Our Bones Aren’t Just a Framework; They’re Cell-Producing Machines

by Chris Centeno, MD /

Receive a Regenexx® Patient Info Packet by email and learn why it's a superior regenerative solution.

You have many stem cell types in your body, and today I’d like you to learn about one that lives in your bone marrow and why it lives there and not somewhere else. We’ll do that through a discussion of fish and frogs. Meet the HSC.

What Are Hematopoietic Stem Cells?

You might not realize that our bones aren’t simply a scaffolding that serves as the body’s supporting framework, they are also one of the human body’s blood cell-producing machines. Hematopoietic stem cells (HSCs) are the cells from which all blood cells (e.g., erythrocytes, lymphocytes, megakaryocytes, neutrophils, macrophages, etc.) are formed. Our circulating blood cells live hard and die fast, which means they must continuously be replaced. This assembly line of blood cell production occurs in humans in the bone marrow inside our bones, with those hematopoietic stem cells producing in excess of hundreds of billions of new blood cells daily, a process known as hematopoiesis (hemato- meaning “blood” and -poiesis meaning “producing” or “forming”).

Today, we’re going to focus on hematopoietic stem cells (HSCs), but it’s also important to differentiate these from mesenchymal stem cells (MSCs), which are also primarily found in the bone marrow. MSCs, however, produce cells that form musculoskeletal tissue, such as bone (osteocytes), muscle (myocytes), and cartilage (chondrocytes) cells. However, HSCs can help repair muscle as they can replace muscle stem cells in time of need.

Interestingly, locations for HSC sources in non-mammals vary, often occurring in organs, such as the kidneys. Let’s explore.

HSC Location Attributed to Ultraviolet Light Protection

Researchers in the new study, using humans as the mammal observation and zebrafish as the non-mammal observation, investigated the zebrafish to determine why HSCs are sourced in the kidneys. The answer was found in melanocytes. In humans, melanocytes are cells that produce a pigment called melanin, which determines the color of our skin, hair, eyes, and so on. In other species, such as fish, snakes, and birds, melanocytes also exist and provide the coloring for scales, feathers, and so on. Researchers determined that a specific pattern of the melanocytes on the zebrafish actually shaded the kidneys, protecting them from ultraviolet light.

Researchers also tested the effect of UV light specifically on the HSCs in the kidneys of the fish (literally by turning the fish upside down in one test and exposing the unshaded underside of the kidney to UV light) and determined that the UV light damages the DNA of the cells. Therefore, the specific coloring design, the “melanocyte umbrella,” over the kidneys of the zebrafish protects the HSCs from damage, making the kidneys an ideal location in this species for HSCs.

Another fascinating facet to the study—researchers also studied the effect of UV light in terrestrial frogs. As tadpoles, HSCs were sourced in the kidneys, which also had the same melanocyte protection described in the zebrafish above. However, as the tadpoles grew legs and transitioned to land-dwelling frogs, the HSCs also transitioned from the kidneys to the bone marrow. This, again, was attributed to the HSC protection that would be necessary from UV light.

The study pointed out that in mammals, an organ, such as the kidney, would not be capable of insulating the HSCs from UV light; however, the bone marrow, well protected by the dense bones, provides the perfect light-free environment for HSCs to thrive and maintain their stringent blood cell-producing schedule.

Problems That Can Occur with Hematopoietic Stem Cells

UV light exposure or not, our HSCs can still become permanently damaged, either due to genetics (inherited mutations) or due to environmental factors (somatic mutations), such as smoking or chemical exposure. These mutations can be passed to replicated cells and can even lead to cancer and other diseases, though our immune cells do a pretty good job of destroying these bad cells. The risk of these somatic mutations, however, does increase with age, and when they occur in our HSCs, our risk of heart disease, stroke, hematologic cancers, and other diseases increases.

The upshot? Understanding the different stem cell types found in your bone marrow is important. In addition, turns out that there’s a reason that these critical repair cells live deep inside thick bone. They’re there to protect themselves and you from the harmful effects of UV and other types of radiation that may mutate these cells. So hopefully you’ll look at your bones a little differently now, as both structure and the key to a long and active life.

Category: Latest News

Leave a Reply

Your email address will not be published. Required fields are marked *

6 thoughts on “Our Bones Aren’t Just a Framework; They’re Cell-Producing Machines

  1. Mita

    Hi
    I had total knee replacement 10 yers ago.
    After few months started getting rashes and very itchy. After 2 years I found out I was allergic to the component in my body nickle and cobalt.
    After so many years can I redo my knee surgery.
    Please help.

    1. Regenexx Team

      Mita,
      You’d need to speak to your surgeon about whether that is possible in your case. Allergies to, and metal toxicity from, are significant issues in joint replacement. Please see: https://regenexx.com/blog/knee-replacement-questions/

  2. Carolyn Stoops

    I knew little about various Stem Cell Injections – but do know that mine came from a “Placenta” injection of 1 cc into my left ankle on 3/31/2018 from a licensed orthopedic doctor. It’s been 2 months now and at first there was a lot of swelling and stiffness. Swelling has gone down on my foot, but the ankle is swollen and stiff. I was just wondering if it’s a time element that is causing the swelling and I need to be patient? Orthopedic doctors here do not have any real knowledge on this new medical advances in stem cell. I was hoping to gather more information on your website. My age is an active 78, so that alone could be the reason why it’s taking so long to get back to regenerate. Any thoughts and comments would really be appreciated. Thank you. Carolyn Stoops

    1. Regenexx Team

      Carolyn,
      I am so sorry to tell you that Placenta injections do not contain live or viable stem cells. Unfortunately, because we don’t know the contents of the injection, we don’t know why your still experiencing swelling 3 1/2 months later. Please do check with the Doctor who did the injection. Please see: https://regenexx.com/blog/many-times-can-violate-fdca-one-marketing-email/

  3. kathy

    Does the mineral Strontium Citrate have any effect on stem cells? I am reading the use of this for treatment of osteoporosis?

    1. Regenexx Team

      Kathy,
      Curcumin has been found to be very good for bone health. Please see: https://regenexx.com/blog/curcumin-for-bone-health/
      This study looked at stronium citrate in combination with some other supplements: https://www.ncbi.nlm.nih.gov/pubmed/28130552

Chris Centeno, MD

Regenexx Founder

Chris Centeno, MD is a specialist in regenerative medicine and the new field of Interventional Orthopedics. Centeno pioneered orthopedic stem cell procedures in 2005 and is responsible for a large amount of the published research on stem cell use for orthopedic applications.
View Profile

Get Blog Updates by Email

Get fresh updates and insights from Regenexx delivered straight to your inbox.

Regenerative procedures are commonly used to treat musculoskelatal trauma, overuse injuries, and degenerative issues, including failed surgeries.
Select Your Problem Area
Shoulder

Shoulder

Many Shoulder and Rotator Cuff injuries are good candidates for regenerative treatments. Before considering shoulder arthroscopy or shoulder replacement, consider an evaluation of your condition with a regenerative treatment specialist.

  • Rotator Cuff Tears and Tendinitis
  • Shoulder Instability
  • SLAP Tear / Labral Tears
  • Shoulder Arthritis
  • Other Degenerative Conditions & Overuse Injuries
Learn More
Cervical Spine

Spine

Many spine injuries and degenerative conditions are good candidates for regenerative treatments and there are a number of studies showing promising results in treating a wide range of spine problems. Spine surgery should be a last resort for anyone, due to the cascade of negative effects it can have on the areas surrounding the surgery. And epidural steroid injections are problematic due to their long-term negative impact on bone density.

  • Herniated, Bulging, Protruding Discs
  • Degenerative Disc Disease
  • SI Joint Syndrome
  • Sciatica
  • Pinched Nerves and General Back Pain
  • And more
Learn More
Knee

Knees

Knees are the target of many common sports injuries. Sadly, they are also the target of a number of surgeries that research has frequently shown to be ineffective or minimally effective. Knee arthritis can also be a common cause for aging athletes to abandon the sports and activities they love. Regenerative procedures can be used to treat a wide range of knee injuries and conditions. They can even be used to reduce pain and delay knee replacement for more severe arthritis.

  • Knee Meniscus Tears
  • Knee ACL Tears
  • Knee Instability
  • Knee Osteoarthritis
  • Other Knee Ligaments / Tendons & Overuse Injuries
  • And more
Learn More
Lower Spine

Spine

Many spine injuries and degenerative conditions are good candidates for regenerative treatments and there are a number of studies showing promising results in treating a wide range of spine problems. Spine surgery should be a last resort for anyone, due to the cascade of negative effects it can have on the areas surrounding the surgery. And epidural steroid injections are problematic due to their long-term negative impact on bone density.

  • Herniated, Bulging, Protruding Discs
  • Degenerative Disc Disease
  • SI Joint Syndrome
  • Sciatica
  • Pinched Nerves and General Back Pain
  • And more
Learn More
Hand & Wrist

Hand & Wrist

Hand and wrist injuries and arthritis, carpal tunnel syndrome, and conditions relating to overuse of the thumb, are good candidates for regenerative treatments. Before considering surgery, consider an evaluation of your condition with a regenerative treatment specialist.
  • Hand and Wrist Arthritis
  • Carpal Tunnel Syndrome
  • Trigger Finger
  • Thumb Arthritis (Basal Joint, CMC, Gamer’s Thumb, Texting Thumb)
  • Other conditions that cause pain
Learn More
Elbow

Elbow

Most injuries of the elbow’s tendons and ligaments, as well as arthritis, can be treated non-surgically with regenerative procedures.

  • Golfer’s elbow & Tennis elbow
  • Arthritis
  • Ulnar collateral ligament wear (common in baseball pitchers)
  • And more
Learn More
Hip

Hip

Hip injuries and degenerative conditions become more common with age. Do to the nature of the joint, it’s not quite as easy to injure as a knee, but it can take a beating and pain often develops over time. Whether a hip condition is acute or degenerative, regenerative procedures can help reduce pain and may help heal injured tissue, without the complications of invasive surgical hip procedures.

  • Labral Tear
  • Hip Arthritis
  • Hip Bursitis
  • Hip Sprain, Tendonitis or Inflammation
  • Hip Instability
Learn More
Foot & Ankle

Foot & Ankle

Foot and ankle injuries are common in athletes. These injuries can often benefit from non-surgical regenerative treatments. Before considering surgery, consider an evaluation of your condition with a regenerative treatment specialist.
  • Ankle Arthritis
  • Plantar fasciitis
  • Ligament sprains or tears
  • Other conditions that cause pain
Learn More

Is Regenexx Right For You?

Request a free Regenexx Info Packet

REGENEXX WEBINARS

Learn about the #1 Stem Cell & Platelet Procedures for treating arthritis, common joint injuries & spine pain.

Join a Webinar

RECEIVE BLOG ARTICLES BY EMAIL

Get fresh updates and insights from Regenexx delivered straight to your inbox.

Subscribe to the Blog

FOLLOW US

Copyright © Regenexx 2019. All rights reserved. | Privacy Policy

*DISCLAIMER: Like all medical procedures, Regenexx® Procedures have a success and failure rate. Patient reviews and testimonials on this site should not be interpreted as a statement on the effectiveness of our treatments for anyone else.

Providers listed on the Regenexx website are for informational purposes only and are not a recommendation from Regenexx for a specific provider or a guarantee of the outcome of any treatment you receive.