AsianScientist (Feb. 18, 2019) – Vitamin D may aggravate a bone marrow disease known as myelofibrosis, say researchers at Kobe University, Japan. They published their findings in the journal Blood.
There are three types of blood cells in the human body—white blood cells, red blood cells and platelets. All three types are created from hematopoietic stem cells located in the bone marrow.
Myelofibrosis is characterized by an abnormal increase in fibroblasts, cells that produce collagen fibers. The bone marrow becomes filled with these fibers, preventing the normal production of blood cells. As a result, patients suffer from symptoms such as bone hardening (osteosclerosis).
Although vitamin D is often associated with positive effects on bone, researchers led by Dr. Kanako Wakahashi and Associate Professor Yoshio Katayama of Kobe University found that hematopoietic stem cells were strongly stimulated by vitamin D signaling and grew into immune system cells called macrophages. These pathological macrophages stimulated young osteoblasts (cells that create bone) to induce myelofibrosis and bone hardening.
The researchers showed that the accumulation of pathological macrophages was reduced when mice were fed on a low vitamin D diet, and this prevented the onset of myelofibrosis. Furthermore, in a separate mouse model (JAK2V61F transgenic mice) that presents similar symptoms to myelofibrosis patients, the researchers were able to prevent bone marrow fibrosis by keeping mice on a low vitamin D diet, blocking vitamin D receptor signals and suppressing macrophages.
“The only permanent cure for this disease is hematopoietic stem cell transplant, but this method is unsuitable for many elderly patients. These new findings may help in the development of a treatment method for the elderly via targeting the vitamin D pathway and macrophages,” said Katayama.
The article can be found at: Wakahashi et al. (2019) Vitamin D Receptor-mediated Skewed Differentiation of Macrophages Initiates Myelofibrosis and Subsequent Osteosclerosis.
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Source: Kobe University; Photo: Shutterstock.
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