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Human Sperm Retains Viability in Outer Space Conditions: Researchers

The study was presented at an annual meeting of European Society of Human Reproduction and Embryology in Vienna, Austria

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Each sperm has 37.5MB of DNA information in it.
Each sperm has 37.5MB of DNA information in it.

Researchers have found that human sperm retains its complete viability within the different gravitational conditions found in outer space.

The results could be a huge boost to zillionaires like Amazon founder Jeff Bezos who see the “colonisation” of space as an answer to the Earth’s ever threatened resources.

“If the number of space missions increases in the coming years, and are of longer duration, it is important to study the effects of long-term human exposure to space in order to face them,” said Montserrat Boada from Dexeus Women’s Health in Barcelona, whose group worked with microgravity engineers from the Polytechnic University of Barcelona.

“It’s not unreasonable to start thinking about the possibility of reproduction beyond the Earth,” Boada said.

The study was performed using a small aerobatic training aircraft (CAP10), which can provide short-duration hypogravity exposure.

The plane executed a series of 20 parabolic manoeuvres, providing eight seconds of microgravity for each parabola.

Overall, 10 sperm samples obtained from 10 healthy donors were analysed after exposure to the different microgravities found in space and ground gravity.

To overcome regulatory constraints and increase donor numbers, sperm banks in the UK and Australia began to market the act of donating sperm as a confirmation of masculinity. Pixabay

The sperm analysis comprised a full range of measurements currently performed for fertility testing — concentration, motility, vitality, morphology and DNA fragmentation — and results found no difference whatsoever in any of the parameters between the microgravity space samples and the control group samples from Earth.

Indeed, there was 100 per cent concordance in DNA fragmentation rate and vitality, and 90 per cent concordance in sperm concentration and motility, said Boada.

These minor differences, she added, “were more probably related to heterogeneity of the sperm sample than to the effect of exposure to different gravity conditions”.

Boada described this as a preliminary study and her group will now move on to validate the results and then to larger sperm samples, longer periods of microgravity and even fresh sperm.

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One reason for using frozen sperm in this study was the known effect of radiation on fresh sperm, Boada noted.

“Radiation impairs the quality and viability of human sperm, and these effects are expected to be greater on fresh sperm than on frozen samples,” she said.

The study was presented at an annual meeting of European Society of Human Reproduction and Embryology in Vienna, Austria. (IANS)

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Heart Rate Gets Altered in Space But Returns to Normal on Earth

Upon return to Earth, space-flown heart cells show normal structure and morphology

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Heart Rate
Relatively little is known about the role of microgravity in influencing human Heart Rate at the cellular level. Pixabay

Heart Rate gets altered in space but return to normal within 10 days on Earth, say researchers who examined cell-level cardiac function and gene expression in human heart cells cultured aboard the International Space Station (ISS) for 5.5 weeks.

Exposure to microgravity altered the expression of thousands of genes, but largely normal patterns of gene expression reappeared within 10 days after returning to Earth, according to the study published in the journal Stem Cell Reports.

“We’re surprised about how quickly human heart muscle cells are able to adapt to the environment in which they are placed, including microgravity,” said senior study author Joseph C. Wu from Stanford University.

These studies may provide insight into cellular mechanisms that could benefit astronaut health during long-duration spaceflight, or potentially lay the foundation for new insights into improving heart health on Earth.

Past studies have shown that spaceflight induces physiological changes in cardiac function, including reduced heart rate, lowered arterial pressure, and increased cardiac output.

But to date, most cardiovascular microgravity physiology studies have been conducted either in non-human models or at tissue, organ, or systemic levels.

Relatively little is known about the role of microgravity in influencing human cardiac function at the cellular level.

Heart Rate
Heart Rate gets altered in space but return to normal within 10 days on Earth, say researchers who examined cell-level cardiac function and gene expression in human heart cells cultured aboard the International Space Station (ISS) for 5.5 weeks. Pixabay

To address this question, the research team studied human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). They generated hiPSC lines from three individuals by reprogramming blood cells, and then differentiated them into heart cells.

Beating heart cells were then sent to the ISS aboard a SpaceX spacecraft as part of a commercial resupply service mission.

Simultaneously, ground control heart cells were cultured on Earth for comparison purposes.

Upon return to Earth, space-flown heart cells showed normal structure and morphology. However, they did adapt by modifying their beating pattern and calcium recycling patterns.

In addition, the researchers performed RNA sequencing of heart cells harvested at 4.5 weeks aboard the ISS, and 10 days after returning to Earth.

These results showed that 2,635 genes were differentially expressed among flight, post-flight, and ground control samples.

Most notably, gene pathways related to mitochondrial function were expressed more in space-flown heart cells.

A comparison of the samples revealed that heart cells adopt a unique gene expression pattern during spaceflight, which reverts to one that is similar to groundside controls upon return to normal gravity, the study noted.

Heart Rate
Past studies have shown that spaceflight induces physiological changes in cardiac function, including reduced Heart Rate, lowered arterial pressure, and increased cardiac output. Pixabay

According to Wu, limitations of the study include its short duration and the use of 2D cell culture.

In future studies, the researchers plan to examine the effects of spaceflight and microgravity using more physiologically relevant hiPSC-derived 3D heart tissues with various cell types, including blood vessel cells.

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“We also plan to test different treatments on the human heart cells to determine if we can prevent some of the changes the heart cells undergo during spaceflight,” Wu said. (IANS)