I was informed by this post in LimbLengtheningForum.com that VICE themselves have started to look into the biotech revolution that is going on. I talked about CRISPR-Cas9 extensively already, but VICE has also started to report on it, like all of the other major news sites.

Apparently a rep from VICE, a Isobel Yeung interviewed the people who had their babies gender determined by The Fertility Institute with Dr. Steinberg. The Process is called Preimplantation Genetic Diagnosis (PGD). It is similar to the older methods where lab technicians will look through the millions of sperms that the male partner has donated and choose the most strong, alive sperm to inject into the female egg.

I personally was not able to get a copy of this HBO VICE episode but apparently some rep of the Fertility Institute did say that you can ask to have children that are tall. Now in 2016, it is already possible for potential future parents to ask the doctors to specifically select for a eye color.

Given what I know about humans, the parents will probably ask for either green or blue eyes, since those colors are unique. So this couple, Deborah and Jonathan got to choose their babies gender (girl) and eye color. If they were given the option to choose for height, they definitely would have. It seems that the VICE rep Isobel was absolutely hooked on the idea that you can make 99.97% sure that you can have your kids to turn out much taller than they would have if you just let nature and randomness talk is course.

The time frame for that ability to choose height in their designer babies: 5 years. That’s it, as predicted by Dr. Steinberg.

Personally I am not sure how the gene editing technicians can get the height thing down. The only gene that has been definitively discovered which has any effect on height is the HMGA2 gene, which required that you have two of these gene alleles.

In one of the pictures, Isobel is pictured with CTO Cunxiang Ju at the National Resource Center for Mutant Mice in Nanjing, China, where they use CRISPR technology to edit the genes of mice. This was all from the DailyMail UK article available here.

From the article…

….”Isobel noted that the process is fairly inexpensive, costing only about $150 for the CRISPR Cas-9m protein, which uses molecular blades to make cuts in host DNA, and getting a syringe. 

As part of its 2011 plan, China has devoted more than $350 billion to biotechnology. At the National Research Center for Mutant Mice in Nanjing, China, CRISPR technology is now being used to edit the genes of mice in an effort to isolate desired traits, and the facility can hold up to 450,000 mice. 

Isobel said that the lab is testing mice for everything from the jet lag gene, which regulates sleep and wake rhythms, to obesity and diabetes. The correspondent noted that there is even a ‘boy genius’ in China who is trying to find a gene to that correlates to intelligence. She added that the research has huge potential to cure diseases and help humans evolve.”…

Nations like China and Russia, which is basically run like the former Soviet Union are definitely going to push ahead to get people of certain traits. They are trying to make ultra-tall, ultra-smart humans. This sounds like sci-fi and it may lead to a dystopian type of society Gattaca style, but that is the way human progress moves, which is to unrelentlesslly push forward.

Is this a good thing? I can not question the ethics of this thing since no matter how the USA physicians debate and agree on a decision, these other countries will push forward. Humans have almost a perfect history of trying to break the rules of nature, to get our own way.

If it is true that within 5 years, parents will be able to make sure their children turns out tall, imagine what else can be done in 25 years. I am absolutely sure that in 25 years, designer babies will become a culturally accepted phenomena.

In some ways, it could be a good thing if we think in terms of 19th century pseudo-scientific eugenics philosophy. (I know, this sounds slightly racist.)

Here are the facts.

• Blonde color in hair is recessive and is slowly disappearing through normal pairing and breeding.
• In the USA alone, 70% of “blonde” hair females are not real, but come from a bottle/dye/stylist. This is due to waves of different groups of people pairing off who arrived in the USA, since the USA is a country of immigrants. It was well known in the early 20th century that Italian, Spanish, and South European men with dark/black hair and brown eyes loved women with “blonde” hair, and pair bonded with them. This is true still in the modern age, where there is enough anecdotal evidence that Middle Eastern men, South Asian men, and African American men all have a above average predilection for girls who have outer physical traits which are only available from ethnic groups in Northern Europe. This meant that 100 years later, the mixing of “white” people has resulted in this recessive hair color being extremely rare.
• Ginger hair are even more recessive and more rare.
• More than 80% of the world has brown eyes while is it is only in the Caucasian “race” that we have any type of eye color variation (hazel, green, blue, amber, etc.) This includes ethnic groups that extend into the middle east, and the central asian countries.
• It is almost an absolute certainty that at the rate which caucasians are pairing with non-caucasians, the traits like blonde or ginger hair and non-brown eye colors will disappear within a few generations.
• It was discovered that there is a genetic basis for the stereotype of Northern Europeans being tall, which is validated. Northern Europeans are traditionally taller than most other ethnic groups in the world (except for certain pockets of tribes), which means that for males of that group, females of other races/ethnic groups would have a natural desire to mate with them, looking for their height genes for their offspring.

If the entire world only had brown eyes and black hair, wouldn’t it be boring, from a taxonomic point-of-view?

Maybe this whole trend of allowing parents to choose their babies would allow for the recessive traits of already extremely unique human traits to come back, in greater concentration?

In the modern age, we preach that we should love diversity and be able to appreciate all the different colors and shapes that humans come in. However, because we are so accepting and loving of all the colors, by the act of miscegenation, we are in fact pushing the world towards a state of blandness, where there is no differences anymore, once everyone has mixed together and we all look the same again, in say 200 years time.

I am not suggesting that due to a few hundred years of imperial influence by europeans that every single parent in the coming decade will wish for their kids to have rare traits like ginger hair and green eyes, and european/caucasian features, even with Asian or African American parents. That would be odd. What I am suggesting is that the parents will definitely want to go with tall stature/above average height, and increased raw IQ points, to make sure that their kids get as much of an advantage as possible to other children.

Since tennis is a method of mechanical stimulation on the bone and growth plate.  We can extrapolate its effects to other forms of mechanical stimulation.

Asymptomatic elite young tennis players show lateral and ventral growth plate alterations of proximal humerus on MRI.

“The specific aim of the study was to investigate and compare epiphyseal length and extension in the proximal humerus, closure in the growth plate and bone marrow signal intensity related to the proximal humeral physis in the dominant arm and the non-dominant arm of the asymptomatic adolescent elite tennis player.
The study sample included 35 asymptomatic elite young tennis players (15 males and 20 females, mean age 17.4 years ± 2.7). Each player contributed with two shoulders to the MRI measurement. The non-dominant arm was used as a control.
Relative reliability between the radiologists was excellent (ICC 0.78-0.96). Statistically significant differences between dominant arm and non-dominant arm in epiphyseal length (mm) laterally (DA 27.3 vs NDA 26.7) were shown. Statistically significant differences were also found in epiphyseal extension (mm) laterally (DA 36.1 vs NDA 35.1) and ventrally (DA 36.2 vs NDA 34.8). No statistically significant differences were found between dominant arm and non-dominant arm in epiphyseal extension (mm) medially (DA 31.7 vs NDA 31.7) and dorsally (DA 22.6 vs NDA 22.1).
Significant findings assessing MRI measurements of the epiphyseal plate in the asymptomatic adolescent elite tennis player might reflect a development of consecutive alterations in the epiphyseal plate in the dominant arm.”

“The cartilage of the epiphyseal plate might be 2–5 times weaker than surrounding fibrous tissue; therefore, epiphyseal (growth) plates are very sensitive to their surrounding mechanical environment”

“The epiphyseal plate consists of the fibrous part, providing mechanical support and the cartilaginous and bony part, acting together in transforming cartilage cells into bone. The rounded end of a long bone, the epiphysis, is divided into two types: traction epiphysis, primarily subjected to tensile forces, and pressure epiphysis, primarily subjected to compressive forces. Closure of the growth plate of the proximal humerus in the pediatric population starts around 14 years of age, and the last area to close is the posterolateral region that closes at 17 years of age”

“The shear stress arising from high torques during the arm cocking throwing phase in overhead sports is large enough to lead to deformation of the weak proximal humeral epiphyseal cartilage”

The difference in growth plate dimensions is not so much important as is the difference in overall length as higher growth plate height and width can occur in cases of stunted growth.

Playing tennis didn’t appear to have an affect on keeping the growth plate open.

“External rotation force applied to the proximal humeral physis during the overhead motion peaks just before maximal shoulder external rotation”

Joint Distraction is similar to what I’m experimenting with via finger pulling.

Sustained clinical and structural benefit after joint distraction in the treatment of severe knee osteoarthritis.

“Knee joint distraction (KJD) provides clinical benefit and tissue structure modification at 1-year follow-up. The present study evaluates whether this benefit is preserved during the second year of follow-up.
Patients included in this study presented with end-stage knee OA and an indication for total knee replacement (TKR); they were less than 60 years old with a VAS pain ≥60 mm (n = 20). KJD was applied for 2 months (range 54-64 days) and clinical parameters assessed using the WOMAC questionnaire and VAS pain score. Changes in cartilage structure were measured using quantitative MRI, radiography, and biochemical analyses of collagen type II turnover (ELISA).
Average follow-up was 24 (range 23-25) months. Clinical improvement compared with baseline (BL) was observed at 2-year follow-up: WOMAC improved by 74% and VAS pain decreased by 61%  Cartilage thickness observed by MRI (2.35 mm (2.06-2.65) at BL) was significantly greater at 2-year follow-up (2.78 mm (2.50-3.09); P = 0.03). Radiographic minimum joint space width (JSW) (1.1 mm (0.5-1.7) at BL) was significantly increased at 2-year follow-up as well (1.7 mm (1.1-2.3); P = 0.03). The denuded area of subchondral bone visualized by MRI (22% (95%CI, 12.5-31.5) at BL) was significantly decreased at 2-year follow-up (8% (3.6-12.2)). The ratio of collagen type II synthesis over breakdown was increased at 2-year follow-up.
Clinical improvement by KJD treatment is sustained for at least 2 years. Cartilage repair is still present after 2 years (MRI) and the newly formed tissue continues to be mechanically resilient as shown by an increased JSW under weight-bearing conditions.”

Below is the knee distraction method and a description:

“The distraction method was applied. In short, an external fixation frame consisting of two monotubes with internal coil springs was placed, bridging the knee joint. Each monotube was fixed to two bone pins on each end and, in stages, distracted for 5 mm (confirmed by X-ray). After instructions about pin site care, daily exercise, and physical therapy, the patients were discharged from the hospital. Patients were allowed and encouraged to load the distracted joint with full weight-bearing capacity, supported with crutches. In case of superficial (skin) pin tract infections, treatment with oral antibiotics for 5–7 days was provided (Flucloxacillin). Every 2 weeks the patients returned to the hospital and the monotubes were temporarily removed. The knee was bent, for 3–4 h, in a continuous passive motion device, with pain at the pin sites determining the maximum degree of flexion; on average, 25° (15–80°) flexion and full extension was reached. The monotubes were replaced and sufficient distraction was confirmed by X-ray examination and adjusted if needed.”

I think that this method of distraction is something that can be mimicked by something done manually.

“newly formed cartilaginous tissue; it might be, in part, fibrocartilaginous tissue.”

This study Effects of non-surgical joint distraction in the treatment of severe knee osteoarthritis. has the analysis of non-surgical but I can’t get the full study.

The idea of joint distraction in this case is not to stimulate the articular cartilage but to stimulate longitudinal bone growth.  There is no practical evidence that this may be the case that I am aware.  It is based on the observation that developing individuals have less pronounced epiphysis’ and that therefore the epiphysis may be a constraining factor on growth.

The epiphysis may constrain growth in a number of ways for example the two epiphysis may be akin to “like” charges of a battery and repel each other inhibiting further growth.

This study here does not provide any evidence about what affect joint distraction will have on healthy adults but it does show that joint distraction does have physiological effects on bone, cartilage, and likely MSCs.  All ingredients for inducing longitudinal bone growth.

So I’ve been doing finger pulling for a few weeks.  I’ve gotten a small but significant amount of results.   I’ve been doing it only on the right pinky finger.  I don’t expect you to be able to see the results but I can much more easily compare my finger length than I could do in photos.  And I’d still need x-rays before people would be convinced.  But now that I see results I am going to do more finger pulling(while still doing LSJL) to see if I can keep getting more results or if I “plateau”.

If this works then doing the arms will be easy you just pull the joints away from each other by grabbing onto your hand.  Doing spine and legs will be harder as someone would have to hold your head and pull your head and someone will have to hold your legs and pull them.

Now why would this work and not something like the rack or holding dumbells to stretch your arms?  First, your muscles are resisting the weight.  Second, one part of the joint can be stretched while the other is compressed.

This is why it’ll be hard to do it any way other than manually as you have to make sure that the joint is uniformly stretched.

So since I am starting to notice some results I’m going to increase the duration of 15 minutes to as often as possible probably 30min-1 hr while still doing LSJL.  Then we’ll see if I get more obvious results.

According to one study A bioengineering study of cavitation in the metacarpophalangeal joint “the sudden appearance of this low pressure bubble caused the joint to separate at a rapid rate and that the crack was caused by the sudden opening of the joint surfaces producing vibrations in the joint tissue. “<-so cracking joints can contribute to joint separation, perhaps even spinal height.  If you look at figure 2 and the joint space, the joint space is a lot bigger post crack. ” fluid containing high quantities of gas cannot support low pressures without cavitation taking place.” ” the separation between the joint surfaces does not return to its pre-cracking condition for a period of 15 minutes. ” “Some joints never crack. This may be because the joint space is too great. ”  ” the joint separation increases at a high rate, allowing the net flow of fluid into the low pressure regions.”

Here’s the histology of the joint and how the ligaments are positioned

I talk more about chiropractic here.

Understanding how Synovial Joints are formed may help us understand how to influence them to reinitiate longitudinal bone growth.

Formation of synovial joints and articular cartilage.

“Chondrocytes differentiate from mesenchymal progenitors and produce templates(anlagen) for the developing bones. Chondrocyte differentiation is controlled by Sox transcription factors. Templates for the neighbour bones are subsequently separated by conversion of differentiated chondrocytes into non-chondrogenic cells and emergence of interzone in which joints cavitation occurs. A central role in initiating synovial joint formation plays Wnt-14/beta-catenin signalling pathway.  Moreover, bone morphogenetic proteins and growth and differentiation factors are expressed at the site of joint formation. Joint cavitation{cracking your joints though it’s not clear if that’s what is meant by this study} is associated with increased hyaluronic acid synthesis. Hyaluronic acid facilitates tissue separation and creation of a functional joint cavity{Hyaluronic acid may inhibit fusion?}. Articular cartilage represents part of cartilage anlage that is not replaced by bone through endochondral ossification.  Peri-joint mesenchymal cells take part in interzone formation and that these interzone cells subsequently differentiate into articular chondrocytes and synovial cells. Anlage chondrocytes have a transient character and disappear after cessation of growth plate function while articular chondrocytes have stable and permanent phenotype and function throughout life.”

“Cartilage templates of neighbour bones are separated through development of non-cartilaginous region known as the interzone. The interzone is essential for joint formation since its removal by microdissection led to joint ablation and fusion of bones”<-this is interesting because it means that the interzone is likely a necessary condition for synovial joints and perhaps insertion of the inerzone in other regions can have uniques.

“During interzone formation articular progenitor cell specification prompts the downregulation of the gene for the master chondrogenic transcription factor SOX-9”

“The repressive signals that prevent chondrogenic differentiation within interzone are likely to promote differentiation along a fibrous lineage”

Since Hyaluronic Acid and Heparan Sulfate play a role in cavitation they may help create room for neo-growth plate formation(See Figure 1).

“Once formed, interzone differentiate in 3 layers: 2 chondrogenic, perichondrium-like layers that cover the cartilaginous surfaces and 1 intermediate layer of loose, avascular mesenchyme that separates them and continues peripherally in a vascular mesenchyme, the so-called synovial mesenchyme. Within interzone, along planes destined to become the articular surfaces of synovial joints cavitation occurs”

Necrosis may play a role in preventing cells in the interzone that have chondrogenic potential.  Necrosis may be a way that the body blocks neo-growth plate formation.

“HA acid may be an important factor in joint cavitation.  Activity of uridine diphosphoglucose dehydrogenase, an enzyme necessary for synthesis of UDP glucuronate, a component for HA production was increased in a narrow band of cells at the presumptive joint line prior to cavitation.  Joint cavitation is dependent on the behaviour of fibroblastic cells and/or adjacent chondrocytes, rather than macrophages. Hyaluronan and hyaluronan synthases were present in the interzone before and at the time of cavitation”

” joint cavitation could be facilitated by a rise in local hyaluronan concentration in an area of tissue where cohesion is dependent on the interaction between cellular CD44 and extracellular hyaluronan “<-Since a kind of joint cavitation may be involved to create the region for a neo growth plate,  Hyaluronic acid may be helpful in this endeavor.

“The interaction between HA and CD44 can induce both cell adhesion and cell separation, depending on the concentration of HA surrounding a cell population via receptor saturation, with increasing HA concentrations leading to cell separation”<-However, mesenchymal consedation rather than separation is a precursor to growth plate formation.

Genesis and morphogenesis of limb synovial joints and articular cartilage.

“Limb synovial joints are intricate structures composed of articular cartilage, synovial membranes, ligaments and an articular capsule. Together, these tissues give each joint its unique shape, organization and biomechanical function. Articular cartilage itself is rather complex and organized in distinct zones, including the superficial zone that produces lubricants and contains stem/progenitor cells. For many years there has been great interest in deciphering the mechanisms by which the joints form and come to acquire such unique structural features and diversity. Decades ago, classic embryologists discovered that the first overt sign of joint formation at each prescribed limb site was the appearance of a dense and compact population of mesenchymal cells collectively called the interzone. Work carried out since then by several groups has provided evidence that the interzone cells actively participate in joint tissue formation over developmental time. This minireview provides a succinct but comprehensive description of the many important recent advances in this field of research. These include studies using various conditional reporter mice to genetically trace and track the origin, fate and possible function of joint progenitor cells; studies on the involvement and roles in signaling pathways and transcription factors in joint cell determination and functioning; and studies using advanced methods of gene expression analyses to uncover novel genetic determinants of joint formation and diversity. The overall advances are impressive, and the findings are not only of obvious interest and importance but also have major implications in the conception of future translational medicine tools to repair and regenerate defective, overused or aging joints.”

“The superficial zone contains elongated and flat-shaped cells oriented parallel to the articular surface, held together by a largely collagenous matrix, and producing lubricin, hyaluronate and other anti-adhesive macromolecules essential for frictionless joint movement”

“Articular chondrocytes in the middle zone are round in shape, are usually organized in small vertical rows, and produce and maintain important extracellular components – particularly collagen II and aggrecan that confer the tissue with its key biomechanical feature: resilience. The chondrocytes in the bottom zone tend to be larger in size, are also active in matrix production and maintenance, and face the critical tissue boundary – referred to as the tidemark- between articular cartilage and underlying subchondral bone”

“the cartilaginous skeleton forming in the early limb is continuous and uninterrupted, as exemplified by the Y-shaped anlagen corresponding to the stylopod element (humerus or femur), the two zeugopod elements (radius-ulna and tibia-fibula), and the autopod rays corresponding to the phalangeal elements”

” The interzone is composed of flat-shaped cells oriented perpendicularly to the limb’s main axis, tightly bound via gap junctions and requiring the hypoxia regulator Hif-1α function. Because the interzone cells emerge at sites previously occupied by chondrocytes, this led to the suggestion that the interzone cells originate from, and are the direct descendants of, de-differentiated chondrocytes”

“interzone cells are not transient, actively take part in joint tissue formation, and constitute a progenitor cell cohort endowed with joint-formation capacity.”

“Articular and growth plate chondrocytes derive from common mesenchymal precursors originally expressing Dcx which then bifurcate into articular and growth plate chondrocytes. The TGFβ type II receptor (Tgfbr2) is essential for joint formation”

Here’s info on Dcx:

Doublecortin may play a role in defining chondrocyte phenotype.

“Embryonic development of articular cartilage has not been well understood and the role of doublecortin (DCX) in determination of chondrocyte phenotype is unknown. Here, we use a DCX promoter-driven eGFP reporter mouse model to study the dynamic gene expression profiles in mouse embryonic handplates at E12.5 to E13.5 when the condensed mesenchymal cells differentiate into either endochondral chondrocytes or joint interzone cells. Illumina microarray analysis identified a variety of genes that were expressed differentially in the different regions of mouse handplate. The unique expression patterns of many genes were revealed. Cytl1 and 3110032G18RIK were highly expressed in the proximal region of E12.5 handplate and the carpal region of E13.5 handplate, whereas Olfr538, Kctd15, and Cited1 were highly expressed in the distal region of E12.5 and the metacarpal region of E13.5 handplates. There was an increasing gradient of Hrc expression in the proximal to distal direction in E13.5 handplate. Furthermore, when human DCX protein was expressed in human adipose stem cells, collagen II was decreased while aggrecan, matrilin 2, and GDF5 were increased during the 14-day pellet culture. These findings suggest that DCX may play a role in defining chondrocyte phenotype.”

“DCX is expressed in the mesenchymal cells in mouse embryonic limb buds, however, a population of mesenchymal cells maintain DCX expression when they differentiate into joint interzone cells and articular chondrocytes, whereas the other population of mesenchymal cells that differentiate into endochondral chondrocytes lose DCX expression”

“Dlk1 inhibits in vitro chondrogenesis. The increased Dlk1 level may be needed to antagonize other signals that drive chondrogenesis, so as chondrogenesis occurs in a controlled manner”

“Cytl1-null mice also showed normal endochondral ossification and long bone development. In addition, the ultrastructural features of matrix organization and chondrocyte morphology in articular cartilage were similar between wild-type and Cytl1-null mice. However, Cytl1-null mice were more sensitive to osteoarthritic (OA) cartilage destruction upon destabilization of the medial meniscus of mouse knee joints. Furthermore, the expression levels of Cytl1 were markedly decreased in OA cartilage of humans and experimental mice. ”

“Prrx2 was highly expressed in the distal region compared to the proximal region. It has been reported that Prrx2 is highly expressed in undifferentiated mesenchymal cells and its expression decreases when the mesenchymal cells differentiate into chondrocytes ”

“collagen II is expressed at higher levels in endochondral cartilage than articular cartilage”

Toward regeneration of articular cartilage.

“Articular cartilage is classified as permanent hyaline cartilage and has significant differences in structure, extracelluar matrix components, gene expression profile, and mechanical property from transient hyaline cartilage found in the epiphyseal growth plate. In the process of synovial joint development, articular cartilage originates from the interzone, developing at the edge of the cartilaginous anlagen, and establishes zonal structure over time and supports smooth movement of the synovial joint through life. The cascade actions of key regulators, such as Wnts, GDF5, Erg, and PTHLH, coordinate sequential steps of articular cartilage formation. Articular chondrocytes are restrictedly controlled not to differentiate into a hypertrophic stage by autocrine and paracrine factors and extracellular matrix microenvironment, but retain potential to undergo hypertrophy. The basal calcified zone of articular cartilage is connected with subchondral bone, but not invaded by blood vessels nor replaced by bone, which is highly contrasted with the growth plate. Articular cartilage has limited regenerative capacity, but likely possesses and potentially uses intrinsic stem cell source in the superficial layer, Ranvier’s groove, the intra-articular tissues such as synovium and fat pad, and marrow below the subchondral bone. Considering the biological views on articular cartilage, several important points are raised for regeneration of articular cartilage. We should evaluate the nature of regenerated cartilage as permanent hyaline cartilage and not just hyaline cartilage. We should study how a hypertrophic phenotype of transplanted cells can be lastingly suppressed in regenerating tissue. Furthermore, we should develop the methods and reagents to activate recruitment of intrinsic stem/progenitor cells into the damaged site.”

“The growth plate and the chondroepiphysis consisting of the resting zone of cartilage show significant differences in both elastic module and permeability coefficients: the growth plate is half as stiff as the chondroepiphysis and twice as permeable. Permanent hyaline cartilage and transient hyaline cartilage have differences in mechanical property as well as longevity: the former is more stiff and more resistant to compressive force while the latter is more fragile and short lived.”

“The genes expressed in articular cartilage at higher levels include PRG4 (proteoglycan 4), TNC (tenascin C), GREM1 (Gremlin 1), DKK1 (Dickkopf 1), FRZB (Frizzled-related protein 3), ABI3BP (Abl interactor family member), THBS4 (Thrombospondin-4) and SIX1 (sine-oculis-related homeobox transcription factor), while the genes expressed at much lower levels are hypertrophy related genes such as ALPL (tissue-nonspecific alkaline phosphatase), COL10A1 (collagen 10a1) and PTH1R (PTH/PTHLH receptor).”

“Synovial joint formation generally starts with the appearance of a specific population of mesenchymal cells, called interzone cells, at the future joint site between two cartilaginous skeletal elements”

“The interzone cells are characterized by their histological view, a mass packed with elongated cells sandwiched by cartilaginous anlagen and their gene expression profile that is up-regulation of unique molecules such as Wnt-9a, GDF-5, Erg, Gli-3, CD-44, collagen 2A and collagen 1”

“the superficial layer [of articular cartilage] is a pool of stem cells and supports longitudinal and lateral growth of articular cartilage.”

“chondrocytes in permanent cartilage, including articular chondrocytes, retain the potential to proceed toward hypertrophy and that its potential is negatively regulated under the control of the microenvironment that is established and maintained by a fine balance of extracellular matrix components and structure, contents, and activities of various signaling factors. Ectopic hypertrophy of articular chondrocytes is found together with up-regulation of cartilage matrix metabolism in osteoarthritic cartilage”

“Ectopic expression of Wnt9a or activation of its canonical signaling pathway (Wnt/β-catenin signaling pathway) induces ectopic joint-like structure and expression of joint/articular cartilage markers including GDF5”

“Over-activation of TGFβ1 signaling might also accelerate chondrogenic differentiation of stem/progenitor cells in condyle articular cartilage and induce depletion of this cell population. Wnt/β-catenin signaling would maintain stem/progenitor cells in superficial layer, preventing from chondrogenic differentiation.”

“Transient activation of Wnt/β-catenin signaling increases the depth of superficial layer of articular cartilage.”

“joint distraction seems effectively facilitate cartilage regeneration by itself or in combination with a bone marrow stimulation”