Stem Cell Discovery for Cartilage Regeneration

[yorkere]

Here's a VERY interesting development (From my standpoint, since I suffer from such severe osteoarthritis of the shoulders that I'm due for shoulder arthroplasty this coming June):

Stem cells offer cartilage repair hope for arthritis sufferers

Research being presented today (11 April) at the UK National Stem Cell Network Annual Science Meeting in Edinburgh could offer hope that bone stem cells may be harnessed to repair the damaged cartilage that is one of the main symptoms of osteoarthritis.

Scientists at Cardiff University have successfully identified stem cells within articular cartilage of adults, which although it cannot become any cell in the body like full stem cells, has the ability to derive into chondrocytes - the cells that make up the body?s cartilage ? in high enough numbers to make treatment a realistic possibility. The team have even been able to identify the cells in people over 75 years of age.

Osteoarthritis affects over 2M people in the UK and occurs when changes in the make up of the body?s cartilage causes joints to fail to work properly. At its worse it can cause the break up of cartilage, causing the ends of the bones in the joint to rub against each other. This results in severe pain and deformation of the joint. One current treatment to treat damaged cartilage due to trauma in younger patients is to harvest cartilage cells from neighbouring healthy cartilage and transplant them into the damaged area. Unfortunately, only a limited number of cells can be generated.

The research team, funded by the Arthritis Research Campaign and the Swiss AO Foundation, have identified a progenitor, or a partially derived stem cell in bovine cartilage that can be turned into a chondrocyte in culture. Their breakthrough came in identifying a similar cell in human cartilage that was more like a stem cell with characteristics that they could be used to treat cartilage lesions due to trauma but also mark the onset of osteoarthritis

Lead researcher Professor Charlie Archer from the Cardiff School of Biosciences said: ?We have identified a cell which when grown in the lab can produce enough of a person?s own cartilage that it could be effectively transplanted. There are limitations in trying to transplant a patient?s existing cartilage cells but by culturing it from a resident stem cell we believe we can overcome this limitation.

?This research could have real benefits for arthritis sufferers and especially younger active patients with cartilage lesions that can progress to whole scale osteoarthritis.?

Prof Archer commented: ?We have embarked on the next stage which is to conduct and animal trial which is a necessary pre-requisite to a clinical trial which we hope to start next year if the results are positive?

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Contact

Professor Charlie Archer, Cardiff University
Tel: 029 208 75206, email: archer@cardiff.ac.uk

 

[Henry Young]

Precursor to cartilage cells

There are three major types of cartilage in the body: hyaline cartilage, elastic cartilge, and fibrocartilage. Hyaline cartilage and elastic cartilage have a supportive tissue around them called a perichondrium. The perichondrium is actually a two-layered structure. The inner layer is composed of lineage-committed progenitor cells called chondroblasts, while the outer larer is composed of fibroblasts (lineage-committed cells that will form connective tissue). The chondroblasts will actually repair damaged cartilage by adding to the existing cartilage by a process called appositional (from the outside) growth. Unfortunately, it usually takes about two years of non-use for this process to occur (something most people do not have the patience for). Also, within the cartilage itself, new cartilage cells are formed by the division of existing chondrocytes (differentiated cartilage cells). This division occurs in structures called cell nests (isogenous groups). This method of repair is by a process called interstitial (in-between) growth. The reason cartilage takes so long to repair itself, in contrast to bone, is that it does not have its own blood supply. Rather it has to rely on nutrients diffusing through the cartilage matrix to keep the cells healthy and repaired.

The researchers are probably using chondroblasts from the inner layer of the perichondrium to effect the repair process. One of the down sides of using progenitor cells is that they have a defined biological lifespan (which begins at birth) of approximately 70 population doublings (called Hayflick's limit). If one makes the cells proliferate faster than normal, they reach Hayflick's limit faster than normal. All differentiated cells in our bodies are preprogrammed to senesce and die when they reach Hayflick's limit.

One of the hallmarks of stem cells, on the other hand, is their apparent ability for unlimited cell divisions. The reason for this is because they have not committed themselves to a particular tissue lineage. Once commitment occurs, their biological clock starts, and they have a lifespan of 70 populations before they senesce and die.

Articular cartilage, which lines the surfaces of your (articulating) bones is a special form of hyaline cartilage. Take care, Dr. Young

 

[yorkere]

Thank You!

Dr. Young:

Many thanks for posting your comments; they've clarified things quite a bit...I've had to delay my shoulder arthroplasty 'till sometime next year, primarily because I could not make reliable arrangements to be taken care of AFTER the surgery. Turns out that my Medicare Part A would NOT cover me for rehabilitation in a "Skilled Nursing Facility" (SNF)!! Apparently the policy is if I still had one arm reasonably functional, and can walk, then I'm on my own afterward!! The cost of staying somewhere suitable ranges between $700/week to $1100/week, so I've got to try to financially prepare for bearing these costs myself....Incidently, below are a few interesting items regarding stem cell therapy used for joint regeneration:

Biology of the Cell (2005) 97, (289?301) (Printed in Great Britain)
Review article
Stem-cell-driven regeneration of synovial joints
Jeremy J. Mao1

Tissue Engineering Laboratory, Departments of Anatomy and Cell Biology, Bioengineering, and Orthodontics, University of Illinois at Chicago, Chicago, 801 South Paulina Street, Illinois 60612, U.S.A.

And :

J Bone Joint Surg Am. 2005 May;87(5):936-44.

Tissue-engineered osteochondral constructs in the shape of an articular condyle.

Alhadlaq A, Mao JJ.

Department of Anatomy, Tissue Engineering Laboratory, MC 841, University of Illinois at Chicago, 801 South Paulina Street, Chicago, Illinois 60612, USA.

I haven't included the abstracts for the above for the sake of brevity...the information that can be found seems to indicate that a lot of very hard and effective work is underway at a very rapid pace; maybe if I delay long enough, I won't have to go through actual surgery at all!