Monocytes’ New Role, Cold Application & Tumour, C. difficile & Cancer

Last Week in Medicine

Photo by National Cancer Institute on Unsplash

It was thought that bacteria entering our body were killed by monocytes in our immune system. But a new study published in Nature shows that rather than killing these bacteria directly, monocytes have a role as a conductor, managing inflammation and healing tissue in that area.

It also maintains this role by producing ghrelin molecules, the appetite hormone. Ghrelin suppresses the formation of excess new vessels in the inflammation area and provides healing after infection.

Kratofil et al. carried out this experiment with mice that they had infected with S. aureus. They also compared the mice with Ccr2 gene, the gene that provides this monocyte accumulation in the skin region, with a mice that lacks the gene. In this genetically deficient mice, they observed swelling in the area, delay in wound healing, and excess formation of new vessels as a result of the lack of monocytes at the infection site.

Cancer cells are the cells that use the most nutrients (glucose) in the body. They already provide the ability to divide much more than other cells with this high glucose. Reducing this glucose uptake for anti-cancer treatments has been considered before.

A study published in Nature has developed a new method of reducing this glucose uptake. Glucose in the blood can be reduced by activation of thermogenesis metabolism in brown adipose tissues (BAT). Seki et al. have tried cold applications to trigger this mechanism.

They showed that glucose uptake was reduced in tumour cell mice as a result of cold-induced BAT activation. In the same study, they also did human studies. They kept six healthy volunteers in a 16°C environment for 2–6 hours a day for 14 days. With PET scans, they determined that BAT activation occurred significantly.

They kept an 18-year-old patient with Hodgkin Lymphoma in a 22 °C environment for 7 days. Again with a PET scan, they were able to observe BAT activation in the patient. This time, they did the opposite, seeing that BAT activation was less in the same patient who was left in a 28°C environment for 4 days.

In a new study on C. difficile, known as an infectious diarrheal bacterium, Drewes et al. found that this bacterium may be associated with colon cancer.

Bacteria such as B. fragilis and E. coli were already known to be associated with colorectal cancer. In this study, published in Cancer Discovery, it was determined that chronic C. difficile infection causes changes in colon progenitor cells. This change has been observed to have the potential to induce colonic carcinogenesis.



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