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- Vicente Carrillo, Alejandro, 1989-
(författare)
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Sperm Membrane Channels, Receptors and Kinematics : Using boar spermatozoa for drug toxicity screening
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Internal fertilization usually implies that a spermatozoon, with intact attributes for zygote formation, passes all hurdles during its transport through the female genitalia and reaches the oocyte. During this journey, millions to billions of other spermatozoa perish. Spermatozoa are highly differentiated motile cells without synthetic capabilities. They generate energy via glycolysis and oxidative phosphorylation to sustain motility and to maintain the stability and functionality of their plasma membrane. In vivo, they spend their short lifespan bathing in female genital tract fluids of different origins, or are in vitro exposed to defined media during diverse sperm handling i.e. extension, cryopreservation, in vitro fertilization, etc. Being excitable cells, spermatozoa respond in vivo to various stimuli during pre-fertilization (capacitation, hyperactivation, oocyte location) and fertilization (acrosome reaction, interaction with the oocyte) events, mediated via diverse membrane ion-conducting channels and ligand-gated receptors. The present Thesis has mapped the presence and reactivity (sperm intactness and kinematics) of selected receptors, water and ion channels in ejaculated boar spermatozoa. The final aim was to find a relevant alternative cell type for in vitro bioassays that could ease the early scrutiny of candidate drugs as well as decreasing our needs for experimental animals according to the 3R principles. Spermatozoa are often extended, cooled and thawed to warrant their availability as fertile gametes for breeding or in vitro testing. Such manipulations stress the cells via osmotic variations and hence spermatozoa need to maintain membrane intactness by controlling the exchange of water and the common cryoprotectant glycerol, via aquaporins (AQPs). Both AQPs-7 and -9 were studied for membrane domain changes in cauda- and ejaculated spermatozoa (un-processed, extended, chilled or frozen-thawed). While AQP-9 maintained location through source and handling, thawing of ejaculated spermatozoa clearly relocated the labelling of AQP-7, thus appearing as a relevant marker for non-empirical studies of sperm cryopreservation. Alongside water, spermatozoa interact with calcium (Ca2+) via the main Ca2+ sperm channel CatSper. Increments in intracellular Ca2+ initiate motility hyperactivation and the acrosome reaction. The four subunits of the CatSper channel were present in boar spermatozoa, mediating changes in sperm motility under in vitro capacitation-inducing conditions (increased extracellular Ca2+ availability and bicarbonate) or challenge by the CatSper antagonists mibefradil and NNC 55-0396. Uterine and oviduct fluids are richest in endogenous opioids as β-endorphins during mating and ovulation. Both μ- and δ- opioid receptors were present in boar spermatozoa modulating sperm motility, as in vitro challenge with known agonists (μ: morphine; δ: DPDPE and κ: U 50488) and antagonists (μ: naloxone; δ: naltrindole and κ: nor-binaltrorphimine) showed that the μ-opioid receptor maintained or increased motility while the δ-opioid receptor mediated decreased motility over time. Finally, boar spermatozoa depicted dose-response effects on sperm kinematics and mitochondrial potential following in vitro challenge with 130 pharmacological drugs and toxic compounds as well as with eight known mito-toxic compounds. In conclusion, boar spermatozoa expressing functional water (AQPs-7 and -9) and ion (CatSper 1-4) channels as well as μ- and δ-opioid receptors are able to adapt to stressful environmental variations, capacitation and pharmacological compounds and drug components. Ejaculated sperm suspensions are easily and painlessly obtained from breeding boars, and are suitable biosensors for in vitro drug-induced testing, complying with the 3R principles of reduction and replacement of experimental animals, during early toxicology screening.
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| 2. |
- Wang, Anne, et al.
(författare)
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Androgen receptor polymorphism, testosterone levels, and prognosis in patients with acute myocardial infarction
- 2021
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Ingår i: European Heart Journal Open. - : Oxford University Press (OUP). - 2752-4191. ; 1:2
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Tidskriftsartikel (refereegranskat)abstract
- Aims Low testosterone has been associated with cardiovascular disease in men but with contradictory findings. Testosterone bind to the androgen receptor and polymorphisms of the receptor gene such as CAG repeat length may affect transcriptional activity, possibly mitigating testosterone effects. The aims were to study the CAG repeat length and testosterone levels at four time points following a myocardial infarction (MI) and to analyse possible relationships between CAG repeat length and cardiovascular prognosis. Methods and results Male patients admitted for acute MI (n = 122) from the Glucose in Acute Myocardial Infarction study were included. Blood samples were drawn at four time points (day after admission, at discharge, and at 3 and 12 months post-infarction) for assessment of testosterone levels. Patients were followed for a median of 11.6 years. Cox regression analyses were performed for CAG repeat length by one unit increment and by > vs. <_median for cardiovascular events and all-cause mortality. Median CAG repeat length was 20. There was no difference in testosterone levels at each time point when dividing the cohort into <_ vs. >CAG repeat median (=20). There was no association between CAG repeat length either as a continuous or categorical variable in unadjusted and age-adjusted Cox analyses for cardiovascular events. While CAG >20 was associated with all-cause mortality in unadjusted analyses (hazard ratio 2.19, 95% confidence interval 1.13–4.22; P = 0.02), it did not remain significant following adjustment for age. Conclusion CAG repeat length was not associated with testosterone levels or prognosis in men with acute MI.
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