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Older people in low-population density regions tend to have fewer resources to engage in regular physical activity (PA) compared to their counterparts in urban areas. Moreover, PA assumes different dimensions, and the amount of PA related to each dimension may differ between women and men, predisposing them to different PA practices. Therefore, this cross-sectional study aims to describe the prevalence of barriers to PA, gender differences, and their associations with different PA dimensions. A total of 259 older adults (153 women and 106 men; age, 75.17 ± 8.05 years old) living in the community in the region of Guarda (Portugal) were interviewed face to face to record their sociodemographic characteristics, general health status (comorbidity index and self-reported health), PA behaviour, and barriers to PA. Women were more likely to report "low" income and living alone ( p ≤ 0.05), while men reported a higher negative health status than women ( p < 0.05). Two intrinsic ("Fear of injury" (40.1%) and "Need for rest" (26.3%)) and two extrinsic barriers ("Lack of nearby facilities" (30.5%) and "I don't have transport" (25.6%)) were the most prevalent. For women, age, self-reported health, comorbidity index, and intrinsic and extrinsic barriers were similarly associated with the different PA dimensions. However, only self-reported health and extrinsic barriers were the variables associated with the different PA dimensions in men. Therefore, strategies to promote active ageing in low-population density regions should be focused on reducing intrinsic and extrinsic barriers based on gender and the PA dimension to be achieved.

Introduction: Eccentric exercise has often been reported to result in muscle damage, limiting the muscle potential to produce force. However, understanding whether these adverse consequences extend to a broader, functional level is of apparently less concern. In this study, we address this issue by investigating the acute and delayed effects of supramaximal isotonic eccentric exercise on neuromuscular function and motor performance of knee extensors during tasks involving a range of strength profiles, proprioception, and balance., Methods: Fifteen healthy volunteers (23.2 ± 2.9 years old) performed a unilateral isotonic eccentric exercise of the knee extensors of their dominant lower limb (4 × 10 reps at 120% of one Repetition Maximum (1RM)). The maximum voluntary isometric contraction (MVC), rate of force development (RFD), force steadiness of the knee extensors, as well as knee joint position sense and mediolateral (MLI) and anteroposterior stability (API) of the dominant lower limb, were measured pre-, immediately, and 24 h after the eccentric exercise. The EMG amplitude of the vastus medialis (VM) and biceps femoris (BF) were concomitantly evaluated., Results: MVC decreased by 17.9% immediately after exercise ( P  < 0.001) and remained reduced by 13.6% 24 h following exercise ( P  < 0.001). Maximum RFD decreased by 20.4% immediately after exercise ( P  < 0.001) and remained reduced by 15.5% at 24 h ( P  < 0.001). During the MVC, EMG amplitude of the VM increased immediately after exercise while decreasing during the RFD task. Both values returned to baseline 24 h after exercise. Compared to baseline, force steadiness during submaximal isometric tasks reduced immediately after exercise, and it was accompanied by an increase in the EMG amplitude of the VM. MLI and knee joint position sense were impaired immediately after isotonic eccentric exercise ( P  < 0.05). While MLI returned to baseline values 24 h later, the absolute error in the knee repositioning task did not., Discussion: Impairments in force production tasks, particularly during fast contractions and in the knee joint position sense, persisted 24 h after maximal isotonic eccentric training, revealing that neuromuscular functional outputs were affected by muscle fatigue and muscle damage. Conversely, force fluctuation and stability during the balance tasks were only affected by muscle fatigue since fully recovered was observed 24 h following isotonic eccentric exercise., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (© 2023 Vila-Chã, Bovolini, Francisco, Costa-Brito, Vaz, Rua-Alonso, de Paz, Vieira and Mendonça.)

The choroid plexus (CP) is part of the blood-cerebrospinal fluid barrier (BCSFB) and was recently described as an important component of the circadian clock system. It is the principal source of cerebrospinal fluid (CSF) and responsible for the synthesis and secretion of various neuroprotective peptides including those involved in amyloid-β (Aβ) transport/degradation, contributing to Aβ homeostasis. Inadequate Aβ metabolic clearance and transport across the BCSFB have been associated with circadian dysfunctions in Alzheimer's disease (AD) patients. To investigate whether AD pathology influences Aβ scavengers circadian expression, we collected CP at different time points from an AD mouse model (APP/PS1) (female and male animals, aged 6- and 12-months-old) and analyzed their mRNA expression by Real-time RT-PCR. Only angiotensin-converting enzyme (Ace) expression in 6-month-old female wild-type mice and transthyretin (Ttr) expression in 12-month-old female wild-type mice presented significant rhythmicity. The circadian rhythmicity of Ace and Ttr, prompt us to analyze the involvement of circadian rhythm in Aβ uptake. A human CP papilloma (HIBCPP) cell line was incubated with Aβ-488 and uptake was evaluated at different time points using flow cytometry. Aβ uptake displayed circadian rhythmicity. Our results suggest that AD might affect Aβ scavengers rhythmicity and that Aβ clearance is a rhythmic process possibly regulated by the rhythmic expression of Aβ scavengers., (© 2022 Wiley Periodicals LLC.)

Pharmacoresistance of cancer cells to many drugs used in chemotherapy remains a major challenge for the treatment of cancer. Multidrug resistance transporters, especially ATP-binding cassette (ABC) transporters, are a major cause of cancer drug resistance since they translocate a broad range of drug compounds across the cell membrane, extruding them out of the cells. The regulation of ABC transporters by bitter taste receptors (TAS2Rs), which might be activated by specific bitter tasting compounds, was described in several types of cells/organs, becoming a potential target for cancer therapy. TAS2Rs expression has been reported in many organs and several types of cancer, like breast, ovarian, prostate, and colorectal cancers, where their activation was shown to be involved in various biological actions (cell survival, apoptosis, molecular transport, among others). Moreover, many TAS2Rs' ligands, such as flavonoids and alkaloids, with well-recognized beneficial properties, including several anticancer effects, have been reported as potential adjuvants in cancer therapies. In this review, we discuss the potential therapeutic role of TAS2Rs and bitter tasting compounds in different types of cancer as a possible way to circumvent chemoresistance., Competing Interests: Declaration of competing interest All authors declare that they have no conflict of interests regarding the contents of the article entitled “Bitter taste signalling in cancer”., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

There is a substantial literature gap related to the vascular response to different types of exercise training in middle-aged and older populations. Thus, this scoping review aimed to examine the outcomes of controlled trials testing the long-term effects of exercise interventions on vascular function-related outcomes in middle-aged and older populations. The literature search was conducted following PRISMA guidelines. Data sources: five databases were used (EBSCO, MEDLINE, Web of Science, Science Direct, and Google Scholar). Eligibility criteria: controlled trials, published in the last 10 years, in English, containing well-described exercise interventions, reporting vascular quantitative effects of exercise in middle-aged and older people. A total of 62 publications were included. The studies included distinct types and intensities of exercise and were heterogeneous in volume and frequency. The assessed vascular outcomes also presented considerable variability. Overall, most studies reported positive effects of exercise on vascular function outcomes, regardless of exercise characteristics. Different exercise interventions can be applied to improve vascular function in middle-aged and older adults. Studies on combined and stretching exercises reported encouraging results in improving vascular function. Stretching exercises rise as an effective alternative in promoting vascular function among older adults, while combined exercise delivered promising vascular benefits in both populations.

Prolactin is a polypeptide hormone associated with an extensive variety of biological functions. Among the roles of prolactin in vertebrates, some were preserved throughout evolution. This is the case of its function in the brain, where prolactin receptors, are expressed in different structures of the central nervous system. In the brain, prolactin actions are principally associated with reproduction and parental behavior, and involves the modulation of adult neurogenesis, neuroprotection, and neuroplasticity, especially during pregnancy, thereby preparing the brain to parenthood. Prolactin is mainly produced by specialized cells in the anterior pituitary gland. However, during vertebrate evolution many other extrapituitary tissues do also produce prolactin, like the immune system, endothelial cells, reproductive structures and in several regions of the brain. This review summarizes the relevance of prolactin for brain function, the sources of prolactin in the central nervous system, as well as its local production and secretion. A highlight on the impact of prolactin in human neurological diseases is also provided.

Health-related quality of life (HRQoL) is influenced by several factors, such as living place, physical activity (PA), and functional fitness levels. Evidence shows that functional fitness and PA levels are strongly associated with positive HRQoL, especially in the older population. However, the impact of the living place has not been investigated as an influencing variable in this context. Therefore, this study aimed to investigate the relationship between the HRQoL, PA, and functional fitness of older adults living in rural and urban areas of Portugal. A cross-sectional study was performed with community-dwelling adults aged 65 years and over ( n = 261) living in the city of Guarda. The participants were assessed for sociodemographic, anthropometric, clinical health, HRQoL, PA levels, and functional fitness status. The results showed that rural residents presented higher scores of HRQoL and functional fitness than older individuals living in urban areas. Regression models showed that functional fitness variables influence the HRQoL overall score and mental and physical subcomponents of HRQoL, regardless of the living place. In contrast, PA levels only influenced the HRQoL score in rural residents. The findings suggest that intervention programs to improve the physical health, quality of life, and well-being of the older population need to consider the country's different geographical areas.

Among the more than 300 functions attributed to prolactin (PRL), this hormone has been associated with the induction of neurogenesis and differentiation of olfactory neurons especially during pregnancy, which are essential for maternal behavior. Despite the original hypothesis that PRL enters the central nervous system through a process mediated by PRL receptors (PRLR) at the choroid plexus (CP), recent data suggested that PRL transport into the brain is independent of its receptors. Based on transcriptomic data suggesting that PRL could be expressed in the CP, this work aimed to confirm PRL synthesis and secretion by CP epithelial cells (CPEC). The secretion of PRL and the distribution of PRLR in CPEC were further characterized using an in vitro model of the rat blood-cerebrospinal fluid barrier. RT-PCR analysis of PRL transcripts showed its presence in pregnant rat CP, in CPEC, and in the rat immortalized CP cell line, Z310. These observations were reinforced by immunocytochemistry staining of PRL in CPEC and Z310 cell cytoplasm. A 63-kDa immunoreactive PRL protein was detected by Western blot in CP protein extracts as well as in culture medium incubated with rat pituitary and samples of rat cerebrospinal fluid and serum. Positive immunocytochemistry staining of PRLR was present throughout the CPEC cytoplasm and in the apical and basal membrane of these cells. Altogether, our evidences suggest that CP is an alternative source of PRL to the brain, which might impact neurogenesis of olfactory neurons at the subventricular zone, given its proximity to the CP.