奇妙的骨髓：即使只是走路，运动也会如何生长新的骨骼和

StephenW

Marvellous marrow: How exercise, even if it’s just walking, grows new bone and immune cells
Scientists have discovered bone-making cells lining the blood vessels in bone marrow. They keep us healthy. Photo: Getty
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Scientists have identified a another way that exercise strengthens bones and immune function. And they also found how we get sick if we neglect our bone health.

For a long time it was held that mechanical pressure from walking, running or lifting weights stimulated bones to produce new bone cells and lymphocytes – the B and T cells that work to fight infections.

The hard bone was believed to absorb all the shock from exercise or other movement, insulating the marrow inside bones.
This was wrong

Scientists at the Children’s Medical Center Research Institute (CRI) in Dallas, Texas, have identified a specialised environment, known as a “niche”, in bone marrow – and it’s in this niche where the new bone and immune cells are produced.

The study also found that “movement-induced stimulation is required for the maintenance of this niche, as well as the bone and immune-forming cells that it contains”.

In other words, it is movement that keeps not only our bones strong, but helps our illness-fighting capability.
In other words, use it or lose it

According to a statement from the CRI:

    The researchers discovered that forces created from walking or running are transmitted from bone surfaces along arteriolar blood vessels into the marrow inside bones.
    These blood vessels, known as arterioles, are small arteries that feed blood into capillary beds.
    Bone-forming cells that line the outside of these blood vessels sense these forces and are induced to proliferate.
    This allows the formation of new bone cells, which helps to thicken bones. But the bone-forming cells also secrete a growth factor that increases the frequency of cells that form lymphocytes around the arterioles.

Researchers have discovered a niche in the bone marrow where new bone and immunity cells are made from the mechanical pressure of exercise. Photo: UT Southwestern
And this is where the mice come in

The scientists tinkered with this process in mice by “switching off the ability of the bone-forming cells to sense pressure caused by movement.”

The result? It reduced the formation of new bone cells and lymphocytes, causing the mouse bones to become thinner, and reduced the ability of the mice to clear bacterial infections.

“As we age, the environment in our bone marrow changes and the cells responsible for maintaining skeletal bone mass and immune function become depleted,” said Dr Sean Morrison, director of CRI, in a prepared statement.
But can exercise reverse the cell-dying effects of ageing?

Dr Morrison said “very little” was known about how this environment changes (the niche in the bone marrow) or why these cells decrease with age.

To see if bone-loss could be reversed, Dr Bo Shen, a postdoctoral fellow in Morrison’s laboratory, gave the mice running wheels for exercise. Mice love to run.

He found the bones of these mice became stronger with exercise, while the number of bone-making cells and lymphocyte progenitors around the arterioles increased.

See here for advice from the Mayo Clinic on bone health.

StephenW

奇妙的骨髓：即使只是走路，运动也会如何生长新的骨骼和免疫细胞
科学家发现了在骨髓血管内衬的造骨细胞。它们使我们保持健康。照片：盖蒂
约翰·埃尔德约翰·埃尔德
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科学家们发现了锻炼身体以增强骨骼和免疫功能的另一种方法。他们还发现，如果我们忽视骨骼健康，就会生病。

长期以来，人们一直认为，走路，跑步或举重产生的机械压力会刺激骨骼产生新的骨骼细胞和淋巴细胞，即抵抗感染的B细胞和T细胞。

人们认为，坚硬的骨头可以吸收运动或其他运动产生的所有震动，从而使骨头内部的骨髓绝缘。
这是错的

德克萨斯州达拉斯市儿童医学中心研究所（CRI）的科学家们已经在骨髓中发现了一种特殊的环境，称为“小生境”，正是在这个小生境中产生了新的骨骼和免疫细胞。

这项研究还发现，“运动诱导的刺激是维持这种生态位及其所包含的骨骼和免疫形成细胞所必需的”。

换句话说，运动不仅使我们的骨骼保持强壮，而且还增强了我们的抗病能力。
换句话说，使用它或失去它

根据CRI的声明：

    研究人员发现，步行或跑步产生的力从骨骼表面沿着小动脉血管传递到骨骼内的骨髓中。
    这些血管称为小动脉，是将血液供入毛细血管床的小动脉。
    衬在这些血管外部的成骨细胞会感觉到这些力，并被诱导增殖。
    这样可以形成新的骨细胞，从而有助于增厚骨骼。但是，骨形成细胞还分泌一种生长因子，该因子增加了在小动脉周围形成淋巴细胞的细胞的频率。

研究人员已经在骨髓中发现了一个利基，其中的机械压力可以制造出新的骨骼和免疫细胞。照片：UT Southwestern
这是老鼠进来的地方

科学家通过“关闭骨形成细胞感知运动引起的压力的能力”，在老鼠中进行了修补。

结果？它减少了新骨细胞和淋巴细胞的形成，导致小鼠骨骼变薄，并降低了小鼠清除细菌感染的能力。

CRI主任肖恩·莫里森（Sean Morrison）博士在一份准备好的声明中说：“随着年龄的增长，骨髓的环境发生变化，负责维持骨骼质量和免疫功能的细胞被消耗掉。”
但是，运动可以逆转衰老对细胞造成的影响吗？

莫里森博士说，关于这种环境如何变化（骨髓中的小生境）或这些细胞为何随年龄而减少的了解很少。

为了研究骨骼损失是否可以逆转，莫里森实验室的博士后研究员沉博士给老鼠跑了滚轮进行锻炼。老鼠喜欢跑步。

他发现这些老鼠的骨骼随着运动变得更强壮，而小动脉周围的造骨细胞和淋巴细胞祖细胞的数量却增加了。

请参阅此处，以获得梅奥诊所关于骨骼健康的建议。