Analysis of sex-based differences in energy substrate utilization during moderate-intensity aerobic exercise.

PURPOSE: To explore sex-based differences in energy substrate utilization during moderate-intensity aerobic exercise; to identify the underpinning candidate physiological mechanisms. METHODS: Three databases were searched from inception to August 2020. Pertinent studies quantifying the utilization of substrates during moderate aerobic exercise in healthy men and reproductive-age women were considered. Studies conducted on sedentary/recreationally active and athletic populations were included and analyzed separately. RESULTS: Thirty-five studies entered the meta-analysis (21 in sedentary/recreationally active, 14 in athletic populations). Compared to women, the respiratory exchange ratio was significantly higher both in sedentary (mean difference, MD: + 0.03; p < 0.00001) and athletic men (MD: + 0.02; p < 0.0001). Greater carbohydrate oxidation was observed both in sedentary (standardized MD, SMD: 0.53; p = 0.006) and athletic men (SMD: 1.24; p < 0.00001). Regarding lipid substrates, sedentary men oxidized less fat than women (SMD:  - 0.77; p = 0.0002), while no sex-based differences in fat oxidation were observed in athletes (SMD: 0.06; p = 0.77). Paucity of data prevented robust meta-analyses for protein sources. Sex hormones and different adrenergic activation were the most cited mechanisms to discuss sex-based differences. CONCLUSIONS: Meta-analyses confirmed that men display greater reliance on carbohydrates while women rely more on lipids to sustain moderate aerobic exercise. The latter finding was not confirmed in athletes, a novel aspect of the present study. Mechanistically driven research is needed to further dissect the physiological underpinnings of sex differences in substrate utilization during aerobic exercise, especially for proteins, which are still less investigated than other substrates.

Energy Expenditure and Oxygen Consumption During Activities of Daily Living in People With Multiple Sclerosis and Healthy Subjects: An Ecological Approach to Estimate Real-Life Fatigue and Fatigability.

OBJECTIVE: To compare oxygen consumption and energy expenditure (EE) of the activities of daily living (ADL) in people with multiple sclerosis (PwMS) and healthy subjects. DESIGN: Cross-sectional observational study. SETTING: Outpatient care facilities. PARTICIPANTS: Twenty-four moderately impaired PwMS and 21 healthy controls (N=45). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Oxygen consumption, EE rate, and total EE assessed by portable open-circuit spirometry during the accomplishment of a comprehensive set of 14 ADL. Body composition was also assessed with bioelectrical impedance analysis. Body cell mass was used to normalize metabolic rates between groups. RESULTS: PwMS exhibited significantly higher oxygen consumption than controls in transfer and mobility tasks (walking with stairs: +10.4%, P=.04; without stairs: +15.2%, P=.002; driving: +10.4%, P=.04) and higher EE rates for walking (+13.6%, P=.01). ADL completion took significantly longer in PwMS. Consequently, when total EE to complete each ADL was considered, PwMS used significantly more energy in 10 of the 14 ADL. Of these, "climb stairs" and walking with or without stairs showed the largest differences (+100%, +99.5%, +79.3%, respectively; all P values<.0005), followed by "dressing" (+48.8%; P=.002), "laundry" (+41.7%; P=.007), and "shopping" (+40.1%; P=.003). CONCLUSIONS: Moderately disabled PwMS display oxygen consumption and EE rates during ADL that are comparable to those of matched healthy subjects, except for the activities that involve walking. Although metabolic rates were not different for the majority of ADL, PwMS showed higher total EE to complete the same activities at a comparable work intensity, which may contribute to the burden of "real-life" tiredness and fatigue typically described in this population. Importantly, the subjective Modified Fatigue Impact Scale score significantly correlated to EE and oxygen consumption of selected ADL, such as "make a bed," "driving," "clean surfaces," and "climb stairs." The joint employment of open-circuit spirometry during ADL and body composition analysis allows an accurate metabolic characterization of PwMS, who frequently complain of fatigue.

Acanthamoeba proteases contribute to macrophage activation through PAR1 , but not PAR2.

AIM: Acanthamoeba infections are characterized by an intense localized innate immune response associated with an influx of macrophages. Acanthamoeba protease production is known to affect virulence. Herein, the ability of Acanthamoeba trophozoite proteases, of either the laboratory Neff strain or a recently isolated clinical strain, to stimulate IL-12 and IL-6 and to activate protease-activated receptors, PAR1 and PAR2 expressed on murine macrophages, was investigated. METHOD AND RESULTS: Using selected protease inhibitors, leupeptin and E64, we showed that Acanthamoeba proteases can stimulate IL-12 and IL-6 by murine macrophages. Subsequently, using specific antagonists to inhibit PAR1 , and bone marrow-derived macrophages from PAR2 gene-deficient mice, we demonstrate that PAR1 , but not PAR2 contributes to macrophage IL-12 production in response to Acanthamoeba. In contrast, Acanthamoeba-induced IL-6 production is PAR1 and PAR2 independent. CONCLUSION: This study shows for the first time the involvement of PARs, expressed on macrophages, in the response to Acanthamoeba trophozoites and might provide useful insight into Acanthamoeba infections and their future treatments.

Acanthamoeba Activates Macrophages Predominantly through Toll-Like Receptor 4- and MyD88-Dependent Mechanisms To Induce Interleukin-12 (IL-12) and IL-6.

Acanthamoeba castellanii is a ubiquitous free-living amoeba with a worldwide distribution that can occasionally infect humans, causing particularly severe infections in immunocompromised individuals. Dissecting the immunology of Acanthamoeba infections has been considered problematic due to the very low incidence of disease, despite the high exposure rates. While macrophages are acknowledged as playing a significant role in Acanthamoeba infections, little is known about how this facultative parasite influences macrophage activity. Therefore, in this study we investigated the effects of Acanthamoeba on the activation of resting macrophages. Consequently, murine bone marrow-derived macrophages were cocultured with trophozoites of either the laboratory Neff strain or a clinical isolate of A. castellaniiIn vitro real-time imaging demonstrated that trophozoites of both strains often established evanescent contact with macrophages. Both Acanthamoeba strains induced a proinflammatory macrophage phenotype characterized by the significant production of interleukin-12 (IL-12) and IL-6. However, macrophages cocultured with the clinical isolate of Acanthamoeba produced significantly less IL-12 and IL-6 than the Neff strain. The utilization of macrophages derived from MyD88-, TRIF-, Toll-like receptor 2 (TLR2)-, TLR4-, and TLR2/4-deficient mice indicated that Acanthamoeba-induced proinflammatory cytokine production was through MyD88-dependent, TRIF-independent, TLR4-induced events. This study shows for the first time the involvement of TLRs expressed on macrophages in the recognition of and response to Acanthamoeba trophozoites.

Acanthamoeba castellanii Genotype T4 Stimulates the Production of Interleukin-10 as Well as Proinflammatory Cytokines in THP-1 Cells, Human Peripheral Blood Mononuclear Cells, and Human Monocyte-Derived Macrophages.

Free-living amoebae of the genus Acanthamoeba can cause severe and chronic infections in humans, mainly localized in immune privileged sites, such as the brain and the eye. Monocytes/macrophages are thought to be involved in Acanthamoeba infections, but little is known about how these facultative parasites influence their functions. The aim of this work was to investigate the effects of Acanthamoeba on human monocytes/macrophages during the early phase of infection. Here, THP-1 cells, primary human monocytes isolated from peripheral blood, and human monocyte-derived macrophages were either coincubated with trophozoites of a clinical isolate of Acanthamoeba (genotype T4) or stimulated with amoeba-derived cell-free conditioned medium. Production of proinflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin-6 [IL-6], and IL-12), anti-inflammatory cytokine (IL-10), and chemokine (IL-8) was evaluated at specific hours poststimulation (ranging from 1.5 h to 23 h). We showed that both Acanthamoeba trophozoites and soluble amoebic products induce an early anti-inflammatory monocyte-macrophage phenotype, characterized by significant production of IL-10; furthermore, challenge with either trophozoites or their soluble metabolites stimulate both proinflammatory cytokines and chemokine production, suggesting that this protozoan infection results from the early induction of coexisting, opposed immune responses. Results reported in this paper confirm that the production of proinflammatory cytokines and chemokines by monocytes and macrophages can play a role in the development of the inflammatory response during Acanthamoeba infections. Furthermore, we demonstrate for the first time that Acanthamoeba stimulates IL-10 production in human innate immune cells, which might both promote the immune evasion of Acanthamoeba and limit the induced inflammatory response.

Stratification of Amniotic Fluid Cells and Amniotic Fluid by Sex Opens Up New Perspectives on Fetal Health.

Amniotic fluid is essential for fetus wellbeing and is used to monitor pregnancy and predict fetal outcomes. Sex affects health and medicine from the beginning of life, but knowledge of its influence on cell-depleted amniotic fluid (AF) and amniotic fluid cells (AFCs) is still neglected. We evaluated sex-related differences in AF and in AFCs to extend personalized medicine to prenatal life. AFCs and AF were obtained from healthy Caucasian pregnant women who underwent amniocentesis at the 16th-18th week of gestation for advanced maternal age. In the AF, inflammation biomarkers (TNFα, IL6, IL8, and IL4), malondialdehyde, nitrites, amino acids, and acylcarnitines were measured. Estrogen receptors and cell fate (autophagy, apoptosis, senescence) were measured in AFCs. TNFα, IL8, and IL4 were higher in female AF, whereas IL6, nitrites, and MDA were similar. Valine was higher in male AF, whereas several acylcarnitines were sexually different, suggesting a mitochondrial involvement in establishing sex differences. Female AFCs displayed higher expression of ERα protein and a higher ERα/ERß ratio. The ratio of LC3II/I, an index of autophagy, was higher in female AFCs, while LC3 gene was similar in both sexes. No significant sex differences were found in the expression of the lysosomal protein LAMP1, while p62 was higher in male AFCs. LAMP1 gene was upregulated in male AFCs, while p62 gene was upregulated in female ones. Finally, caspase 9 activity and senescence linked to telomeres were higher in female AFCs, while caspase 3 and ß-galactosidase activities were similar. This study supports the idea that sex differences start very early in prenatal life and influence specific parameters, suggesting that it may be relevant to appreciate sex differences to cover knowledge gaps. This might lead to improving the diagnosis of risk prediction for pregnancy complications and achieving a more satisfactory monitoring of fetus health, even preventing future diseases in adulthood.

Sex-Based Differences in Oxygen Cost of Walking and Energy Equivalents in Minimally Disabled Individuals With Multiple Sclerosis and Controls.

Background: Elevated oxygen cost of walking and energy equivalents are reported for highly and moderately disabled individuals with multiple sclerosis (MS). However, less is known about minimally impaired individuals. Moreover, no sex-based data on the metabolic rates of individuals with MS are available. In this cross-sectional study, the metabolic rates and temporospatial parameters of gait during overground walking in minimally disabled individuals with MS versus matched controls were quantified and whether sex-based differences occur was examined. Methods: Sixty-nine minimally impaired adults with MS (37, relapsing-remitting MS [RRMS]; 32, clinically isolated syndrome [CIS]) and 25 matched controls completed two 6-minute walking bouts at comfortable and fast speeds. The oxygen cost of walking, energy equivalents, and respiratory exchange ratio were recorded through breath-by-breath open-circuit spirometry. Gait analysis was performed via a portable electronic walkway. Results: At comfortable but not at fast speed, men with RRMS showed higher oxygen cost of walking than men with CIS (+17.9%, P = .04) and male controls (+21.3%, P = .03). In the RRMS group, men showed higher oxygen cost of walking (+19.2%, P = .04) and energy equivalents (+19.2%, P = .02) than women. Elevated oxygen cost of walking and energy equivalents in men were paralleled by significantly larger base of support and step time asymmetry during walking. Conclusions: Metabolic demands are elevated while walking in minimally disabled individuals with RRMS. Furthermore, higher energy demands occur in men, probably due to increased step symmetry and base of support. Clinicians are advised to follow energy expenditure metrics collected while walking because they can indicate a decrease in fitness, even in the early phase of MS.

Direct-to-Consumer Nutrigenetics Testing: An Overview.

At present, specialized companies offering genetic testing services without the involvement of clinicians are growing; this development is a direct consequence of the significant decrease in genotyping and sequencing costs. Online companies offer predictions about the risk of developing complex diseases during one's life course, and they offer suggestions for personal lifestyle. Several companies have been created that provide nutrigenetics services; these companies suggest dietary indications-a central issue in the prevention and etiopathogenesis of specific diseases-based on one's personal genetic background. Dietary patterns are defined on the basis of a limited set of genetic markers. In this article, we analyze the online nutrigenetics services offered by 45 companies worldwide, to obtain an overall picture of the costs, the types of nutritional traits considered and the level of scientific precision of the services proposed. Our analysis clearly highlights the need for specific guidelines, in order to ensure a set of minimum quality standards for the nutrigenetics services offered to the customer.

Free-Living Amoebae Keratitis.

PURPOSE: To describe the diagnostic and clinical features and treatment results in 43 consecutive patients with microbiologically proven free-living amoebae (FLA) keratitis. METHODS: In this hospital-based, prospective case series, corneal scrapings from 43 patients with presumed amoebic keratitis were plated on nonnutrient agar. Amoebic isolates were identified morphologically and by the polymerase chain reaction. All patients with culture-proven FLA keratitis were treated with polyhexamethylene biguanide (PHMB) 0.02% eye drops. RESULTS: Forty-three corneal scrapings from 43 patients were found to be culture positive for FLA; 41 (95%) were from contact lens wearers and 2 (5%) were from noncontact lens wearers. Microscopic examination identified 4 Acanthamoeba spp, 24 Hartmannella spp, 12 vahlkampfiid amoebae, and 3 mixed infections with Hartmannella/vahlkampfiid amoebae. Morphological results were confirmed by the polymerase chain reaction. Patients with Acanthamoeba, Hartmannella, and vahlkampfiid keratitis had indistinguishable clinical features. In 38 eyes with keratitis at an early stage, treatment with PHMB 0.02% eye drops was fully successful. In 5 patients with advanced keratitis, topical PHMB 0.02% controlled the infection, but all of them developed a central corneal scar with visual deterioration. CONCLUSIONS: Acanthamoeba is not the only cause of amoebic keratitis, because this condition may also be caused by other FLA, such as Hartmannella and vahlkampfiid amoebae. This finding is epidemiologically interesting, suggesting a possible different geographical prevalence of the different FLA responsible for keratitis. Early diagnosis and proper antiamoebic treatment are crucial to yielding a cure.

The Acanthamoeba shikimate pathway has a unique molecular arrangement and is essential for aromatic amino acid biosynthesis.

The shikimate pathway is the only known biosynthetic route for de novo synthesis of aromatic compounds. It is described as an ancient eukaryotic innovation that has been retained in a subset of eukaryotes, replaced in plants through the acquisition of the chloroplast, but lost in many including humans. Herein, we demonstrate that Acanthamoeba castellanii possesses the shikimate pathway by biochemical and a combination of bioinformatics and molecular biological methods. The growth of A. castellanii (Neff strain and a recently isolated clinical specimen, both T4 genotypes) is inhibited by glyphosate [N-(phosphonomethyl) glycine], an inhibitor of EPSP synthase and the addition of phenylalanine and tryptophan, which are dependent on the shikimate pathway, rescued A. castellanii from glyphosate indicating that glyphosate was specific in action. A. castellanii has a novel complement of shikimate pathway enzymes including unique gene fusions, two Type I and one Type II DAHP synthases (for which their likely sensitivities to feedback inhibition by phenylalanine, tyrosine and tryptophan has been modelled) and a canonical chorismate synthase. The shikimate pathway in A. castellanii therefore has a novel molecular arrangement, is required for amino acid biosynthesis and represents an attractive target for antimicrobials.