Bone Biomarkers and Subsequent Survival in Men with Hormone-sensitive Prostate Cancer: Results from the SWOG S1216 Phase 3 Trial of Androgen Deprivation Therapy with or Without Orteronel

BACKGROUND

Bone biomarkers are strongly prognostic for overall survival (OS) in men with castration-resistant prostate cancer but not fully established for hormone-sensitive prostate cancer (HSPC).

OBJECTIVE

Bone biomarkers in HSPC were prospectively evaluated as part of a phase 3 study of androgen deprivation therapy ± the CYP17 inhibitor orteronel.

DESIGN, SETTING, AND PARTICIPANTS

Patients were randomly divided into training (n = 316) and validation (n = 633) sets. Recursive partitioning and Cox proportional hazard models were employed.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Bone resorption (C-telopeptide and pyridinoline) and bone formation markers (C-terminal collagen propeptide and bone alkaline phosphatase) were assessed from patient sera.

RESULTS AND LIMITATIONS

Of 1279 men, 949 had evaluable baseline bone biomarkers. Optimal cutoffs were identified to define elevated levels of each of the four biomarkers (all p < 0.05) that were associated with worse OS. After adjusting for clinical risk factors in the validation set, elevated bone biomarkers were statistically significantly associated with an increased risk of death (hazard ratios ranging from 1.37 to 1.92). Recursive partitioning algorithms applied to the training set identified three risk groups (low, intermediate, and poor) with differential OS outcomes (median OS: 8.2, 5.1, and 2.1 yr, respectively) based on combinations of bone biomarkers. These results were confirmed in the validation set.

CONCLUSIONS

In men with HSPC initiating androgen deprivation therapy, bone biomarkers are strongly and independently prognostic for OS. Bone biomarker levels alone or in combination with clinical covariates identify unique subsets of men with differential OS outcomes. These results validate the clinical value of bone biomarker assessment in the HSPC state, extending bone biomarker utility beyond the castration-resistant state.

PATIENT SUMMARY

In men with newly diagnosed metastatic prostate cancer, high levels of bone turnover biomarkers are associated with a shorter lifespan.

Altered macronutrient composition and genetics influence the complex transcriptional network associated with adiposity in the Collaborative Cross

Background

Obesity is a serious disease with a complex etiology characterized by overaccumulation of adiposity resulting in detrimental health outcomes. Given the liver’s critical role in the biological processes that attenuate adiposity accumulation, elucidating the influence of genetics and dietary patterns on hepatic gene expression is fundamental for improving methods of obesity prevention and treatment. To determine how genetics and diet impact obesity development, mice from 22 strains of the genetically diverse recombinant inbred Collaborative Cross (CC) mouse panel were challenged to either a high-protein or high-fat high-sucrose diet, followed by extensive phenotyping and analysis of hepatic gene expression.

Results

Over 1000 genes differentially expressed by perturbed dietary macronutrient composition were enriched for biological processes related to metabolic pathways. Additionally, over 9000 genes were differentially expressed by strain and enriched for biological process involved in cell adhesion and signaling. Weighted gene co-expression network analysis identified multiple gene clusters (modules) associated with body fat % whose average expression levels were influenced by both dietary macronutrient composition and genetics. Each module was enriched for distinct types of biological functions.

Conclusions

Genetic background affected hepatic gene expression in the CC overall, but diet macronutrient differences also altered expression of a specific subset of genes. Changes in macronutrient composition altered gene expression related to metabolic processes, while genetic background heavily influenced a broad range of cellular functions and processes irrespective of adiposity. Understanding the individual role of macronutrient composition, genetics, and their interaction is critical to developing therapeutic strategies and policy recommendations for precision nutrition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12263-022-00714-x.

Bone biomarkers and overall survival (OS) in men with advanced hormone-sensitive prostate cancer (HSPC): Results from SWOG S1216, a phase III trial of ADT +/- orteronel

5071

Background: Circulating bone biomarkers (BB) are strongly prognostic for OS in castration-resistant PC (CRPC). We prospectively evaluated BB in men with HSPC in S1216, a trial that established new OS benchmarks. We sought to identify patient (pt) subsets with differential OS outcomes as defined by BB. Methods: Markers of bone resorption [CTx;PYD] & formation [CICP;BAP] were assessed. Pts were randomly divided into training (1/3) & validation (2/3) sets. In the training set, recursive partitioning of OS was used to identify the ideal dichotomous cutpoint for each BB & for a combination of biomarker split points to define prognostic groups. In the validation set, Cox PH models were used to assess impact of BB on OS, adjusted for pt & tumor characteristics. Adjusted odds ratios for 3-year OS based on BB & baseline clinical factors were developed using logistic regression to estimate receiver operating characteristic (ROC) curves. Results: Of 1,279 men, 949 had baseline BB. Median age–68y; median PSA-28 ng/dL; Gleason>7: 60%; Zubrod PS 0/1-97%. Values of BB at the median & at cutpoints maximized for OS were identified. For 3 of the BB, the cutpoint was at the ̃85th %ile; for PYD it was at the median. Recursive partitioning algorithms applied to the training set identified 4 groups with differential OS based on a dichotomous split of CTx in combination with additional CICP splits within each group. Hazard ratios (HR) for OS based on elevated BBs are shown. ROC analysis showed that only BAP & PYD had significantly higher AUC(0.73;0.74) compared to AUC of baseline clinical factors(0.71) w/ p=0.02 and 0.03 respectively. There was no evidence of BB x treatment interaction (all p>=0.2). Conclusions: In men initiating ADT for HSPC, elevated BB are strongly prognostic for worse OS. BB levels alone & in combination with pt/tumor characteristics identify unique subsets of men with high probability of being alive at 3 years from ADT initiation. These results validate the clinical value of BB in the HSPC state, extending BB utility beyond CRPC. Clinical trial information: NCT01809691. [Table: see text]

High-fat diet-induced colonocyte dysfunction escalates microbiota-derived trimethylamine N-oxide

A Western-style, high-fat diet promotes cardiovascular disease, in part because it is rich in choline, which is converted to trimethylamine (TMA) by the gut microbiota. However, whether diet-induced changes in intestinal physiology can alter the metabolic capacity of the microbiota remains unknown. Using a mouse model of diet-induced obesity, we show that chronic exposure to a high-fat diet escalates Escherichia coli choline catabolism by altering intestinal epithelial physiology. A high-fat diet impaired the bioenergetics of mitochondria in the colonic epithelium to increase the luminal bioavailability of oxygen and nitrate, thereby intensifying respiration-dependent choline catabolism of E. coli In turn, E. coli choline catabolism increased levels of circulating trimethlamine N-oxide, which is a potentially harmful metabolite generated by gut microbiota.

Assessment of FMO3 SNPs in Relation to TMAO in Generally Healthy United States Adults

Objectives

The hepatic enzyme flavin monooxygenase 3 (FMO3) oxidizes many metabolites including trimethylamine to the atherogenic molecule trimethylamine n-oxide (TMAO). Variants in the open reading frame of the FMO3 gene alter the enzyme's activity; therefore, we genotyped two a priori missense FMO3 SNPs in a cohort of unmedicated healthy adults. We hypothesized that the SNPs might affect the activity of the encoded enzyme leading to reductions in circulating TMAO. FMO3 expression is upregulated by estrogen, thus we also assessed the relationship of the SNPs and TMAO in pre- and postmenopausal women.

Methods

DNA was extracted from whole blood from 349 subjects (182 women) who were enrolled in a cross-sectional study at the USDA/ARS WHNRC. SNPs rs2266782 (G &gt; A, p.Glu158Lys) and rs2266780 (A &gt; G, p.Glu308Gly) were genotyped using TaqMan SNP genotyping kits and PCR. TMAO was purified from fasted plasma and quantified using high resolution LC-MS. Regression models were built to assess the relationship of the SNPs to TMAO in the full cohort and by self-reported menopausal status in women. Models assessing the full cohort were adjusted for plasma cystatin C and a sex*age interaction, whereas the menopausal analysis was adjusted for cystatin C.

Results

The cohort's minor allele frequencies were 36.5% and 17.5% for SNPs rs2266782 and rs2266780, respectively, which were consistent with the genome aggregation exome reports. For both SNPs, median TMAO concentrations increased in individuals carrying the risk alleles, however the differences by genotypes were not significant. In women, the AA genotype at rs2266780 was associated with reduced TMAO levels in pre-, but not postmenopausal women (P = 0.01). This effect was not identified in females with AG or GG genotypes, regardless of their menopausal state.

Conclusions

Effects of the evaluated FMO3 SNPs on TMAO levels were not identified in the full cohort. However, the SNP rs2266780 was associated with reduced TMAO in premenopausal women with the AA genotype but not women with the AG or GG genotypes, nor those who were postmenopausal. This finding reinforces previous observations that risks for cardiovascular diseases increase after menopause in women.

Funding Sources

The Beef Checkoff, R01HL128572; USDA-ARS 2032–53,000–001–00-D, 2032–51,530–022–00-D, and 2032–51,000-004–00D; NCATS NIH UL1 TR001860.

Sexual Dimorphism of Atherosclerosis by Gut Microbiome in a Hyperlipidemic Diversity Outbred F1 Mouse Population

Objectives

Atherosclerosis is a complex multifactorial disease that develops through the interaction of various genetic and environmental factors. The environmental factors affecting atherosclerosis susceptibility include gender differences and the gut microbiota. However, the association between sex, microbiota, and atherosclerosis remains unclear. We hypothesized that the association between gut microbial profiles and atherosclerosis demonstrates sexual dimorphism. In order to test this hypothesis, we examined atherosclerosis and microbiota in a population of hyperlipidemic outbred mice.

Methods

We collected offspring (262 female and 269 male mice) from a cross between hyperlipidemic male C57BL/6J mice, transgenic for both human apolipoprotein E-Leiden and cholesterol ester transfer protein genes, and ∼200 female Diversity Outbred (DO) mice, a population derived from 8 inbred strains. We fed the offspring a high fat/cholesterol diet for 12 weeks. We then examined over 20 cardio-metabolic traits and their fecal microbiota compositions using 16S rRNA sequencing.

Results

Female mice were significantly more susceptible to atherosclerosis with higher lesion area (P &lt; 0.0001) and plasma cholesterol (P &lt; 0.0001) than males. For gut microbiota analysis, females had higher microbial α-diversity (Shannon diversity, P &lt; 0.0001) than males and their β-diversity (Unweighted UniFrac, R2 = 0.01, PERMANOVA &lt; 0.001) showed that the overall community is significantly different. We also examined the association between sexually-dimorphic gut phylotypes and cardiometabolic phenotypes and identified a negative correlation between atherosclerosis and the abundance of the genus Bifidobacterium, while abundances of genus Lactococcus were positively associated with atherosclerosis. Upcoming studies will be designed to identify host genes affecting microbiota abundance and functional characterization of specific microbiota-atherosclerosis traits.

Conclusions

To the best of our knowledge, this study suggests the first example of complex interactions between sexually dimorphic traits and gut microbiota associated with atherosclerosis using DO-F1 mice.

Funding Sources

This work was supported by the National Heart, Lung, and Blood Institute.

Trimethylamine-N-Oxide (TMAO) Is Not Associated with Average Daily Intake of Red Meat or TMAO-Precursor Foods in a Generally Healthy Population

Objectives

The microbial metabolite trimethylamine n-oxide (TMAO) is associated with cardiovascular and renal disease. The dietary factors contributing to plasma TMAO concentrations are not well characterized in a generally healthy population unmedicated for metabolic diseases. The objective of this study was to assess the relationships among TMAO-precursor foods, TMAO, and classic cardiometabolic markers in a generally healthy population stratified for age, sex, and BMI.

Methods

Fasting plasma TMAO was quantified using liquid chromatography-mass spectrometry in 356 participants (n = 188 female, 18–65 yr, 18–40 BMI) enrolled in the cross-sectional Nutritional Phenotyping Study conducted as the USDA Western Human Nutrition Center. Diet was assessed by averaging 2 weekday and 1 weekend ASA-24hr recalls cleaned by NCBI guidelines. Fasting plasma analytes such as glucose, insulin, triglycerides, and cholesterol were measured using the Cobas Integra 400 Plus. Variables were transformed to conform to the normal distribution. Regression models assessing health parameters and TMAO were adjusted for age, sex, and the kidney function marker, cystatin C. Models assessing TMAO and diet variables were adjusted for age, sex, and energy intake. Composite variables describing average intake of red meat and TMAO-precursor foods were created by summing the appropriate ASA24 variables.

Results

TMAO was associated with age (P = 0.001), but not sex or BMI. A significant interaction (P = 0.006) between sex and age was used in all models. Of the variables analyzed, only refined grains and total energy intake were significantly associated with TMAO (r = −0.11, P = 0.04; r = 0.12, P = 0.03, respectively). Reduced renal function as assessed by circulating cystatin C concentrations was associated with plasma TMAO (r = 0.18, P &lt; 0.001). Average daily red meat consumption as well as average daily TMAO-precursor consumption was not significantly associated with TMAO (P = 0.137, P = 0.554, respectively). In contrast, average daily fiber intake was marginally related to TMAO (B = −0.11, SE = 0.01, P = 0.07).

Conclusions

In this generally healthy population, no relationship between red meat or TMAO-precursor foods and TMAO was identified.

Funding Sources

The Beef Checkoff (R01HL128572); USDA/ARS/Western Human Nutrition Research Center project funds (2032–51,000-025–00D).

Bone metabolism biomarkers (BMB) and progression-free survival (PFS) in men with metastatic hormone-sensitive prostate cancer (HSPC): SWOG S1216, a phase III trial of androgen deprivation therapy (ADT) with or without orteronel

5523

Background: We previously reported that baseline BMB are independently prognostic for overall survival (OS) in men with castration resistant prostate cancer. We correlated BMB with outcomes in mHSPC as part of S1216, a phase III trial of ADT +/- the novel CYP17 inhibitor orteronel. Methods: Blood was obtained at study entry for bone resorption [C-telopeptide(CTx) & Pyridinoline(PYD)] & formation markers [C-terminal collagen propeptide(CICP) & bone alkaline phosphatase(BAP)]. With prior DSMC approval, patients were sampled to mask potential treatment effect. Logistic regression was used to assess if BMB elevation above median was prognostic for a PFS event w/in 2 years across pooled study treatment arms, adjusting for baseline variables (including disease extent, PSA, age, pre-randomization ADT, & presence of bone mets). An additional interaction term between BMB elevation & presence of bone mets was included; if significant, separate models were developed for men +/- bone mets. Results: Of 1,313 men, 656 were included in this analysis. All 4 BMB levels were higher in men with a PFS event w/in 2 years vs. those with no PFS event. The odds ratio (OR) for a PFS event was significantly higher in men w/ elevated baseline BMB (see table). For BAP, a significant interaction between marker elevation and bone mets was seen (p = 0.003); men w/ bone mets and BAP elevation had an OR of 1.83 for a PFS event in 2 years. Conclusions: In men with newly diagnosed HSPC, elevated baseline levels of BMB were significantly associated with PFS, with about a two-fold increased risk of a progression event w/in 2 years. For CICP, CTx, & PYD, this association was independent of the presence of bone metastases. Baseline BMB levels have strong prognostic value in the mHSPC context. Correlative analysis of BMB & OS is planned. Clinical trial information: NCT01809691 . [Table: see text]

A Mediterranean-style Eating Pattern Lower in Lean Red Meat Reduced Plasma Trimethylamine N-Oxide in Adults Classified as Overweight or Obese (P08-030-19)

Objectives

To determine the effect of adopting a Mediterranean-style eating pattern with different quantities of lean unprocessed red meat on the plasma concentration of Trimethylamine N-Oxide (TMAO), an emerging potential cardiovascular disease risk factor, in middle-aged adults classified as overweight or obese.

Methods

Thirty-nine adults (12 males and 27 females; age 46 ±10 years, BMI 30.6 ± 3.6 kg/m2; mean ± SD) participated in a randomized, crossover and controlled feeding trial. Each participant consumed a Mediterranean-style eating pattern for two 5-week intervention periods separated by ∼4 weeks of consuming their unrestricted, self-selected diet (washout). The Mediterranean-style eating pattern contained either a commonly recommended amount of red meat (∼200 g/wk, Med-200) or the average amount consumed in the U.S. (∼500 g/wk, Med-500). Plasma samples were collected before (baseline) and at the end (post) of the two intervention periods and TMAO was measured by stable isotope dilution chromatography tandem mass spectrometry. Geometric means were compared with mixed model tests in SAS.

Results

Baseline TMAO concentrations were not different between interventions (Med-200 = 4.4 ± 2.7 and Med-500 = 5.2 ± 4.5 μM, P = 0.476). These concentrations are similar to values reported in healthy adults. Post-intervention, TMAO was lower in Med-200 vs. Med-500 (3.1 ± 1.2 and 5.0 ± 2.6 μM, P = 0.001).

Conclusions

The 2015–2020 Dietary Guidelines for Americans encourages adopting a Mediterranean-style eating pattern to promote cardiovascular health, including reduced blood pressure and improved lipid-lipoprotein profile. The current results suggest that adopting a Mediterranean-study eating pattern may also reduce the cardiovascular disease risk factor TMAO, but only when it contains a lower, recommended, amount of lean unprocessed red meat. The influences of animal- and plant-based foods consumed with a Mediterranean-style and other healthy eating patterns on emerging cardiovascular disease risk factors remain to be determined. This trial was registered at clinicaltrials.gov as NCT02573129.

Funding Sources

Supported by theBeef Checkoff, the Pork Checkoff, the NIH pre-doctoral training grant 5T32DK076540-08, the NIH-supported Indiana Clinical and Translational Sciences Institute and the USDA-ARS-Western Human Nutrition Research Center.

A Randomized Controlled-feeding Trial Based on the Dietary Guidelines for Americans Does Not Affect Plasma Trimethylamine N-oxide Levels in Women (P08-031-19)

Objectives

Trimethylamine N-oxide is a gut-mediated metabolite associated with cardiovascular disease. Acute diet challenges demonstrate that circulating TMAO concentrations are diet-responsive; however, long-term trials investigating how different dietary patterns affect circulating TMAO concentrations are sparse. The objective of the current study was to determine whether consumption of a diet patterned after the USDA's 2010 Dietary Guidelines for Americans (DGA), as compared to the typical American Diet (TAD), would reduce plasma TMAO levels.

Methods

A randomized, double-blind, controlled 8-wk intervention was conducted in overweight and obese women selected according to indexes of insulin resistance or dyslipidemia. Women were randomly assigned to the DGA or TAD group (n = 28 DGA and 24 TAD). The TAD diet was based on average adult intake from the NHANES 2009–2010. All foods and beverages were provided during the intervention and matched to each participant's energy requirement to ensure maintenance of initial body weight.Plasma samples were collected at baseline, 1 wk of their typical diet, and after 2 and 8 weeks of dietary intervention, in an overnight-fasted condition, and utilized to quantitate circulating TMAO concentrations using stable isotope dilution chromatography tandem mass spectrometry. Statistical analysis were performed in SAS using analysis of covariance and partial correlation.

Results

Following 2 or 8 weeks of dietary intervention, plasma TMAO concentrations were not different between the DGA and TAD diets (3.45 ± 0.41 vs 2.91 ± 0.38 μM at week 2; 3.48 ± 0.41 vs 3.00 ± 0.40 μM at week 8, Mean ± SE, respectively). Post-intervention TMAO concentration was correlated to initial TMAO concentrations and body mass index but not age. Furthermore, we did not observe significant correlations between TMAO and measures of endothelial function (Endopat) or insulin resistance (HOMA-IR) which may reflect the relative health of the overall population enrolled in the study.

Conclusions

Consumption of a diet based on the USDA's 2010 Dietary Guidelines for Americansfor 8 weeks did not reduce plasma TMAO levels in this study.

Funding Sources

Supported by National Dairy Council; Campbell Soup Co.; USDA-ARS Projects 2032-51530-022-00D and 6026-51000-010-05S.

microRNA-146a-5p association with the cardiometabolic disease risk factor TMAO

Trimethylamine-N-oxide (TMAO), a microbial choline metabolism byproduct that is processed in the liver and excreted into circulation, is associated with increased atherosclerotic lesion formation and cardiovascular disease risk. Genetic regulators of TMAO levels are largely unknown. In the present study, we used 288 mice from a genetically heterogeneous mouse population [Diversity Outbred (DO)] to determine hepatic microRNA associations with TMAO in the context of an atherogenic diet. We also validated findings in two additional animal models of atherosclerosis: liver-specific insulin receptor knockout mice fed a chow diet (LIRKO) and African green monkeys fed high-fat/high-cholesterol diet. Small RNA-sequencing analysis in DO mice, LIRKO mice, and African green monkeys identified only one hepatic microRNA (miR-146a-5p) that is aberrantly expressed across all three models. Moreover, miR-146a-5p levels are associated with circulating TMAO after atherogenic diet in each of these models. We also performed high-resolution genetic mapping and identified a novel quantitative trait locus on Chromosome 12 for TMAO levels. This interval includes two genes, Numb and Dlst, which are inversely correlated with both miR-146a and TMAO and are predicted targets of miR-146a. Both of these genes have been validated as direct targets of miR-146a, though in other cellular contexts. This is the first report to our knowledge of a link between miR-146 and TMAO. Our findings suggest that miR-146-5p, as well as one or more genes at the Chromosome 12 QTL (possibly Numb or Dlst), is strongly linked to TMAO levels and likely involved in the control of atherosclerosis.

Bone turnover biomarkers identify unique prognostic risk groups in men with castration resistant prostate cancer and skeletal metastases: Results from SWOG S0421

BACKGROUND

Skeletal metastases often occur in men with castration-resistant prostate cancer (CRPC) where bone biomarkers are prognostic for overall survival (OS). In those with highly elevated markers, there is preferential benefit from bone-targeted therapy. In the phase IIIS0421 docetaxel +/- atrasentan trial, clinical covariates and bone biomarkers were analyzed to identify CRPC subsets with differential outcomes.

SUBJECTS AND METHODS

Markers of bone resorption [N-telopeptide-NTx; pyridinoline-PYD] and formation [C-terminal collagen propeptide-CICP; bone alkaline phosphatase-BAP] were measured in pre-treatment sera. Bone biomarkers and clinical covariates were included in a Cox model for OS; bone markers were added in a stepwise selection process. Receiver operating characteristic (ROC) curves were constructed for risk factor models +/- bone markers. Significant variables were allowed to compete in a classification and regression tree (CART) analysis. Hazard ratios(HR) were calculated by comparing OS in each of the terminal nodes to a reference group in a Cox model.

RESULTS

750 patients were included. Each bone marker significantly contributed to the risk factor-adjusted OS Cox model, with higher levels associated with worse OS. BAP (HR = 1.15, p = 0.008), CICP (HR = 1.27, p < 0.001), and PYD (HR = 1.21, p = 0.047) in combination were significantly associated with OS. Prognostic accuracy was improved by addition of bone markers to clinical covariates. CART analysis selected CICP, BAP, hemoglobin, and pain score for the final OS model, identifying five prognostic groups.

CONCLUSIONS

Elevated serum bone biomarker levels are associated with worse OS in bone-metastatic CRPC. Bone biomarkers can identify unique prognostic subgroups. These results further define the role of bone biomarkers in the design of CRPC trials.

The effects of a lipid-based nutrient supplement and antiretroviral therapy in a randomized controlled trial on iron, copper, and zinc in milk from HIV-infected Malawian mothers and associations with maternal and infant biomarkers

We evaluated effects of antiretroviral (ARV) therapy and lipid‐based nutrient supplements (LNSs) on iron, copper, and zinc in milk of exclusively breastfeeding HIV‐infected Malawian mothers and their correlations with maternal and infant biomarkers. Human milk and blood at 2, 6, and 24 weeks post‐partum and blood during pregnancy (≤30 weeks gestation) were collected from 535 mothers/infant‐pairs in the Breastfeeding, Antiretrovirals, and Nutrition study. The participants received ARV, LNS, ARV and LNS, or no intervention from 0 to 28 weeks post‐partum. ARVs negatively affected copper and zinc milk concentrations, but only at 2 weeks, whereas LNS had no effect. Among all treatment groups, approximately 80–90% of copper and zinc and <50% of iron concentrations met the current adequate intake for infants at 2 weeks and only 1–19% at 24 weeks. Pregnancy haemoglobin was negatively correlated with milk iron at 2 and 6 weeks (r = −.18, p < .02 for both). The associations of the milk minerals with each other were the strongest correlations observed (r = .11–.47, p < .05 for all); none were found with infant biomarkers. At 2 weeks, moderately anaemic women produced milk higher in iron when ferritin was higher or TfR lower. At 6 weeks, higher maternal α‐1‐acid glycoprotein and C‐reactive protein were associated with higher milk minerals in mildly anaemic women. Infant TfR was lower when milk mineral concentrations were higher at 6 weeks and when mothers were moderately anaemic during pregnancy. ARV affects copper and zinc milk concentrations in early lactation, and maternal haemoglobin during pregnancy and lactation could influence the association between milk minerals and maternal and infant iron status and biomarkers of inflammation.

Serum biomarkers of bone metabolism in castration-resistant prostate cancer patients with skeletal metastases: results from SWOG 0421

BACKGROUND

Prior studies suggest that elevated markers of bone turnover are prognostic for poor survival in castration-resistant prostate cancer (CRPC). The predictive role of these markers relative to bone-targeted therapy is unknown. We prospectively evaluated the prognostic and predictive value of bone biomarkers in sera from CRPC patients treated on a placebo-controlled phase III trial of docetaxel with or without the bone targeted endothelin-A receptor antagonist atrasentan (SWOG S0421).

METHODS

Markers for bone resorption (N-telopeptide and pyridinoline) and formation (C-terminal collagen propeptide and bone alkaline phosphatase) were assayed in pretreatment and serial sera. Cox proportional hazards regression models were fit for overall survival. Models were fit with main effects for marker levels and with/without terms for marker-treatment interaction, adjusted for clinical variables, to assess the prognostic and predictive value of atrasentan. Analysis was adjusted for multiple comparisons. Two-sided P values were calculated using the Wald test.

RESULTS

Sera from 778 patients were analyzed. Elevated baseline levels of each of the markers were associated with worse survival (P < .001). Increasing marker levels by week nine of therapy were also associated with subsequent poor survival (P < .001). Patients with the highest marker levels (upper 25th percentile for all markers) not only had a poor prognosis (hazard ratio [HR] = 4.3; 95% confidence interval [CI] = 2.41 to 7.65; P < .001) but also had a survival benefit from atrasentan (HR = 0.33; 95% CI = 0.15 to 0.71; median survival = 13 [atrasentan] vs 5 months [placebo]; P interaction = .005).

CONCLUSIONS

Serum bone metabolism markers have statistically significant independent prognostic value in CRPC. Importantly, a small group of patients (6%) with highly elevated markers of bone turnover appear to preferentially benefit from atrasentan therapy.

SWOG 0421: Prognostic and predictive value of bone metabolism biomarkers (BMB) in castration resistant prostate cancer (CRPC) patients (pts) with skeletal metastases treated with docetaxel (DOC) with or without atrasentan (ATR)

4547

Background: S0421, a phase III study of DOC +/- the endothelin antagonist ATR in CRPC pts with bone metastases, showed no overall survival (OS) benefit for DOC+ATR. While BMB may have a prognostic role in CRPC, their predictive role vis a vis bone-targeted therapy such as ATR is unknown. We prospectively assessed pre-treatment serum BMB from S0421 pts to validate their prognostic and predictive value. Methods: BMB for resorption (N-telopeptide, NTX and Pyridinoline, PYD) and formation (C-terminal collagen propeptide, CICP and bone alkaline phosphatase, BAP) were assayed [Quidel (PYD, CICP, BAP) and Wampole (NTX)]. Cox regression models for OS based on BMB adjusted for clinical variables were developed. An adjusted Cox model was fit with main effects and BMB x Treatment interaction to assess predictive value of ATR on OS. Results: Of 1,038 pts, 855 (82%) submitted baseline serum: 778 (91%) were usable and analyzable. Pt characteristics: median age = 69 years; PS 0-1 = 91%, Bisphosphonate use = 61%; Gleason >7 = 56%; median PSA = 68; and bone mets only = 45%. BMB values (median; range): NTX (14 nM; 9.3-23.9), BAP (64.7 u/L; 35-164), CICP (9.5 ng/mL; 6.5-17.4), and PYD (2.8 nmol/L; 2.2-3.9). Table below shows prognostic role of BMB. Pts with very high BMB (upper 25 %ile, n=47) not only have poor prognosis (HR = 4.3, p<0.001) but have OS benefit from ATR (HR=0.34, median OS = 13.6 vs. 6.7 months; interaction p=0.002**). Conclusions: S0421 validates the strong independent OS prognostic value of BMB in CRPC. Very high BMB levels appear to be significantly predictive of OS benefit with ATR. Further study of endothelin antagonists in CRPC should focus on this high-risk pt subset. (5R01-CA120469) [Table: see text]

Genes encoding Th2 cytokines and other proteins of immunological interest in the Oryctolagus cuniculus (rabbit) whole genome sequence and ENCODE (170.20)

Rabbits, a valuable resource for diagnostic and therapeutic antibodies, are becoming increasingly important for vaccine development, and are used as animal models of human autoimmune, infectious and other diseases. The unique characteristics of their immune system, resulting in antibodies of high affinity and specificity, make them a major source of polyclonal and monoclonal antibodies. Whole genome sequencing (WGS) at 7x coverage and assembly of a high quality draft rabbit genome sequence was recently completed at Broad Institute. The Thorbecke Rabbit (TR) chosen for sequencing was less heterozygous than outbred New Zealand White (NZW), but was heterozygous at the immunoglobulin heavy chain locus. The TR strain was more susceptible to Tuberculosis and had obvious developmental abnormalities. Any follow-up on the biology must use another rabbit strain because the TR strain was lost in a fire. The ENCODE Project, with ~ 1% of rabbit genomic sequence from a different, normal NZW animal, includes genes of immunological interest such as a cluster containing the coordinately regulated Th2 cytokine genes IL5, IL13, and IL4. Cross-species comparative genome analysis revealed conservation of some coding and regulatory sequences within syntenic regions of rabbit and 9 other mammals. A few differences between the coding sequences of one TR and one NZW rabbit, and many differences in regulatory sequences across mammals were found. Other genes of the immune system are now under study.

The content and accessibility of sex education information on the Internet

The objective of this study was to describe Web sites with sex education material and assess the accessibility of specific information on the Internet. First, the authors conducted a review of Web sites using specific sex education keywords. Second, 27 undergraduate students were asked to locate information on proper condom use and sexually transmitted disease (STD) symptoms. The time, number of search attempts, and number of clicks needed to identify each piece of information were recorded. The authors identified 41 sites with sex education material from almost 6 million pages yielded by the keywords. Sixty-three percent of the 1,556 most compatible pages were categorized as pornography. The students found the information on condom use and STD symptoms in an average of 4 minutes, using fewer then six clicks and two searches. The authors concluded that general information on sex education is difficult to locate on the Internet and often lacks essential elements, but accurate and useful information on specific topics can be more easily obtained.

Comparison of myocardial thallium-201 clearance after maximal and submaximal exercise: implications for diagnosis of coronary disease: concise communication

Recently the quantitation of regional thallium-201 clearance has been shown to increase the sensitivity of the scintigraphic detection of coronary disease. Although TI-201 clearance rates might be expected to vary with the degree of exercise, this relationship has not been explored. We therefore evaluated the rate of decrease in myocardial TI-201 activity following maximal and submaximal stress in seven normal subjects and 21 patients with chest pain, using the seven-pinhole tomographic reconstruction technique. In normals, the mean TI-201 clearance rate declined from 41% +/- 7 over a 3-hr period with maximal exercise to 25% +/- 5 after 3 hr at a submaximal level (p less than 0.001). Similar differences in clearance rates were found in the normally perfused regions of the left ventricle in patients with chest pain, depending on whether or not a maximal end point (defined as either the appearance of ischemia or reaching 85% of age-predicted heart rate) was achieved. In five patients who did not reach these end points, 3-hr clearance rates in uninvolved regions averaged 25% +/- 2, in contrast to a mean of 38% +/- 5 for such regions in 15 patients who exercised to ischemia or an adequate heart rate. These findings indicate that clearance criteria derived from normals can be applied to patients who are stressed maximally, even if the duration of exercise is limited, but that caution must be used in interpreting clearance rates in those who do not exercise to an accepted end point.

Coronary atherosclerosis in mitral stenosis

Eighty-two patients with mitral stenosis underwent cardiac catheterization with coronary angiography. Twenty-one patients (26 percent) had coronary artery disease. Characteristics of the mitral valve area, cardiac output, pulmonary artery pressure, pulmonary vascular resistance, left ventricular end-diastolic pressure, left ventricular ejection fraction, and atypical chest pain did not correlate with findings of angina pectoris or of coronary artery disease; however, there was correlation with sex, age, and angina. Coronary artery disease occurred only after the age of 40 years and was more frequent in males with angina. Coronary artery disease could not be ruled out in patients with mitral stenosis, especially those over age 40, without coronary arteriography.

Echocardiographic demonstration of early mitral valve closure in severe aortic insufficiency. Its clinical implications

Severe aortic insufficiency may accelerate mitral valve closure. We noted this echocardiographic finding in several patients with the acute onset of severe aortic insufficiency. Accordingly, we examined our total echocardiographic series retrospectively for early closure of the mitral valve (ECMV) in the setting of aortic insufficiency and found it in 11 of 53 patients with confirmed aortic insufficiency. During our study ECMV was fortuitously found in two other patients without aortic insufficiency, ECMV occurred in late diastole following the echocardiographic "A" wave, often associated with s suppressed "A" wave (type "B" ECMV). ECMV presence and subtype, along with other clinical parameters, appeared to be useful in the serial evaluation of the patient with severe aortic insufficiency. Additionally, the analysis of ECMV type helped to clarify the mechanism and significance of the Austin Flint murmur. Analysis of 17 patients with and without ECMV, with severe aortic insufficiency judged clinically (NYHA functional class III or IV) and angiographically (3+), indicated that only ECMV patients had acute aortic insufficiency and demonstrated diminished left ventricular size following successful aortic valve replacement. Although due primarily to aortic insufficiency, ECMV could be influenced by rhythm or conducted abnormalities, co-existent cardiac lesions, and pharmacologic interventions. Exclusive of these factors, ECMV was an excellent sign of acute, torrential aortic insufficiency, and a simple noninvasive indicator of the patient requiring immediate aortic valve replacement.