Exercise can cause cells deep in our bones to restore and strengthen our immunity suggests new research. It is a process that takes the meaning of ‘bone rattling’ to a whole new level.
We already know that exercise can improve almost every aspect of health: sleep, mental health and the risk of disease.
However, studies increase the importance of exercise as people get older. New research published in Nature contributes to the stack, finding movement stimulates bone regeneration and strengthens the immune system in previously unknown ways.
The study, which involved placing older mice on exercise wheels and evaluating their bone density and composition among other tests, revealed a specialized area in bone marrow that generates the precursors to bone cells and immune responses.
This ‘niche’ usually decreases with age. However, the study team observed that stimulation coupled with exercise, such as exercise with a large impact, increases the health-enhancing activity.
If the idea that cells respond to movement sounds new – or even strange – it is because it is.
“Our study raises the possibility that there may be much more dependent on mechanical stimulation than we thought,” says senior author Sean Morrison, director of the Children’s Medical Center Research Institute at UT Southwestern. Reverse.
“We know exercise is really good for you, but we get a fuller picture of why it’s good for you.”
LONELINESS is a regular series of Reverse about the scientific strategies to live better, healthier and longer without medicine. Get more in us Hacks Index.
How it affects longevity – It is known that bones weaken as we age. Specialized cells in bone marrow, including osteolectin cells and lymphoid progenitors, also weaken over time.
Immune systems get hit again because older bone marrow produces less lymphocytes – also known as the T- and B-cells that fight disease.
It has been established that certain types of exercise stimulate legs in a way that leads to bone formation – usually activities with a big impact such as jumping, running or climbing. This study takes the knowledge to the next level.
“The essential advancement in this study is to identify a new way in which exercise strengthens our bones and immune function,” says Morrison.
It also provides a more precise way to understand the ways in which aging bones and immune systems can weaken over time, Morrison explains. The team noted that mice running on a wheel experienced an expansion of the bone and the immune cell boosting of a niche in the marrow of bearing bones, as well as increased bone thickness and density.
In addition, researchers have discovered that a subset of stem cells that could become the precursors of bone cells, known as osteocytes, can be identified by their ability to produce a growth factor, osteolectin.
This growth factor, in turn, is involved in the induction of immune cells. When osteolectin was affected, the ability of the mice was also to fight bacterial infection.
The study also revealed that a repressive receptor (called PIEZO1) within the osteolectin cells depleted the specialized cell area in response to mechanical force. This reinforces the idea that exercise – especially exercise that strikes bones physically – is crucial for the maintenance of the cells that keep our bones and our immune system strong.
These results also bring us one step closer to understanding why and how exercise helps counteract the effects of osteoporosis, for example a common aging disease, especially in women.
Why is this a hack? Although this study looked at the bone marrow of mice and how the cells respond to it, it is likely that the findings of the study have implications for human life.
“We can not say for sure,” Morrison said. “But there is a remarkable resemblance between the blood-forming system in mice and the blood-forming system in humans.”
The study is related to what we may already see in human life – but may not fully understand.
“When astronauts enter space, and their legs are unloaded, their legs become thinner and their immune system drops,” Morrison explains. “So these observations are very similar to what we know happens to humans.”
And although researchers understand that mechanical force can stimulate bone cells closer to the meeting between bone and marrow, ‘humans have not had a way of explaining how the mechanical forces would really penetrate into the bone marrow’, he says.
Next time you climb a set of stairs, you can think of the movement of your feet that stretches deep into the smallest blood vessels in your legs, which has stimulated the creation of important new cells.
Hack score from 10 – ☠️☠️☠️☠️ (4/10)
Summary: Stromal cells in adult bone marrow expressing leptin receptor (LEPR) are a critical source of growth factors, including stem cell factor (SCF), for the maintenance of hematopoietic stem cells and early restricted progenitors. LEPR+ cells are heterogeneous, including skeletal stem cells and osteogenic and adipogenic progenitors, although few markers were available to distinguish this subset or compare their functions. Here it is shown that the expression of an osteogenic growth factor, osteolectin, distinguishes the peri-arteriole LEPR+ cells ready to undergo osteogenesis of peri-sinusoidal LEPR+ cells ready to undergo adipogenesis (but retaining osteogenic potential). Peri-arteriolar LEPR+osteolectin+ cells are rapidly dividing, transient osteogenic progenitors that increase in number after rupture and become depleted during aging. Deletion of Scf of osteolectin in adults+ cells had no effect on the maintenance of hematopoietic stem cells or most restricted progenitors, but depleted common lymphoid progenitors, impairing lymphopoiesis, bacterial clearance, and survival after acute bacterial infection. Peri-arteriolar osteolectomy+ cell maintenance requires mechanical stimulation. Voluntary running increased, while the download of the hind leg decreased, the frequencies of peri-arteriolar osteolectin+ cells and common lymphoid progenitors. Deletion of the mechanosensitive ion channel PIEZO1 from osteolectin+ cells that have depleted osteolectin+ cells and common lymphoid progenitors. These results show that a peri-arteriolar niche for osteogenesis and lymph nodes in bone marrow is maintained by mechanical stimulation and depleted during aging.