2 replies to this topic

[ta5]

I noticed how bones seemed to be surprising important for longevity. There's the statistic that 50% of patients with a hip fracture die within 6 months. I always wondered why that would be. They could just be associated with general aging as a common cause. But, then we also have the data showing bisphosphonates extend life. The study below suggests a relationship between bones, insulin, muscle, and longevity, and points out that bones produce stem cells. The link below is to the full text.

 

Aging (Albany NY). 2021 Mar 19;13. doi: 10.18632/aging.202727.

Whole-life body composition trajectory and longevity: role of insulin

Yu-Hsuan Lin, Shiow-Chwen Tsai, Sheng-Ju Chuang, M Brennan Harris , et al.

The present study assessed the body composition trajectory of rats (N = 96) placed into 5 groups according to lifespan, using dual-energy x-ray absorptiometry every 6 months until end-of-life. A striking linearity between lifespan and bone mass percentage (not absolute bone mass) was observed. Long-lived rats show a higher bone mass percentage with a delayed insulin rise to a similar peak level as short-lived counterparts, followed by insulin declines and bone mass loss. Decreasing insulin after streptozotocin (STZ) injection caused a rapid bone mass loss (-10.5%) with a decreased 5-day survival rate to 35% in old rats (20 months). Insulin replacement to STZ-injected rats completely blocked bone mass loss and increased the survival rate to 71%. Normal old rats (20 months) had faster lean mass loss despite greater myofiber regeneration (centronucleation) compared with the young rats (4 months). Increased CD68+ and CD163+ cell infiltration into insulin-depleted muscle suggests a bone marrow cell exhaustion by aging muscle. Bone produces stem cells and phagocytes to continuously rejuvenate peripheral tissues. Our data suggests that aging and unsustainable life is associated with development of disproportionality between bone and the growing body size, partly due to insulin reversal from hyperinsulinemia during late life.

PMID: 33744845

[sub7]

ta5,

 

This is very significant. Many posters here, especially QuestforLife, have repeatedly drawn our attention to the importance of bones for the extension of maximum lifespan.

 

The first link you posted " bisphosphonates extend life" is 10 years old. So very frustrating that there is no follow up on that really (there is very little bit)

 

In the above text, this part is crazy important
" bone marrow cell exhaustion by aging muscle.
Bone produces stem cells and phagocytes to continuously rejuvenate peripheral tissues."

 

What is your interpretation? Where can we obtain the greatest bang for the buck? Should we focus on bone marrow cells renewing themselves, so they can
continue supporting aging muscle without exhausting themselves in the process?
Or should we focus on muscle so that it can remain young by way of local / niche resources (local stem cells?) and does not need to depend on bone marrow as heavily.

[Danail Bulgaria]

"There's the statistic that 50% of patients with a hip fracture die within 6 months. I always wondered why that would be."

They lay down for a long period and their health detoriates extremely fast. Thats why they die. Especially if they are elder. This is known for a long time in the medicine.

 

"the data showing bisphosphonates extend life."

It is an anticancer drug. It is logical to extend at some small extent the life of those elders in the study, who had an undiagnosed cancer.

 

"Long-lived rats show a higher bone mass percentage with a delayed insulin rise to a similar peak level as short-lived counterparts"

The higher bone mass may mean that they have been healthier during thir life. delayed insulin rise means they had no diabetes. These both in combination are enough to explain the longer life without a molecular mechanism to be involved.