Differences in ATP generation via glycolysis and oxidative phosphorylation, and relationships with sperm motility, in mouse species

Mouse sperm produce enough ATP to sustain motility by anaerobic glycolysis and respiration. However, previous studies indicated that an active glycolytic pathway is required to achieve normal sperm function, and identified glycolysis as the main source of ATP to fuel the motility of mouse sperm. All the available evidence has been gathered for the lab mouse, while comparative studies including closely related mouse species have revealed (a) a wide range of variation in sperm motility and ATP production, and (b) that the lab mouse shows comparatively low values in these traits. In this study, we compared the relative reliance on the usage of glycolysis or oxidative phosphorylation as ATP sources for sperm motility between mouse species that exhibit significantly different sperm performance parameters. We found that the sperm of species with higher oxygen consumption/lactate excretion rate ratio were able to produce higher amounts of ATP, achieving higher swimming velocities. Additionally, we show that the species with higher respiration/glycolysis ratio have a higher degree of dependence upon active oxidative phosphorylation. Moreover, we characterize for the first time, two mouse species in which sperm depend on functional oxidative phosphorylation to achieve normal performance. Finally, we discuss that sexual selection through sperm competition could promote adaptations in sperm energetic metabolism tending to increase the usage of oxidative phosphorylation in relation to glycolysis, as this would constitute a more efficient pathway for the generation of ATP (and faster sperm).Peer reviewe

Sperm competition in fluctuating populations of common voles in southern Europe: reversed relationship between relative testes size and density

Resumen de la comunicación presentada en: 7th European Congress of Mammalogy - Stockholm (Sweden), August 17–21 2015Investment in sperm numbers is a key predictor of success in sperm competition and there is usually a positive relationship between sperm competition level and male reproductive effort on ejaculates, which is often measured using relative testes size (RTS). Demographic processes can drasti- cally alter levels of sperm competition and we should expect males to respond to increasing competition risk (RTS increase with density). Here we investigate whether RTS of common voles respond to fluctuations in population density. We evaluated variation of RTS depending on current and recent densities of con- specifics, also taking into account the condition of individual males (fat levels and parasite loads). Contrary to our prediction and in line with recent findings reporting ambiguous results among other vole species, we found a reversed relationship between RTS and density. Our data show that demographic factors can strongly affect RTS and we discuss possible mechanisms to explain these findings.Peer reviewe

Performance of rodent spermatozoa over time is enhanced by increased ATP concentrations: The role of sperm competition

© 2015 by the Society for the Study of Reproduction, Inc. Sperm viability, acrosome integrity, motility, and swimming velocity are determinants of male fertility and exhibit an extreme degree of variation among closely related species. Many of these sperm parameters are associated with sperm ATP content, which has led to predictions of trade-offs between ATP content and sperm motility and velocity. Selective pressures imposed by sperm competition have been proposed as evolutionary causes of this pattern of diversity in sperm traits. Here, we examine variation in sperm viability, acrosome integrity, motility, swimming velocity, and ATP content over time, among 18 species of closely related muroid rodents, to address the following questions: (a) Do sperm from closely related species vary in ATP content after a period of incubation? (b) Are these differences in ATP levels related to differences in other sperm traits? (c) Are differences in ATP content and sperm performance over time explained by the levels of sperm competition in these species? Our results revealed a high degree of interspecific variability in changes in sperm ATP content, acrosome integrity, sperm motility and swimming velocity over time. Additionally, species with high sperm competition levels were able to maintain higher levels of sperm motility and faster sperm swimming velocity when they were incubated under conditions that support sperm survival. Furthermore, we show that the maintenance of such levels of sperm performance is correlated with the ability of sperm to sustain high concentrations of intracellular ATP over time. Thus, sperm competition may have an important role maximizing sperm metabolism and performance and, ultimately, the fertilizing capacity of spermatozoa.Peer Reviewe

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Espermatología en la conservación de especies amenzadas

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología. Esta tesis tiene embargado el acceso al texto completo hasta el 04-08-2023. https://repositorio.uam.es/handle/10486/702468Las biotecnologías reproductivas en las estrategias para la conservación de especies amenazadas facilitan el flujo génico entre poblaciones fragmentadas y contribuyen a mantener la variabilidad genética necesaria para asegurar la viabilidad de las especies. Además, complementan la acción de bancos de recursos genéticos que sirven para ampliar el marco temporal y espacial de la conservación de germoplasma y tejidos somáticos. El desarrollo de biotecnologías reproductivas requiere un conocimiento profundo de la biología reproductiva de cada especie. En particular, conocer las características espermáticas y los factores que afectan a la calidad seminal es esencial para comprender los determinantes de la fertilidad masculina y desarrollar técnicas de reproducción asistida exitosas. En primer lugar, se analizaron los parámetros seminales de gacela Cuvier, gacela dama, gacela dorcas y lince ibérico. Se caracterizaron la morfometría y cinética espermáticas y se examinaron las relaciones entre ellas. Los resultados mostraron que, en las tres especies de gacelas, los espermatozoides con cabezas más pequeñas y elípticas se mueven más rápido y en trayectorias más lineales y progresivas. No encontramos relaciones entre la morfología de los espermatozoides del lince ibérico con parámetros de cinética espermática. La heterogeneidad del eyaculado según la morfometría del espermatozoide de las tres especies de gacela y lince ibérico mostró tres subpoblaciones comunes diferenciadas en tamaño y elipticidad de la cabeza de la célula, longitud de la pieza media del flagelo y longitud de las piezas principal y terminal. La heterogeneidad del eyaculado según las características de natación se evidenció por la presencia de cuatro subpoblaciones espermáticas en el eyaculado de gacela dama, gacela dorcas y lince ibérico, diferenciadas tanto por descriptores de velocidad como de trayectoria. Por otro lado, se examinó la relación entre factores internos, como la variabilidad genética, en las características seminales de las cuatro especies. Asimismo, se examinó el efecto de factores externos, como enfermedades, en el lince ibérico. El análisis interespecífico de las tres especies de gacelas mostró que los espermatozoides de a especie con mayor grado de consanguinidad, la gacela de Cuvier, tenían peor motilidad y mayor porcentaje de morfoanomalías y acrosomas dañados. En el análisis intraespecífico, únicamente en la gacela de Cuvier se apreció una relación significativa e inversa entre consanguinidad y motilidad, lo que sugiere que la calidad seminal se vería afectada a partir de determinado umbral de consanguinidad. La consanguinidad se asoció a espermatozoides con cabezas grandes y redondeadas y flagelos más cortos, además de espermatozoides lentos y menos progresivos. En el lince ibérico, la calidad seminal de machos híbridos, con mayor variabilidad genética, es mejor que la de sus poblaciones parentales endogámicas. La heterocigosidad se relacionó significativa y positivamente con la concentración y número total de espermatozoides, su motilidad y el porcentaje de células morfológicamente normales, así como con un mayor éxito reproductivo. El efecto de la enfermedad renal crónica provocada por hipervitaminosis D afectó a la calidad seminal de los machos en la fase más grave de la enfermedad. Por último, se realizó un ensayo para desarrollar métodos que permitan conservar espermatozoides de lince ibérico en refrigeración para su uso en transporte e inseminación artificial. Se evaluaron varios tratamientos en tres tempera turas (22ºC, 15ºC y 5ºC) y tres medios de incubación (Ham’s F10, TEST con y sin glicerol). Los resultados mostraron que es posible mantener la motilidad de los espermatozoides durante 24 horas de manera sencilla y con mejores valores a lo largo del tiempo en los tratamientos a 22ºC en medios Ham’s F10 y TEST sin glicerol y a 15ºC en los medios TEST con y sin glicerol.Peer reviewe

Espermatología en la conservación de especies amenzadas

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología. Fecha de Lectura: 04-02-2022Esta tesis tiene embargado el acceso al texto completo hasta el 04-08-202

Immunocompromised patients with acute respiratory distress syndrome: Secondary analysis of the LUNG SAFE database

Background: The aim of this study was to describe data on epidemiology, ventilatory management, and outcome of acute respiratory distress syndrome (ARDS) in immunocompromised patients. Methods: We performed a post hoc analysis on the cohort of immunocompromised patients enrolled in the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE) study. The LUNG SAFE study was an international, prospective study including hypoxemic patients in 459 ICUs from 50 countries across 5 continents. Results: Of 2813 patients with ARDS, 584 (20.8%) were immunocompromised, 38.9% of whom had an unspecified cause. Pneumonia, nonpulmonary sepsis, and noncardiogenic shock were their most common risk factors for ARDS. Hospital mortality was higher in immunocompromised than in immunocompetent patients (52.4% vs 36.2%; p &lt; 0.0001), despite similar severity of ARDS. Decisions regarding limiting life-sustaining measures were significantly more frequent in immunocompromised patients (27.1% vs 18.6%; p &lt; 0.0001). Use of noninvasive ventilation (NIV) as first-line treatment was higher in immunocompromised patients (20.9% vs 15.9%; p = 0.0048), and immunodeficiency remained independently associated with the use of NIV after adjustment for confounders. Forty-eight percent of the patients treated with NIV were intubated, and their mortality was not different from that of the patients invasively ventilated ab initio. Conclusions: Immunosuppression is frequent in patients with ARDS, and infections are the main risk factors for ARDS in these immunocompromised patients. Their management differs from that of immunocompetent patients, particularly the greater use of NIV as first-line ventilation strategy. Compared with immunocompetent subjects, they have higher mortality regardless of ARDS severity as well as a higher frequency of limitation of life-sustaining measures. Nonetheless, nearly half of these patients survive to hospital discharge. Trial registration: ClinicalTrials.gov, NCT02010073. Registered on 12 December 2013

Immunocompromised patients with acute respiratory distress syndrome : Secondary analysis of the LUNG SAFE database

The aim of this study was to describe data on epidemiology, ventilatory management, and outcome of acute respiratory distress syndrome (ARDS) in immunocompromised patients. Methods: We performed a post hoc analysis on the cohort of immunocompromised patients enrolled in the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE) study. The LUNG SAFE study was an international, prospective study including hypoxemic patients in 459 ICUs from 50 countries across 5 continents. Results: Of 2813 patients with ARDS, 584 (20.8%) were immunocompromised, 38.9% of whom had an unspecified cause. Pneumonia, nonpulmonary sepsis, and noncardiogenic shock were their most common risk factors for ARDS. Hospital mortality was higher in immunocompromised than in immunocompetent patients (52.4% vs 36.2%; p < 0.0001), despite similar severity of ARDS. Decisions regarding limiting life-sustaining measures were significantly more frequent in immunocompromised patients (27.1% vs 18.6%; p < 0.0001). Use of noninvasive ventilation (NIV) as first-line treatment was higher in immunocompromised patients (20.9% vs 15.9%; p = 0.0048), and immunodeficiency remained independently associated with the use of NIV after adjustment for confounders. Forty-eight percent of the patients treated with NIV were intubated, and their mortality was not different from that of the patients invasively ventilated ab initio. Conclusions: Immunosuppression is frequent in patients with ARDS, and infections are the main risk factors for ARDS in these immunocompromised patients. Their management differs from that of immunocompetent patients, particularly the greater use of NIV as first-line ventilation strategy. Compared with immunocompetent subjects, they have higher mortality regardless of ARDS severity as well as a higher frequency of limitation of life-sustaining measures. Nonetheless, nearly half of these patients survive to hospital discharge. Trial registration: ClinicalTrials.gov, NCT02010073. Registered on 12 December 2013