Changes In Body Mass Research Articles

Changes in body composition in early breast cancer patients treated with aromatase inhibitors

PurposeThe aim of the study was to analyze the modification of total and regional body composition in early breast cancer patients treated with aromatase inhibitors (AIs).MethodsThis is a prospective, single-center, observational, longitudinal study. Four-hundred and twenty-eight patients treated with adjuvant aromatase inhibitors were enrolled at the Medical Oncology and Breast Unit of Spedali Civili Hospital in Brescia from September 2014 to June 2022. Several body composition parameters including total and regional fat and lean body mass were investigated with dual-energy X-ray absorptiometry (DXA) scan at baseline and after 18 months of treatment with aromatase inhibitors.ResultsA significant increase in fat body mass (mean + 7.2%, 95% confidence interval [CI]: 5.5;8.9%) and a reduction in lean body mass (mean −3.1%, 95% CI −3.9; −2.4) were documented in this population. The changes in fat and lean body mass varied considerably according to different body districts ranging between + 3.2% to + 10.9% and from−1.3% to −3.9%, respectively.ConclusionAromatase inhibitor adjuvant therapy in early breast cancer is associated with changes in body composition, with a wide variability among different body districts, leading to a risk of sarcopenic obesity. Supervised physical exercise that focuses on single body parts that may display detrimental variations may be beneficial for AIs treated patients.

The Effect of Palmitoylethanolamide (PEA) on Skeletal Muscle Hypertrophy, Strength, and Power in Response to Resistance Training in Healthy Active Adults: A Double-Blind Randomized Control Trial

BackgroundPalmitoylethanolamide (PEA) has analgesic/anti-inflammatory properties that may be a suitable alternative to over-the-counter (OTC) non-steroidal analgesics/anti-inflammatories. While OTC pain medications can impair strength training adaptations, the mechanism of action of PEA is distinct from these and it may not negatively affect skeletal muscle adaptations to strength training.MethodsThe primary aim of this study was to investigate the effects of daily PEA supplementation (350 mg Levagen + equivalent to 300 mg PEA) combined with 8-weeks of resistance training on lean body mass with secondary aims addressing strength, power, sleep, and wellbeing compared to placebo (PLA) in young, healthy, active adults. In a randomized, controlled, double-blinded trial, 52 untrained, recreationally active participants aged 18–35 y were allocated to either the PEA or PLA groups. Participants consumed either 2 × 175 mg Levagen + PEA or identically matched maltodextrin capsules during an 8-week period of whole-body resistance training. This trial assessed the pre- to post- changes in total and regional lean body mass, muscular strength (1-RM bench, isometric mid-thigh pull), muscular power [countermovement jump (CMJ), bench throw], pain associated with exercise training, sleep, and wellbeing compared with the PEA or PLA condition.Results48 Participants were included in the final intention to treat (ITT) analysis and we also conducted per protocol (PP) analysis (n = 42). There were no significant between-group differences for total or regional lean muscle mass post-intervention. There was a significantly higher jump height (CMJ) at week 10 in the PEA group compared to the PLA (Adjusted mean difference [95% CI] p-value; ITT: − 2.94 cm [− 5.15, − 0.74] p = 0.010; PP: − 2.93 cm [− 5.31, − 0.55] p = 0.017). The PLA group had higher 1-RM bench press post-intervention compared with the PEA group (ITT: 2.24 kg [0.12, 4.37] p = 0.039; PP: 2.73 kg [0.40, 5.06] p = 0.023). No significant treatment effects were noted for any of the other outcomes.ConclusionPEA supplementation, when combined with 8 weeks of strength training, did not impair lean mass gains and it resulted in significantly higher dynamic lower-body power when compared with the PLA condition.Trial Registration: Australian New Zealand Clinical Trials Registry (ANZCTR: ACTRN12621001726842p).

Water Availability and Temperature as Modifiers of Evaporative Water Loss in Tropical Frogs.

Water plays a notable role in the ecology of most terrestrial organisms due to the risks associated with water loss. Specifically, water loss in terrestrial animals happens through evaporation across respiratory tissues or the epidermis. Amphibians are ideal systems for studying how abiotic factors impact water loss since their bodies often respond quickly to environmental changes. While the effect of temperature on water loss is well known across many taxa, we are still learning how temperature in combination with humidity or water availability affects water loss. Here, we tested how standing water sources (availability) and temperature (26 and 36°C) together affect water loss in anuran amphibians using a Bayesian framework. We also present a conceptual model for considering how water availability and temperature may interact, resulting in body mass changes. After accounting for phylogenetic and time autocorrelation, we determined how different variables (water loss and uptake rates, temperature, and body size) affect body mass in three species of tropical frogs (Rhinella marina, Phyllobates terribilis, and Xenopus tropicalis). We found that all variables impacted body mass changes, with greater similarities between P. terribilis and X. tropicalis, but temperature only showed a notable effect in P. terribilis. Furthermore, we describe how the behavior of P. terribilis might affect its water budget. This study shows how organisms might manage water budgets across different environments and is important for developing models of evaporative water loss and species distributions.

Role of gastrointestinal appetite hormones in the success of body mass loss during interventions based on exercise combined with restricted energy intake diets with different fat and carbohydrate content

Restriction of energy intake is an effective strategy for achieving body mass loss(1). However, it leads to gastrointestinal appetite hormonal changes, which are expected to enhance hunger, reduce satiety, and possibly impair the ability to comply with prescribed intervention(2). Exercise interventions, on the other hand, did not modify gastrointestinal appetite hormones(3) and there is some evidence that postprandial appetite hormone responses after a low carbohydrate-high fat meal (LCHF) are more favorable than after high carbohydrate-low fat meal (HCLF) meal (4). This study investigated how energy-restricted diets based on LCHF and HCLF meals and combined with exercise affect body weight, and gastrointestinal appetite hormones and explored the relationship between body mass changes and changes in gastrointestinal appetite hormones.Twenty-seven overweight and obese females (age: 35 ± 9.35 years, BMI: 31.64 ± 5.08 kg/m2) completed a randomized parallel design study and underwent a 4-week intervention consisting of brisk walking combined with either consumption of calorie-restricted HCLF or LCHF diet. Participants underwent a 5-hour experimental trial before and after the interventions, which included body weight measurements and fasting and postprandial blood sample collection for gastrointestinal appetite hormone measurements.Both interventions significantly reduced body mass (HCLF group, −2.1 ± 1.7 Kg: LCHF group, -1.7 ± 1.7 Kg, P < 0.05 for both groups), but changes between the groups were not significant (P>0.05). Body mass changes were individual and ranged from -0.4 kg to −5.3 kg and from +1 kg to −4.4 kg in the HCLF and LCHF groups, respectively. The interventions had no impact on mean values of time- averaged postprandial concentrations of ghrelin, PYY, and GLP-1 but there was large individual variability in changes of these hormones. Results combined from both groups revealed that changes in ghrelin ranged from +549.3 to -407.7 pg/ml, in PYY from −132.5 to + 96.4 pg/ml and in GLP-1 from −6.6 to +19.5 pg/ml. Correlation, investigated on the data from both groups combined, between changes in body mass and changes in ghrelin (r = −0.18, P= 0.41), PYY (r = −0.04, P =0.87), and GLP-1 (r = 0.11, P = 0.64) were not significant.In conclusion, the extent of body mass loss during interventions based on restricted energy intake diets combined with exercise is not related to the carbohydrate and fat content of the diet. Our findings also suggest that the success of body mass loss cannot be predicted by changes in postprandial concentrations of gastrointestinal appetite hormones.

Assessment of Hydration Status Using Conventional Method and Salivary Osmolarity as a Point-of-care Tool.

Dehydration is a well-known problem worldwide, and its assessment can be challenging due to confusing physical signs. The most effective way to assess hydration status is through the costly stable isotope methodology, but this approach has practical limitations. More commonly accepted and utilized indicators of hydration status are hematological and urinary parameters. However, hematological markers require invasive methods, and urinary markers have varying degrees of success in tracking hydration changes. While alterations in body weight can serve as a means of promptly evaluating hydration status, various factors such as food consumption, fluid intake, fecal losses, and urine production can impact these changes. Researchers have turned their attention to saliva as a potential marker and point-of-care (POC) testing to address the limitations of existing biomarkers. Saliva is appealing due to its easy collection process and similarities to extracellular fluid in terms of water and ion concentrations. Recent studies have shown that saliva flow rate, osmolarity/osmolality, and total protein concentration can effectively monitor changes in body mass during acute dehydration. Misdiagnosing dehydration can have severe clinical consequences, leading to morbidity and even mortality. This narrative review focuses on recognizing the significance of hydration assessment, monitoring, and the potential of salivary osmolarity (SOSM) as an assessment tool. Healthcare professionals can improve their practices and interventions to optimize hydration and promote overall wellness using such tools.

Comparison of resistance training using barbell half squats and trap bar deadlifts on maximal strength, power performance, and lean mass in recreationally active females: an eight-week randomised trial

BackgroundThe aim of this study was to investigate the effect of high load resistance training using barbell half squats compared with trap bar deadlifts on maximal strength, power performance, and lean mass in recreationally active females.MethodsTwenty-two recreationally active female participants (age: 26.9 ± 7.7 yrs.; height: 166.0 ± 5.1 cm; weight: 68.6 ± 9.9 kg) were randomly assigned to either a barbell half squat group (SG: n = 10) or trap bar deadlift group (DG: n = 12). Training consisted of twice-weekly sessions for eight weeks. Both groups completed one-repetition maximum (1RM) testing for both barbell half squat and trap bar deadlift groups. Countermovement jump (CMJ) and sprint performance were also assessed. Total body (TBLM) and leg lean mass (LLM) were measured with dual-energy x-ray absorptiometry. Between-group differences were analysed using analysis of covariance.ResultsSG tended to improve 1RM half squat (21.0 ± 11.5 kg vs. 13.1 ± 7.5 kg) more than DG (mean difference (MD): 8.0 kg, 95% CI: -0.36 – 16.3 kg). A similar pattern in favour of DG (18.4 ± 11.2 vs. 11.7 ± 8.1 kg) compared to SG was observed (MD: 6.5 kg, 95% CI: -2.5 – 15.6 kg). No between-group differences for sprint, jump or lean body mass changes was observed. For groups combined, the following changes in CMJ (2.0 ± 2.4 cm), 5-m sprint (-0.020 ± 0.039 s), 15-m sprint (-0.055 ± 0.230 s), TBLM (0.84 ± 1.12 kg), and LLM (0.27 ± 0.59 kg) was observed.ConclusionsAn exercise intervention consisting of half squats or trap bar deadlift were associated with improved muscle strength, power, and lean mass. Our findings suggests that in recreationally active females, exercise selection is less of a concern provided that heavy loads are applied, and relevant muscle groups are targeted.

Habitat type modulates sharp body mass oscillations in cyclic common vole populations

Cyclic rodent populations exhibit pronounced changes in body mass associated with the population cycle phase, long-known as Chitty effect. Although Chitty effect is a common epiphenomenon in both America and Europe, there is still incomplete evidence about the generality of these patterns across the entire range of most species. Moreover, despite decades of research, the underlying factors driving Chitty effect remains poorly understood. Here, we examined the influence of intrinsic and extrinsic factors that may underlie observed patterns in vole size variation in the Iberian common vole Microtus arvalis asturianus. We weighed and measured 2816 adult voles that were captured during 6 trapping periods. Vole numbers and body mass showed strong period- and phase-related variation both in females and males, demonstrating marked Chitty effect in the studied population. Body mass of adult males correlated with body length, evidencing that heavier males are also structurally larger. Statistical models showed that probability of occurrence of large-sized vole (> 37 g) was significantly more likely in reproductive males, during increase and peak phases, and it was modulated by habitat, with crop fields and field margins between crops showing an increased likelihood. We suggest an effect of the habitat on vole body mass mediated by predation.

Effects of short-term pre-competition weight loss on certain physiological parameters and strength change in elite boxers.

Athletes in certain sports aim to gain an advantage by competing in a lower body mass class instead of competing in their own body mass class. This study aims to reveal certain physiologic and strength changes in elite male boxers who lost body mass rapidly before the competition. 30 thirty boxers who were aged between 19-24 years and having a mean age of 7.4 years participated in the study. To evaluate the effect of short-term dietary intake interventions on body composition and muscle strength before the competition, boxers were divided into three groups: control (C), exercise+diet1 (E+D1) and exercise+diet2 (E+D2) groups. The dietary habits of the participants were controlled and they participated in the training program. The data of the study consisted of variables such as body mass, height, regional muscle mass, body fat percentage, biceps and femur bicondylar circumference measurements before the competitions. Isometric strength measurements of knee extensors and flexors and shoulder internal and external rotators were also recorded. Physiologic parameters such as body mass change, BMI level, body fat percentage and leg muscle ratios of E+D2 were significantly decreased compared to C and E+D1 groups. Furthermore, submaximal and maximal strength production in knee extensors and flexors as well as shoulder internal and external rotators were significantly decreased in E+D2 compared to C and E+D1 groups. The tendency to lose body mass quickly in a short of time may give the desired results in terms of BMI, body mass and fat percentage, but it may cause strength losses in boxers during the competition period.

#208 Obesity is associated with incident chronic kidney disease in individuals with normal renal function

Abstract Background and Aims Obesity is a representative modifiable risk factor for chronic kidney disease (CKD). This study aimed to investigate whether both body mass index (BMI), waist-to-hip ratio (WHR) and changes of WHR during follow-up are risk factors for development of incident CKD. Method A total of 2 711 participants from a community-based cohort with normal renal function were prospectively analyzed. Among participants with obesity, we analyzed the change in WHR to evaluate the association of obesity reduction with CKD development. Results During a mean follow-up of 11.03 ± 4.22 years, incident CKD occurred in 190 (7.0%) participants. In the fully adjusted multivariable Cox proportional hazard models, the risk of incident CKD increased with higher BMI (hazard ratio, 1.06; 95% confidence interval, 1.00–1.11; p = 0.033) and higher WHR (hazard ratio, 1.33; 95% confidence interval, 1.07–1.66; p = 0.009). In the Kaplan–Meier analysis, cumulative adverse renal events were significantly more common in the maintained obesity group than in the reduced obesity group (p = 0.001). Conclusion Both higher BMI and WHR were associated with development of CKD, but the magnitude of the effect of WHR was higher than that of BMI. Moreover, reducing obesity would be beneficial for renal prognosis.

The impact of weather conditions on the competition and breeding success of three sympatric hornbill species in a semi-arid region

Recent studies have highlighted the vulnerability of hornbills breeding in hot, arid environments, raising concern about the species’ persistence with climate change. Hornbills are, however, a widespread avian family found in various climates in Africa and Asia. In this study, we investigated the factors impacting the breeding phenology of three sympatric African hornbill species in a semi-arid environment. We found that rainfall was associated with breeding initiation and breeding success in all three species (African grey hornbill Lophoceros nasutus, Southern yellow-billed hornbill Tockus leucomelas, and Southern red-billed hornbill Tockus rufirostris). Breeding success and chick body mass change of African grey hornbills and Southern yellow-billed hornbills, but not Southern red-billed hornbills, were negatively impacted by high air temperatures during the breeding season. This study shows that Southern red-billed hornbills were more successful at producing offspring compared to African grey hornbills and Southern yellow-billed hornbills, which was likely due to their later breeding initiation compared to the other two species. Future changes in rainfall patterns may cause the African grey hornbills and Southern yellow-billed hornbills to delay breeding activities. Delayed breeding could result in a greater overlap of the nesting period of the three species, which would, in turn, increase the competition for food and suitable nesting sites. This study confirms that also in semi-arid areas, climate change has the potential to affect the breeding success of hornbills.

Body fat and circulating leptin levels in the captive short-beaked echidna (Tachyglossus aculeatus)

It is possible that the reproductive strategy of the short-beaked echidna is related to seasonal changes in fat deposition and energy availability, regulated by seasonal changes in endocrine function. We predicted that circulating leptin levels would be directly proportional to adiposity during most of the year, but that a change in this relationship would occur during the pre-breeding season to allow increased fat deposition. To test this hypothesis, we made use of a captive colony of echidnas to describe and quantify changes in fat distribution and the adipostatic hormone leptin. First we assessed seasonal changes in circulating leptin levels, body mass and adiposity for three male and three female adult echidnas maintained on a standard diet. Second, we explored the relationship between circulating leptin levels and increased caloric intake for an additional five adult female echidnas that were provided with supplemented nutrition. Third we visualised fat distribution in male and female adult echidnas using magnetic resonance imaging (MRI) before and after the breeding season, to determine where fat is deposited in this species. For echidnas maintained on the standard diet, there were no seasonal changes in body mass, body fat or plasma leptin levels. However, female echidnas provided with supplemented nutrition had significantly elevated plasma leptin levels during the breeding season, compared to the pre-and post- breeding periods. MRI showed substantial subcutaneous fat depots extending dorso-laterally from the base of the skull to the base of the tail, in both sexes. Pre-breeding season, both sexes had considerable fat deposition in the pelvic/rump region, whilst the female echidna accumulated most fat in the abdominal region. This study shows that male and female echidnas accumulate body fat in the pelvic/rump and the abdominal regions, respectively and that circulating leptin may promote fattening in female echidnas during the breeding season by means of leptin resistance. However, further research is required to evaluate the precise relationship between seasonal changes in leptin and adiposity.

Effects of tag mass on the physiology and behaviour of common noctule bats

BackgroundExternal tags, such as transmitters and loggers, are often used to study bat movements. However, physiological and behavioural effects on bats carrying tags have rarely been investigated, and recommendations on the maximum acceptable tag mass are rather based on rules of thumb than on rigorous scientific assessment.MethodsWe conducted a comprehensive three-step assessment of the potential physiological and behavioural effects of tagging bats, using common noctules Nyctalus noctula as a model. First, we examined seasonal changes in body mass. Second, we predicted and then measured potential changes in flight metabolic rate in a wind tunnel. Third, we conducted a meta-analysis of published data to assess effects of different tag masses on the weight and behaviour of bats.ResultsIndividual body mass of common noctules varied seasonally by 7.0 ± 2.6 g (range: 0.5–11.5 g). Aerodynamic theory predicted a 26% increase in flight metabolic rate for a common noctule equipped with a 3.8 g tag, equating to 14% of body mass. In a wind tunnel experiment, we could not confirm the predicted increase for tagged bats. Our meta-analysis revealed a weak correlation between tag mass and emergence time and flight duration in wild bats. Interestingly, relative tag mass (3–19% of bat body mass) was not related to body mass loss, but bats lost more body mass the longer tags were attached. Notably, relatively heavy bats lost more mass than conspecifics with a more average body mass index.ConclusionBecause heavy tags (> 3 g) were generally used for shorter periods of time than lighter tags (~ 1 g), the long-term effects of heavy tags on bats cannot be assessed at this time. Furthermore, the effects of disturbance and resource distribution in the landscape cannot be separated from those of tagging. We recommend that tags weighing 5–10% of a bat’s mass should only be applied for a few days. For longer studies, tags weighing less than 5% of a bat's body mass should be used. To avoid adverse effects on bats, researchers should target individuals with average, rather than peak, body mass indices.

Evaluation of methods used to improve grasslands as ring‐necked pheasant brood habitat

AbstractRing‐necked pheasant (Phasianus colchicus) demographic response is sensitive to chick survival and nest success. The establishment and management of grasslands within agricultural landscapes, often through cropland conversion programs (e.g., Conservation Reserve Program [CRP]), have positive impacts on survival and nest success. Newly established CRP and early successional habitat can provide vegetative structure selected by pheasant chicks. Ideal brood habitat provides an abundance of arthropods, an open understory promoting efficient chick movement, and a protective canopy cover. However, the natural succession of grasslands changes desired vegetative structure and challenges managers with providing adequate habitat for pheasant chicks. We investigated the efficacy of different methods of CRP management, including haying, burning, herbicide application, interseeding, and grazing, to provide adequate brood rearing habitat in cool‐ and warm‐season grasslands. We assessed chick body mass change using human‐imprinted ring‐necked pheasant chicks and investigated changes in vegetation composition and structure in relation to various habitat treatments in north‐central and north‐eastern South Dakota during mid‐June and mid‐July of 2013, 2014, and 2015. Generally, treatments that incorporated interseeding, herbicide application, or their combination had the greatest chick mass gain, reduced litter cover and depth, and increased bare ground and forb cover. Effective management for brood habitat may require more aggressive techniques than simple haying or prescribed fire techniques.

Whole body sweat rate prediction: outdoor running and cycling exercise.

Our aim was to develop and validate separate whole body sweat rate prediction equations for moderate to high-intensity outdoor cycling and running, using simple measured or estimated activity and environmental inputs. Across two collection sites in Australia, 182 outdoor running trials and 158 outdoor cycling trials were completed at a wet-bulb globe temperature ranging from ∼15°C to ∼29°C, with ∼60-min whole body sweat rates measured in each trial. Data were randomly separated into model development (running: 120; cycling: 100 trials) and validation groups (running: 62; cycling: 58 trials), enabling proprietary prediction models to be developed and then validated. Running and cycling models were also developed and tested when locally measured environmental conditions were substituted with participants' subjective ratings for black globe temperature, wind speed, and humidity. The mean absolute error for predicted sweating rate was 0.03 and 0.02 L·h-1 for running and cycling models, respectively. The 95% confidence intervals for running (+0.44 and -0.38 L·h-1) and cycling (+0.45 and -0.42 L·h-1) were within acceptable limits for an equivalent change in total body mass over 3 h of ±2%. The individual variance in observed sweating described by the predictive models was 77% and 60% for running and cycling, respectively. Substituting measured environmental variables with subjective assessments of climatic characteristics reduced the variation in observed sweating described by the running model by up to ∼25%, but only by ∼2% for the cycling model. These prediction models are publicly accessible (https://sweatratecalculator.com) and can guide individualized hydration management in advance of outdoor running and cycling.NEW & NOTEWORTHY We report the development and validation of new proprietary whole body sweat rate prediction models for outdoor running and outdoor cycling using simple activity and environmental inputs. Separate sweat rate models were also developed and tested for situations where all four environmental parameters are not available, and some must be subsequently estimated by the user via a simple rating scale. All models are freely accessible through an online calculator: https://sweatratecalculator.com. These models, via the online calculator, will enable individualized hydration management for training or recreational cycling or running in an outdoor environment.

Abstract PO1-16-11: Real-world features and outcomes of young advanced breast cancer (ABC) patients (pts) from RegistEM (GEICAM/2014-03) study

Abstract Background: BC is the most incident cancer worldwide in < 40 years old (y) women. Increasing body mass index and changes in reproductive history contribute to the growing incidence of premenopausal BC. A higher proportion of luminal B-like and estrogen receptor negative (ER─) tumors, an increased risk of early relapse, and more unfavorable longer-term outcomes for young women with ER+ tumors when compared to older women, have been reported. In this analysis, we focus on age-specific BC characterization from a real-world population-based perspective. Methods: Pts were enrolled in the non-interventional and ambispective RegistEM study in ABC diagnosed between 2016 and 2019. We describe the features and outcomes of < 50 y pts at their initial BC diagnosis according to their BC subtype. BC subtypes were based on the most recent tumor tissue sample (distant metastasis, and in its absence, primary BC). Comparisons between < 40 and ≥ 50 y groups were performed. Results: Pts < 50 y represent 39% (n=685) of total pts with available data (n=1739, any age group) in the registry. By age, 12% (n=212) were < 40y, and 27% (n=473) 40-49y. At first BC diagnosis, 75% and 25% pts had early BC (EBC) and de novo metastatic BC (MBC), respectively. In EBC pts, stage II (50%) and III (28%) were the most frequent at diagnosis; invasive non-special type carcinoma was the predominant morphology, and grade 2 was the most common histological grade, but grade 3 was predominant in TN pts and HER2+ < 40y pts. The median time to recurrence was < 2y in TN pts, 3y in HER2+ pts, and 6y in luminal HER2─ pts. At ABC diagnosis, the median age was 47y, all pts were female but one, 98% white, and 60% premenopausal (94% were premenopausal at EBC diagnosis). A family history of BC and/or ovarian cancer was reported in 34% pts, and a hereditary-risk genetic test was performed in 39% (254 of 652) pts; 12% (n=30) had BRCA1/2 mutations, with a proportion higher in TN pts (9 of 33, 27%) vs. luminal HER2─ (21 of 183, 12%) and HER2+ (0 of 38) pts. Visceral disease was the most frequent in all subgroups, highlighting statistical differences (p=0.022) between age groups ( < 40y 55% vs. ≥50y 71%) only in TN pts. 60% had ≤ 2 locations involved, similarly in all subgroups. The presence of >2 metastatic locations was statistically higher in HER2+ pts ≥50y (54%) vs both < 40y (32%) and 40-49y (48%). Brain disease was more present at ABC diagnosis in TN (9%) and HER2+ (7%) than in luminal HER2─ (3%). Median no. of treatment lines (L) was 3 (range 0-11), and median follow-up 44 mo (95% CI: 41-44). 99% pts received 1L, the distribution of treatments by BC subtype within each age subgroup was similar; median duration of 1L was 21 months (mo) in luminal HER2─, 17 mo in HER2+, and 5 mo in TN pts. 68% of pts who received 1L, reached 2L. Duration of 2L dropped dramatically: 8 mo in luminal HER2─, 6 mo in HER2+, and 2 mo in TN pts. No differences between ≥50y and the rest of pts were observed in PFS for any treatment line. 49% pts had died at the database cut-off date (05-April-23), with no differences between age groups, but TN pts had the highest death rate (80%). Additional data according to BC subtypes and age groups are in the table. Conclusions: Luminal HER2─ was the predominant BC subtype in all age subgroups. Visceral disease was more prevalent in young TN pts compared to older pts. TNBC pts experienced a shorter median time to recurrence and the highest mortality rate regardless of age, compared to HER2+ and luminal HER2- pts, indicating the need for targeted interventions in this subgroup. Citation Format: Sara López-Tarruella, Angel Guerrero, Isabel Álvarez, Silvia Antolin Novoa, Ariadna Tibau, Josefina Cruz, César A Rodríguez, Purificación Martínez, J. Ignacio Chacón, María Hernández, Mireia Margelí, Encarna Adrover, Catalina Falo, Iria González, Álvaro Rodríguez-Lescure, María Marín, César Gómez, Juan de la Haba-Rodríguez, J. José Illaramendi, Raquel Andrés, Andrea Blasco, Mª José Escudero, Susana Bezares, Federico Rojo. Real-world features and outcomes of young advanced breast cancer (ABC) patients (pts) from RegistEM (GEICAM/2014-03) study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-16-11.

Ad Libitum Drinking Prevents Body Mass Loss Across Consecutive Workdays in Heat

Hydration practices across consecutive days of heavy-intensity work in heat when fluid is freely available is unknown. Without this information it remains unknown whether hydration modifies heat strain under hot working conditions and whether worker recommendations adequately maintain hydration status. We hypothesized that participants would maintain hydration status including daily percent change in body mass across workdays. Fifteen healthy, unacclimated participants (7 Females, Age: 27±6 y, Body mass: 75.0±14.4 kg, Body fat: 26.6±5.8%) completed three consecutive days (Day 1, Day 2, Day 3) of 4 h of 395±10 W work to a work/rest cycle of 45/15 min in a 36.3±0.8°C, 21±5% relative humidity environment. Participants were offered 237 mL of a sport drink every 20 min to consume ad libitum. Urine flow rate (UFR) was measured before work. Urine specific gravity (USG) and nude body mass were measured before and after work. Thirst and fluid consumption were measured throughout work. USG before work was not different between Day 1 (1.013±0.010) and Day 2 (1.013±0.010, p=0.822), but was greater before work on Day 3 (1.015±0.010, p=0.046) compared to Day 2. Change in USG from before to after work was not different between Day 1 (+0.003±0.008) and Day 2 (+0.000±0.006, p=0.123), but was lower on Day 3 (-0.002±0.006, p=0.021) compared to Day 1, with no difference between Day 2 and Day 3 (p=0.058). Before work body mass was not different across days (p=0.103). Daily percent change in body mass was not different across days (p=0.366, Day 1: 0.53±1.11%, Day 2: 0.18±0.95%, Day 3: 0.18±0.81%), indicating weight gain each day. Sweat rate (p=0.790) and UFR (p=0.469) were not different among days. Participants consumed 77±18% (Day 1), 82±19% (Day 2), and 82±16% (Day 3) of fluid offered (p=0.401), equaling 31±10 mL/kg (Day 1), 33±11 mL/kg (Day 2), 33±10 mL/kg (Day 3) (p=0.370). Maximum thirst was greater on Day 1 (3.5±1.1) compared to Day 3 (2.9±1.0, p=0.045) with no difference between Day 1 and Day 2 (3.4±1.4, p=0.648) or between Day 2 and Day 3 (p=0.121). This study demonstrates consistent hydration practices and no differences in hydration status across three consecutive days of high-intensity work in heat when fluid is freely available. Under these conditions, workers can consume fluids ad libitum and worker recommendations for hydration during heat stress should be revisited. This project was funded my the National Institute for Occupational Safety and Health (1K01OH012016-01A1). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Examining the Impact of Environmental and Genetic Factors that Influence Sarcospan Expression in the Heart

Objective: Susceptibility to cardiac injury can be hereditary and the most common causes include genetic variations in proteins regulating lipid metabolism, arterial hypertension, diabetes, body-mass index as well as environmental causes such as smoking. Sarcospan (SSPN) is an integral member of the dystrophin-glycoprotein complex (DGC) and has an important role in stabilizing the muscle membrane of striated muscle. Genetic variants in the SSPN gene have been linked with increased cardiovascular disease risk and studies are ongoing to identify underlying mechanisms. Our studies using perfused mouse hearts subjected to acute ischemia/reperfusion injury indicate that SSPN deletion increases infarct size and arrhythmia risk (Hwang et al, IJMS, 2023). In addition, adult SSPN−/− cardiomyocytes were found to have decreased antioxidative capacity and heightened susceptibility to oxidative stress. Therefore, we hypothesize that genetic factors that decrease cardiac SSPN expression will increase cardiac susceptibility of mice exposed to conditions of prolonged oxidative stress. In this study we examine the role of SSPN to heart injury caused by chronic oxidative stress mediated by cigarette smoke (CS). Methods: To assess the impact of chronic oxidative stress conditions on SSPN expression in the heart 2 month-old WT C57BL/6J mice were exposed to 4 months CS. We found that SSPN expression was significantly reduced the CS exposed hearts. Since CS increases oxidative damage and deteriorates antioxidant defenses of the heart and vascular system, we examined the combined impact of SSPN deficiency and chronic oxidative stress. To address this, 7-month-old WT and SSPN−/− male and female mice were exposed to CS for 4 months. The mice were assessed after CS for body composition (EchoMRI), glucose tolerance testing and echocardiography. Tissue histology, immunoblotting of oxidative and inflammatory stress markers, serum inflammatory markers were assessed. Lung fibroblasts were isolated from the smoked and non-smoked groups to evaluate inflammatory, fibrotic, and oxidative stress pathway activation to respective stimuli. Results: Preliminary findings indicate that after CS SSPN−/− hearts exhibit larger areas of myocardial damage than WT mice. Surprisingly, after CS the SSPN−/− mice showed better glucose tolerance than WT mice and no significant changes in body mass. Minor decrements were found in the cardiac function of the CSE mice. Exposure of lung fibroblasts obtained from non-smoked SSPN−/− mice to innate immune ligands revealed activation of specific pro-inflammatory pathways.Conclusions: SSPN-deficiency increases susceptibility to cardiac injury in mice subjected to CS exposure, likely through crosstalk mechanisms that exist between oxidative and inflammatory pathways that SSPN appears to influence. Funding Sources: Florida Department of Health, James and Esther King #21K12. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Responses of Healthy Young and Older Adults to Short-Term Passive Heat Acclimation

Context: Aging is accompanied by a reduced capacity to dissipate heat. Heat acclimation has been shown to improve heat loss capacity in young healthy adults, yet few studies have investigated the capacity of older adults to adapt to repeated bouts of heat exposure, particularly when using a passive heat acclimation protocol. Furthermore, it remains unclear whether the magnitude of adaptations is affected by age. Objective and hypothesis: To compare physiological adaptations following 7 consecutive days of passive heat exposure between healthy young and older adults. We hypothesized that heat acclimation would enhance heat loss capacity in both groups but to a higher extent in young than in older adults. Methods: Fourteen healthy young (5F/9M, 27 ± 5 years) and 9 older adults (6F/3M, 66 ± 5 years) were exposed to passive heat stress with a water-perfused suit before (pre) and after (post) 7 consecutive days of immersion in 40°C water (~30 min to reach a rectal temperature of 38.5°C, followed by 60 min ≥38.5°C). During the pre/post heat stress test, mean body temperature was computed as 0.8 × esophageal temperature + 0.2 × mean skin temperature. Local sweat rate (LSR) and cutaneous vascular conductance (CVC) were measured at the forearm level. The mean body temperature onset thresholds of LSR and CVC were determined by segmented linear regression. During acclimation visits, rectal temperature and change in body mass were measured. Data are presented as means ± standard deviation or mean differences [95% confidence interval]. Results: Immersion duration (young: 90 ± 10, older: 92 ± 9 min, p=0.53), water temperature (young: 40.3 ± 0.3, older: 40.0 ± 0.5°C, p=0.09) and mean rectal temperature (young: 38.9 ± 0.1, older: 38.8 ± 0.1°C, p=0.07) during heat acclimation did not differ significantly between groups. In response to heat acclimation, rectal temperature decreased similarly ( p=0.36) in young (-0.33°C [-0.50, -0.16]) and older adults (-0.46°C [-0.68, -0.25]) from day 1 to day 7 whereas sweat rate increased to a higher extent ( p=0.05) in young (+511 mL/h [285, 738]) compared with older adults (+232 mL/h [112, 352]). Heat acclimation similarly reduced the mean body temperature onset threshold for CVC in young (-0.18°C [-0.32, -0.05]) and older adults (-0.19°C [-0.36, -0.02]) ( p=0.91), as well as, the mean body temperature onset threshold for LSR (young: -0.13°C [-0.25, -0.01], older: -0.15°C [-0.30, 0.00], p=0.84) during the pre/post heat stress test. Conclusion: These results suggest that passive heat acclimation improves heat loss capacity in young and older adults. However, age may blunt the increase in whole-body sweat rate that accompanies passive heat acclimation, but not other classical markers of human heat acclimation. Natural Sciences and Engineering Research Council of Canada. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 1023: Cholesterol Sensitivity Of A K+ Channel, Kir2.1 Plays A Role In Weight Maintenance, Energy Distribution, And Akt-dependent Mouse Mesenteric Metabolism

Background: Inwardly Rectifying Potassium Channel 2.1 (Kir2.1) plays a role in the maintenance of membrane potential and is strongly suppressed by membrane cholesterol and diet-induced hypercholesterolemia. Specifically, Kir2.1 is critical for flow-induced vasodilation in mice. To determine the role of cholesterol-induced suppression of Kir2.1 channels in weight maintenance and energy metabolism under high fat diet (HFD) conditions, we generated a CRISPR mouse expressing a cholesterol-insensitive Kir2.1 mutant, Kir2.1 L222I . Objective: In this study, we demonstrate that Kir2.1 L222I has a protective effect against diet induced obesity, induces changes in mesenteric metabolism, and increased respiratory rate. Methods: C57/BL6J (WT) male mice with the Kir2.1 L222I mutation were fed HFD and weighed after 15 weeks. Mouse feeding was assessed using BioDaq and nuclear magnetic resonance (NMR) determined body composition. Techniplast and iWorx metabolic cages were used for fecal and respiratory analysis. Metabolomic analysis was done on mesentery. Results: Initially, WT (n=6) and Kir2.1 L222I (n=7) male mice weighed the same. After 15 weeks on HFD Kir2.1 L222I mice weighed 16% less than WT mice (p=0.003). Kir2.1 L222I mice also had improved body composition with lean-to-fat ratio a statistically significant 69% greater than WT. Changes in body mass do not depend on feeding behavior as there was no difference between Kir2.1 L222I (n=8) and WT (n=6). The Kir2.1 L222I mice do not excrete more feces than WT (n=5) in terms of weight or caloric content. Kir2.1 L222I mice have increased respiration compared to WT as their exchange rate was a statistically significant 14% higher indicating that Kir2.1 L222I mice burn more calories through respiration. Metabolomic pathway analysis did not identify any changes in carbohydrate or mitochondrial metabolism. However, it identified changes in amino acid and lipid metabolism, specifically, methionine and choline metabolites. Conclusions: The Kir2.1 L222I mutation is protective against weight gain and associated changes in body composition in male mice up to 3 months on diet. Increased respiration may explain this protection. Metabolomics indicated an increase in Akt-dependent amino acid and lipid metabolism.

EFFECTS OF DAILY 5-MINUTE ECCENTRIC-BIASED EXERCISES ON PHYSICAL FITNESS, BODY COMPOSITION, CRITICAL HEALTH MARKERS AND WELL-BEING IN SEDENTARY INDIVIDUALS

INTRODUCTION Exercise is fundamental for maintaining and improving health and fitness; however, many individuals do not participate in regular exercise, with perceived lack of time a key barrier. Minimal dose strategies, which reduce weekly exercise volumes to less than recommended guidelines, might improve health outcomes with minimal time investment. However, minimal dose strategies and their effects on health and fitness are still unclear. Therefore, we developed a bodyweight eccentric-biased exercise program consisting of 4 exercises (1 set of 10 repetitions each), which took just 5-min to complete, and investigated the effects of the program performed daily for 4 weeks on health and fitness outcomes in sedentary individuals. METHODS We recruited 22 healthy but sedentary individuals (32 – 69 years) whose daily steps were <5000. Participants completed a two-week control period, followed by a 4-week daily exercise intervention. Muscular strength, physical fitness, body composition and critical health markers were assessed before (PRE-1) and after the control period (PRE-2), as well as after the intervention (POST). RESULTS Participants adhered to the exercise program >90%. No significant changes in any measures were observed from PRE-1 to PRE-2. Following the exercise intervention, no significant changes in body mass, bone mineral density, fat mass, lean mass, heart rate, blood pressure, grip strength, squat jump or countermovement jump were evident. However, isometric mid-thigh pull, representing lower limb muscle strength (13%), push-ups (42%) and sit-ups (44%), representing upper body strength and sit and reach, representing flexibility (12%) increased significantly (P<0.05), and the increase in heart rate from a 3-minute step test was attenuated (8%) from PRE-2 to POST (P<0.05). Finally, mental health assessed by SF-36 significantly improved (15%) (P<0.05). CONCLUSION These results suggest that the 5-min eccentric exercise program was effective for improving physical fitness and mental health of sedentary individuals when performed every day for 4 weeks.