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Blog – Page 421

By Sher Bahadur Poudel & Shoshana Yakar et al.

Several mouse lines with congenital growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis disruption have shown improved health and extended lifespan. The current study investigated how inactivating this axis, specifically during aging, impacts the healthspan. We used a tamoxifen-inducible global GH receptor (GHR) knockout mouse model starting at 12 months and followed the mice until 24 months of age (iGHRKO12–24 mice). We found sex-and tissue-specific effects, with some being pro-aging and others anti-aging. Measuring an array of cytokines in serum revealed that inactivation of the GH/IGF-1 axis at 12 months did not affect systemic inflammation during aging. On the other hand, hypothalamic inflammation was significantly reduced in iGHRKO12–24 mice, evidenced by GFAP+ (glial fibrillary acidic protein, a marker of astrocytes) and Iba-1+ (a marker for microglia). Liver RNAseq analysis indicated feminization of the male transcriptome, with significant changes in the expression of monooxygenase, sulfotransferase, and solute-carrier-transporter gene clusters. Finally, we found impaired bone morphology, more pronounced in male iGHRKO12–24 mice and correlated with GH/IGF-1 inactivation onset age. We conclude that inhibiting the GH/IGF-1 axis during aging only partially preserves the beneficial healthspan effects observed with congenital GH deficiency.

Inactivating the GH axis during aging has sex-and tissue-specific effects on healthspan. Deleting the GH receptor (GHR) in the entire body at 12 months of age led to feminizing the male liver transcriptome, significantly altering the expression of p450 and sulfotransferase gene clusters. While GHR deletion during aging did not impact systemic inflammation, it was linked to reduced hypothalamic inflammation. Additionally, we observed impaired bone morphology, particularly in male mice, which correlated with the age at which GH/IGF-1 inactivation began. Our findings suggest that inhibiting the GH axis during aging only partially maintains the beneficial healthspan effects seen with congenital GH deficiency.

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When the brain is observed through imaging, there is a lot of “noise,” which is spontaneous electrical activity that comes from a resting brain. This appears to be different from brain activity that comes from sensory inputs, but just how similar—or different—the noise is from the signal has been a matter of debate.

New research led by a team at the University of Tokyo further untangles the relationship between internally generated noise and stimulus-related patterns in the brain, and finds that the patterns of spontaneous activity and stimulus-evoked response are similar in lower visual areas of the cerebral cortex, but gradually become independent, or “orthogonal,” as one moves from lower to higher visual areas.

The findings not only enhance our understanding of the mechanism that enables the brain to distinguish between signal and noise, but could also provide clues for developing noise-resistant incorporating a mechanism similar to that found in the biological brain. The study is published in the journal Nature Communications.

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A new study from Washington University School of Medicine in St. Louis describes an innovative method of analyzing mammograms that significantly improves the accuracy of predicting the risk of breast cancer development over the following five years.

Using up to three years of previous mammograms, the new method identified individuals at high risk of developing 2.3 times more accurately than the standard method, which is based on questionnaires assessing clinical risk factors alone, such as age, race and family history of breast cancer.

The study is published Dec. 5 in JCO Clinical Cancer Informatics.

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Cell–cell alignment and a background of stationary cells together shape the emergence of cellular clusters in a primary tumor.

In a cancer patient, tumor cells that circulate throughout the body in clusters pose a greater threat of metastasis than those that circulate individually. Those clusters are thought to come together while the cells are still within the primary tumor, but researchers still don’t understand the formation mechanism. Quirine Braat at Eindhoven University of Technology in the Netherlands and her colleagues have now used computer simulations to identify some of the factors at play [1].

The team used a computational lattice model of cells and tissues (the cellular Potts model) to examine a 2D layer of two types of cells—one motile (able to move) and one nonmotile. The tendency of the motile cells to migrate was represented in the model by an external force applied to each one. For a given cell, this force could align strongly or weakly with the forces acting on its neighboring cells.

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A trio of archaeologists at the University of Cambridge, in the U.K. conducted a study of hundreds of papers outlining research into hunter–gatherer societies, finding that people in such groups engage in a variety of physical activities. George Brill, Marta Mirazon-Lahr and Mark Dyble published their paper in the journal Proceedings of the Royal Society B: Biological Sciences.

For much of history, male physical and athletic prowess has been considered to be important, while female physical prowess has been mostly overlooked. In this new study, the research team wondered if female physical prowess has also been overlooked in a hunter–gatherer context.

To find out, they conducted a study focusing on research efforts into hunter–gatherer societies—both those in the past and those still in existence today. In all, they looked at more than 900 papers, focusing most specifically on physical or athletic activities of people of both genders.

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