Medical Bulletin 03 January/ 2025 - Video

Here are the top medical news for the day:

Link Between Smoking and Chronic Kidney Disease?

A recent study published in Health Data Science shed light on the complex relationship between smoking behavior and chronic kidney disease (CKD). The researchers concluded that their analysis does not suggest a causal effect of smoking on chronic kidney disease. Using data from over 500,000 participants in the UK Biobank cohort, the researchers conducted both traditional observational studies and advanced Mendelian randomization (MR) analyses to explore whether smoking behavior directly contributes to chronic kidney disease.

While observational studies indicated a positive association between smoking status and the risk of chronic kidney disease, the Mendelian randomization analysis revealed no evidence of a causal relationship. Specifically, genetic variants associated with smoking behavior did not show a direct causal effect on chronic kidney disease development.

These findings suggest that the previously observed associations in observational studies might be influenced by confounding factors rather than a direct causal link. Researchers propose that factors such as diabetes and hypertension may act as mediators in the relationship between smoking and chronic kidney disease .

“Our results emphasize the need for more detailed mediation analyses on large-scale, multi-ethnic datasets to fully understand the interplay between smoking and chronic kidney disease,” said Professor Luxia Zhang. “While smoking remains a significant health risk factor, its direct role in chronic kidney disease development requires further investigation.”

Reference: Zhilong Zhang, Feifei Zhang, Xiaomeng Zhang, Lanlan Lu, Luxia Zhang. Association of Smoking with Chronic Kidney Disease Stages 3 to 5: A Mendelian Randomization Study. Health Data Sci. 2024;4:0199.DOI:10.34133/hds.0199

Study Highlights How Aging May Alter Brain Cell Genetic Activity

Based on new brain mapping research, scientists have discovered that not all cell types in the brain age in the same way. They found that some cells, such as a small group of hormone-controlling cells, may undergo more age-related changes in genetic activity than others. The results are published in Nature.

Scientists used advanced genetic analysis tools to study individual cells in the brains of 2-month-old “young” and 18-month-old “aged” mice. For each age, researchers analysed the genetic activity of a variety of cell types located in 16 different broad regions — constituting 35% of the total volume of a mouse brain.

Like previous studies, the initial results showed a decrease in the activity of genes associated with neuronal circuits. These decreases were seen in neurons, the primary circuitry cells, as well as in “glial” cells called astrocytes and oligodendrocytes, which can support neural signaling by controlling neurotransmitter levels and electrically insulating nerve fibers. In contrast, aging increased the activity of genes associated with the brain’s immunity and inflammatory systems, as well as brain blood vessel cells.

Further analysis helped spot which cell types may be the most sensitive to aging. The cells that appeared to be the most sensitive to aging surround the third ventricle.

Reference: Jin, K., Yao, Z., van Velthoven, C.T.J. et al. Brain-wide cell-type-specific transcriptomic signatures of healthy ageing in mice. Nature (2025). https://doi.org/10.1038/s41586-024-08350-8

Novel Injectable Hydrogel for Bone Regeneration and Adhesion: Study Finds

A research team has developed an innovative injectable adhesive hydrogel for bone regeneration. This hydrogel utilizes harmless visible light to simultaneously achieve cross-linking and mineralization without the need for bone grafts. The research was recently published online in Biomaterials.

Existing injectable hydrogels face challenges such as difficulty in maintaining their shape within the body and limited adhesive strength. Moreover, traditional methods using bone grafts with adhesive materials often fail to achieve simultaneous "bone regeneration" and "adhesion."

The researchers have introduced a novel system that addresses these limitations. This new hydrogel system employs visible light—safe for the human body—to facilitate cross-linking, where the main components of the hydrogel bond and harden, and to simultaneously boost mineralization where bone-building minerals like calcium and phosphate form within the hydrogel.

The newly developed hydrogel precursor comprises alginate, RGD peptide-containing mussel adhesive protein, calcium ions, phosphonodiols, and a photoinitiator. The coacervate-based formulation, which is immiscible in water, ensures that the hydrogel retains its shape and position after injection into the body. Upon visible light irradiation, cross-linking occurs, and amorphous calcium phosphate, which functions as a bone graft material, is simultaneously formed. This eliminates the need for separate bone grafts or adhesives, enabling the hydrogel to provide both bone regeneration and adhesion.

In experiments using animal models with femoral bone defects, the hydrogel was successfully injected, adhered accurately, and effectively delivered components essential for bone regeneration.

Professor Cha commented, "The injectable hydrogel system for bone regeneration developed by our research team represents an innovative alternative to conventional complex treatments for bone diseases and will greatly advance bone tissue regeneration technology."

Reference: Yun, J., Woo, H. T., Lee, S., & Cha, H. J. (2025). Visible light-induced simultaneous bioactive amorphous calcium phosphate mineralization and in situ crosslinking of coacervate-based injectable underwater adhesive hydrogels for enhanced bone regeneration. Biomaterials, 315, 122948.