An exploratory study of respiratory quotient calibration and association with postmenopausal breast cancer

Short-duration cold exposure decreases fasting-induced glucose intolerance but has no effect on resting energy expenditure

The aim of the present study was to investigate whether brief cold exposure can reverse fasting-induced glucose intolerance and insulin resistance, and improve resting energy expenditure (REE). Twelve young non-obese women were randomly assigned to undergo the following conditions: 2 days of fasting with two 10-min whole-body cold-water immersions on separate days (FAST-COLD), 2 days of fasting without cold-water immersions (FAST), 2 days of usual diet with two 10-min whole-body cold-water immersions on separate days (COLD), or 2 days of usual diet without cold-water immersions (CON) in a randomised crossover fashion. Changes in REE and substrate utilisation, and glucose tolerance and insulin sensitivity from the oral glucose tolerance test were examined. The results showed that FAST-COLD and FAST trials increased (P < 0.05) REE and decreased (P < 0.05) respiratory quotient, but these variables did not differ significantly between the FAST-COLD and FAST trials. The glucose and insulin area under the curves (AUCs) were higher (P < 0.05) in the FAST-COLD and FAST trials than in the CON and COLD trials, and these AUCs were lower (P < 0.05) in the FAST-COLD than in the FAST trial. Matsuda index was lower in the FAST trial than in the CON trial (P < 0.05), and tended to be greater after the FAST-COLD trial than after the FAST trial (P = 0.060). In conclusion, cold exposure had no effect on REE but decreased fasting-induced glucose intolerance which was accompanied by a maintained insulin sensitivity.

Sexual dimorphic metabolic and cognitive responses of C57BL/6 mice to Fisetin or Dasatinib and quercetin cocktail oral treatment

Senolytic treatment in aged mice clears senescent cell burden leading to functional improvements. However, less is known regarding the effects of these compounds when administered prior to significant senescent cell accumulation. From 4-13 months of age, C57BL/6 male and female mice received monthly oral dosing of either 100 mg/kg Fisetin or a 5 mg/kg Dasatinib (D) plus 50 mg/kg Quercetin (Q) cocktail. During treatment, several aspects of healthy aging were assayed including glucose metabolism using an insulin and glucose tolerance test, cognitive performance using Morris water maze and novel object recognition, and energy metabolism using indirect calorimetry. Afterwards, mice were euthanized for plasma, tissue specific markers of senescence-associated secretory phenotype (SASP), and white adipose tissue accumulation (WAT). Sexually dimorphic treatment effects were observed. Fisetin treated male mice had reduced SASP, enhanced glucose and energy metabolism, improved cognitive performance, and increased mRNA expression of adiponectin receptor 1 and glucose transporter 4. D + Q treatment had minimal effects in male C57BL/6 mice, but was detrimental to females causing increased SASP expression along with accumulation of WAT depots. Reduced energy metabolism and cognitive performance were also noted. Fisetin treatment had no effect in female C57BL/6 mice potentially due to a slower rate of biological aging. In summary, the senolytic treatment in young adulthood, has beneficial, negligible, or detrimental effects in C57BL/6 mice dependent upon sex and treatment. These observations should serve as a note of caution in this rapidly evolving and expanding field of investigation. Male and female C57BL/6 mice were treated with once monthly oral doses of either Dasatinib (D) + Quercetin (Q) or Fisetin from 4-13 months of age. Males treated with Fisetin had reduced SASP markers (blue spheres) as well as improved metabolism (red flame) and cognition. Females treated with D + Q had increased adiposity and SASP markers (red spheres) along with decreased metabolism (blue flame) and cognitive performance. No effects were observed in females treated with Fisetin or males treated with D + Q.

Associations of Biomarker-Calibrated Healthy Eating Index-2010 Scores with Chronic Disease Risk and Their Dependency on Energy Intake and Body Mass Index in Postmenopausal Women

BACKGROUND

Prior studies examined associations between the Healthy Eating Index (HEI) and chronic disease risk based on self-reported diet without measurement error correction.

OBJECTIVE

Our objective was to test associations between biomarker calibration of the food-frequency questionnaire (FFQ)-derived HEI-2010 with incident cardiovascular disease (CVD), cancer, and type 2 diabetes (T2D) among Women's Health Initiative (WHI) participants.

METHODS

Data were derived from WHI postmenopausal women (n = 100,374) aged 50-79 y at enrollment (1993-1998) at 40 US clinical centers, linked to nutritional biomarker substudies and outcomes over subsequent decades of follow-up. Baseline or year 1 FFQ-derived HEI-2010 scores were calibrated with nutritional biomarkers and participant characteristics (e.g., BMI) for systematic measurement error correction. Calibrated data were then used in HR models examining associations with incidence of CVD (total, subtypes, mortality), cancer (total, subtypes, mortality), and T2D in WHI participants with approximately 2 decades of follow-up. Models were multivariable-adjusted with further adjustment for BMI and doubly labeled water (DLW)-calibrated energy.

RESULTS

Multivariable-adjusted HRs modeled a 20% increment in HEI-2010 score in relation to outcomes. HRs were modest using uncalibrated HEI-2010 scores (HRs = 0.91-1.09). Using biomarker-calibrated HEI-2010, 20% increments in scores yielded multivariable-adjusted HRs (95% CIs) of 0.75 (0.60, 0.93) for coronary heart disease; 0.75 (0.61, 0.91) for myocardial infarction; 0.96 (0.92, 1.01) for stroke; 0.88 (0.75, 1.02) for CVD mortality; 0.81 (0.70, 0.94) for colorectal cancer; 0.81 (0.74, 0.88) for breast cancer; 0.79 (0.73, 0.87) for cancer mortality; and 0.45 (0.36-0.55) for T2D. Except for cancer mortality and T2D incidence, results became null when adjusted for DLW-calibrated energy intake and BMI.

CONCLUSIONS

Biomarker calibration of FFQ-derived HEI-2010 was associated with lower CVD and cancer incidence and mortality and lower T2D incidence in postmenopausal women. Attenuation after adjustment with BMI and DLW-calibrated energy suggests that energy intake and/or obesity are strong drivers of diet-related chronic disease risk in postmenopausal women. The Women's Health Initiative is registered at clinicaltrials.gov at NCT00000611.

Evaluation of potential metabolomic-based biomarkers of protein, carbohydrate and fat intakes using a controlled feeding study

PURPOSE

Objective biomarkers of dietary exposure are needed to establish reliable diet-disease associations. Unfortunately, robust biomarkers of macronutrient intakes are scarce. We aimed to assess the utility of serum, 24-h urine and spot urine high-dimensional metabolites for the development of biomarkers of daily intake of total energy, protein, carbohydrate and fat, and the percent of energy from these macronutrients (%E).

METHODS

A 2-week controlled feeding study mimicking the participants' habitual diets was conducted among 153 postmenopausal women from the Women's Health Initiative (WHI). Fasting serum metabolomic profiles were analyzed using a targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for aqueous metabolites and a direct-injection-based quantitative lipidomics platform. Urinary metabolites were analyzed using ¹H nuclear magnetic resonance (NMR) spectroscopy at 800 MHz and by untargeted gas chromatography-mass spectrometry (GC-MS). Variable selection was performed to build prediction models for each dietary variable.

RESULTS

The highest cross-validated multiple correlation coefficients (CV-R²) for protein intake (%E) and carbohydrate intake (%E) using metabolites only were 36.3 and 37.1%, respectively. With the addition of established dietary biomarkers (doubly labeled water for energy and urinary nitrogen for protein), the CV-R² reached 55.5% for energy (kcal/d), 52.0 and 45.0% for protein (g/d, %E), 55.9 and 37.0% for carbohydrate (g/d, %E).

CONCLUSION

Selected panels of serum and urine metabolites, without the inclusion of doubly labeled water and urinary nitrogen biomarkers, give a reliable and robust prediction of daily intake of energy from protein and carbohydrate.

The Pah-R261Q mouse reveals oxidative stress associated with amyloid-like hepatic aggregation of mutant phenylalanine hydroxylase

Phenylketonuria (PKU) is caused by autosomal recessive variants in phenylalanine hydroxylase (PAH), leading to systemic accumulation of L-phenylalanine (L-Phe) that may reach neurotoxic levels. A homozygous Pah-R261Q mouse, with a highly prevalent misfolding variant in humans, reveals the expected hepatic PAH activity decrease, systemic L-Phe increase, L-tyrosine and L-tryptophan decrease, and tetrahydrobiopterin-responsive hyperphenylalaninemia. Pah-R261Q mice also present unexpected traits, including altered lipid metabolism, reduction of liver tetrahydrobiopterin content, and a metabolic profile indicative of oxidative stress. Pah-R261Q hepatic tissue exhibits large ubiquitin-positive, amyloid-like oligomeric aggregates of mutant PAH that colocalize with selective autophagy markers. Together, these findings reveal that PKU, customarily considered a loss-of-function disorder, can also have toxic gain-of-function contribution from protein misfolding and aggregation. The proteostasis defect and concomitant oxidative stress may explain the prevalence of comorbid conditions in adult PKU patients, placing this mouse model in an advantageous position for the discovery of mutation-specific biomarkers and therapies.

Resting energy expenditure in cancer patients: Agreement between predictive equations and indirect calorimetry

BACKGROUND/OBJECTIVES

Disorders of energy metabolism is a common phenomenon in cancer patients. Changes in resting energy expenditure (REE) combined with inadequate nutrition support appear to be causes of nutritional depletion in cancer patients. In clinical practice, REE is typically calculated using predictive equations. The aim of this study was to determine the agreement between REE estimated by predictive equations and REE measured by IC in Portuguese cancer patients. Differences in measured REE between patients with different types of digestive cancers were also assessed.

SUBJECTS/METHODS

REE was measured by indirect calorimetry (IC) in 61 patients with cancer diagnosis (gastric cancer, cholangiocarcinoma, pancreatic cancer, liver cancer and colorectal cancer). Measured REE values were compared with those estimated by equations of Harris-Benedict, Schofield, Ireton-Jones, Mifflin-St.Jeor and Barcellos I and II.

RESULTS

Mean Respiratory Quotient (RQ) was 0.77 ± 0.09, which indicates high lipids utilization as substrate. No statistically significant differences between REE or RQ from patients with different cancer types were observed. All equations underestimate REE: Harris-Benedict, mean difference -648 kcal (limits of agreement +627 to -1923 kcal); MifflinSt.Jeor, mean difference -694 kcal (limits of agreement +544 to -193 kcal); Schofield, mean difference -531 kcal (limits of agreement +662 to -1723 kcal); and Ireton-Jones, mean difference -556 kcal (limits of agreement +774 to -1887 kcal). Barcellos I and II showed lower mean difference when compared to measured REE, +59 and + 52 kcal, respectively, although presenting wide limits of agreement, +1542 to -1424 kcal and +1429 to -1326, respectively.

CONCLUSIONS

Although Barcellos Equations underestimate less and enable more accurate average REE prediction in cancer patients, still present wide limits of agreement and therefore clinically important differences in REE estimation may be found at individual level. Our results support the appropriateness of measuring REE by IC to better adequate the nutrition support to cancer patients. Further research is needed to improve the current knowledge base of energy expenditure in cancer patients, and to improve the accuracy of existing predictive equations.

Lifespan of long-lived growth hormone receptor knockout mice was not normalized by housing at 30°C since weaning

Growth hormone receptor knockout (GHRKO) mice are remarkably long-lived and have improved glucose homeostasis along with altered energy metabolism which manifests through decreased respiratory quotient (RQ) and increased oxygen consumption (VO2 ). Short-term exposure of these animals to increased environmental temperature (eT) at 30°C can normalize their VO2 and RQ. We hypothesized that increased heat loss in the diminutive GHRKO mice housed at 23°C and the consequent metabolic adjustments to meet the increased energy demand for thermogenesis may promote extension of longevity, and preventing these adjustments by chronic exposure to increased eT will reduce or eliminate their longevity advantage. To test these hypotheses, GHRKO mice were housed at increased eT (30°C) since weaning. Here, we report that contrasting with the effects of short-term exposure of adult GHRKO mice to 30°C, transferring juvenile GHRKO mice to chronic housing at 30°C did not normalize the examined parameters of energy metabolism and glucose homeostasis. Moreover, despite decreased expression levels of thermogenic genes in brown adipose tissue (BAT) and elevated core body temperature, the lifespan of male GHRKO mice was not reduced, while the lifespan of female GHRKO mice was increased, along with improved glucose homeostasis. The results indicate that GHRKO mice have intrinsic features that help maintain their delayed, healthy aging, and extended longevity at both 23°C and 30°C.

A Comparative Analysis of Equations to Estimate Patient Energy Requirements Following Cardiopulmonary Bypass for Correction of Congenital Heart Disease

BACKGROUND

No consensus exists on the optimal method to estimate resting energy expenditure (REE) in critically ill children following cardiopulmonary bypass (CPB). This study assesses the accuracy of REE estimation equations in children with congenital heart disease following CPB and tests the feasibility of using allometric scaling as an alternative energy prediction equation.

METHODS

A retrospective analysis of a pediatric cohort following CPB (n = 107; median age 5.2 months, median weight 5.65 kg) who underwent serial measures (median 5 measurements) of REE using indirect calorimetry for 72 hours following CPB. We estimated REE using common estimation methods (Dietary Reference Intake, Harris Benedict, Schofield, World Health Organization [WHO]) as well as novel allometric equations. We compared estimated with measured REE to determine accuracy of each equation using overall discrepancy, calculated as a time-weighted average of the absolute deviation.

RESULTS

All equations incorrectly estimated REE at all time points following CPB, with overestimation error predominating. WHO had the lowest discrepancy at 10.7 ± 8.4 kcal/kg/d. The allometric equation was inferior, with an overall discrepancy of 16.9 ± 10.4. There is a strong nonlinear relationship between body surface area and measured REE in this cohort, which is a key source of estimation error using linear equations.

CONCLUSION

In a cohort of pediatric patients with congenital heart disease following CPB, no currently utilized clinical estimation equation reliably estimated REE. Allometric scaling proved inferior in estimating REE in children following CPB. Indirect calorimetry remains the ideal method of determining REE after CPB until nonlinear methods can be derived due to overestimation using linear equations.

Knockout model reveals the role of Nischarin in mammary gland development, breast tumorigenesis and response to metformin treatment

Previously, our lab discovered the protein Nischarin and uncovered its role in regulating cell migration and invasion via its interactions with several proteins. We subsequently described a role for Nischarin in breast cancer, in which it is frequently underexpressed. To characterize Nischarin's role in breast tumorigenesis and mammary gland development more completely, we deleted a critical region of the Nisch gene (exons 7-10) from the mouse genome and observed the effects. Mammary glands in mutant animals showed delayed terminal end bud formation but did not develop breast tumors spontaneously. Therefore, we interbred the animals with transgenic mice expressing the mouse mammary tumor virus-polyoma middle T-antigen (MMTV-PyMT) oncogene. The MMTV-PyMT mammary glands lacking Nischarin showed increased hyperplasia compared to wild-type animal tissues. Furthermore, we observed significantly increased tumor growth and metastasis in Nischarin mutant animals. Surprisingly, Nischarin deletion decreased activity of AMPK and subsequently its downstream effectors. Given this finding, we treated these animals with metformin, which enhances AMPK activity. Here, we show for the first time, metformin activates AMPK signaling and inhibits tumor growth of Nischarin lacking PyMT tumors suggesting a potential use for metformin as a cancer therapeutic, particularly in the case of Nischarin-deficient breast cancers.

Cancer incidence and mortality during the intervention and postintervention periods of the Women's Health Initiative dietary modification trial

BACKGROUND

The Women's Health Initiative (WHI) low-fat (20% kcal) dietary modification (DM) trial (1993-2005) demonstrated a nonsignificant reduction in breast cancer, a nominally significant reduction in ovarian cancer, and no effect on other cancers (mean 8.3 years intervention). Consent to nonintervention follow-up was 83% (n = 37,858). This analysis was designed to assess postintervention cancer risk in women randomized to the low-fat diet (40%) versus usual diet comparison (60%).

METHODS

Randomized, controlled low-fat diet intervention for prevention of breast and colorectal cancers conducted in 48,835 postmenopausal U.S. women, ages 50 to 79 years at 40 U.S. sites. Outcomes included total invasive cancer, breast cancer, and colorectal cancer, and cancer-specific and overall mortality.

RESULTS

There were no intervention effects on invasive breast or colorectal cancer, other cancers, or cancer-specific or overall mortality during the postintervention period or the combined intervention and follow-up periods. For invasive breast cancer, the hazard ratios (HR) and 95% confidence interval (CI) were 0.92 (0.84-1.01) during intervention, 1.08 (0.94-1.24) during the postintervention period, and 0.97 (0.89-1.05) during cumulative follow-up. A reduced risk for estrogen receptor positive/progesterone receptor-negative tumors was demonstrated during follow-up. In women with higher baseline fat intake (quartile), point estimates of breast cancer risk were HR, 0.76 (95% CI, 0.62-0.92) during intervention versus HR, 1.11 (95% CI, 0.84-1.4) during postintervention follow-up (Pdiff = 0.03).

CONCLUSIONS

Dietary fat intake increased postintervention in intervention women; no long-term reduction in cancer risk or mortality was shown in the WHI DM trial.

IMPACT

Dietary advisement to reduce fat for cancer prevention after menopause generally was not supported by the WHI DM trial.

Simultaneous association of total energy consumption and activity-related energy expenditure with risks of cardiovascular disease, cancer, and diabetes among postmenopausal women

Total energy consumption and activity-related energy expenditure (AREE) estimates that have been calibrated using biomarkers to correct for measurement error were simultaneously associated with the risks of cardiovascular disease, cancer, and diabetes among postmenopausal women who were enrolled in the Women's Health Initiative at 40 US clinical centers and followed from 1994 to the present. Calibrated energy consumption was found to be positively related, and AREE inversely related, to the risks of various cardiovascular diseases, cancers, and diabetes. These associations were not evident in most corresponding analyses that did not correct for measurement error. However, an important analytical caveat relates to the role of body mass index (BMI) (weight (kg)/height (m)(2)). In the calibrated variable analyses, BMI was regarded, along with self-reported data, as a source of information on energy consumption and physical activity, and BMI was otherwise excluded from the disease risk models. This approach cannot be fully justified with available data, and the analyses herein imply a need for improved dietary and physical activity assessment methods and for longitudinal self-reported and biomarker data to test and relax modeling assumptions. Estimated hazard ratios for 20% increases in total energy consumption and AREE, respectively, were as follows: 1.49 (95% confidence interval: 1.18, 1.88) and 0.80 (95% confidence interval: 0.69, 0.92) for total cardiovascular disease; 1.43 (95% confidence interval: 1.17, 1.73) and 0.84 (95% confidence interval: 0.73, 0.96) for total invasive cancer; and 4.17 (95% confidence interval: 2.68, 6.49) and 0.60 (95% confidence interval: 0.44, 0.83) for diabetes.