Click on the image for a better view.  IGF2 is a strong candidate for increasing height including adults giving it’s role for inspiring progenitor cells that form new growth plates.  The problem is how to increase it.

Target genes for height increase are as follows, for KO genes supplements or activities that inhibit these genes will increase height.  For OE genes supplements or activities that upregulate these genes will increase height.  For biphasic genes both overexpression and knockout decrease height.  There are many biphasic genes but they are not listed.

KO(inhibit these)(Black):
FANCC
NOG
NPR3
RNF135
SOCS2
STC2
GPC3
IGF2R
GPR30
POMC

OE(stimulate these)(Red):
NPPC
PLAG1
SHOX2
Twist1
CNP
IGF2
IGF1
Akt1
CTGF(CCN2)

Notice how close four genes are in proximity to IGF2: IGF2R, GPC3, POMC, GPER.  NPPC has a direct relationship with NPR3 with NPPC increasing height and NPR3 decreasing height.  IGF2 is a strong central locus for increasing height also being connected to IGF1 and Akt1.  LSJL increases Akt-phosphorylation by the way.

It turns out that the growth plate will regrow as long as their are progenitor cells, this area is called the zone of Ranvier.  IGF2 could play a role in making these growth plate progenitor cells.

Since IGF2 is such a strong target for height growth how can we increase IGF2 levels for height?

Loss of imprinting of IGF2 and the epigenetic progenitor model of cancer.

“While IGF2 usually supports normal cellular growth, LOI of IGF2 may lead to overexpression of the gene and moreover global chromatin instability.”

“differentiated cells present in adult tissue that can acquire the ability to become undifferentiated and behave like stem cells, or progenitor cells”

” In contrast to mutations in the genetic sequence of DNA, epigenetic changes occur beyond the level of DNA and alter the protein-DNA complex that forms chromosomes. One such epigenetic factor is parental imprinting”

“Insulin-like growth factor 2 (IGF2), a gene whose end action is to stimulate general growth, is usually imprinted such that only the paternal allele is expressed. When LOI occurs, the maternal allele may also be expressed and some studies have, indeed, correlated LOI of IGF2 with increases in expression“<-So we can cause Loss of imprinting in adults to increase IGF2 expression in adults.

“The ICR for the IGF2/H19 locus is located in the 5’ flanking region of the H19 gene and 90kb downstream of IGF2. The ICR on the maternal allele is unmethylated, while the ICR on the paternal allele is methylated. This methylation of the paternal allele ICR blocks the transcription factor CCCTC-binding factor (CTCF) from binding and creating a physical barrier that stops downstream enhancers from augmenting IGF2 promoters. This effectively silences the maternal allele”

“Mouse models have shown that CTCF binds to regions near the IGF2 promoter, as well as the ICR, and subsequently forms CTCF-CTCF dimers, creating an intrachromosomal loop. The CTCF dimer then interacts with the SUZ12 (suppressor of zeste 12 homolog) domain of polycomb repressive complex 2 (PRC2) which methylates histone H3 lysine residue 27 (H3K27) causing silencing of the maternal allele.  CTCF [synthesizes] decoy CTCF proteins. When introduced to cells, the decoys bind to the unmethylated ICR and IGF2 promoter but do not interact with SUZ12, thereby rendering Enhancer of zeste homolog 2 (EZH2), another part of PRC2, unable to methylate histone H3K27, resulting in reactivation of the imprinted allele{so the decoy CTCF are key to causing loss of imprinting of IGF2}. Neither intact CTCF sites nor hypermethylation at the ICR is sufficient for maintaining paternal allele silencing, and sequences outside of the CTCF binding sites at the ICR are needed for silencing”

“Thus, LOI of IGF2 may result from a variety of causes including: aberrant ICR methylation, a decreased expression of PRC2, a mutation of the ICR, or altered PRC2 H3K27 methylation. In contrast to the maternal allele, the paternal ICR is methylated, thereby blocking CTCF and PRC2 binding”

“A two-fold increase in IGF2 expression results in a 131% increase in offspring growth. Circulating IGF2 ligand has been shown to regulate crosstalk between the WNT and IGF1R pathways, which can lead to activation of either the phosphoinositide 3-kinase (PI3K)-AKT or the Ras-MAPK (mitogen-activated protein kinase) pathways that control metabolism, growth, differentiation, and apoptosis ”

“IGF2 expression levels thirty fold higher than wild type were not sufficient to develop tumors until senescence.”<-Elevated IGF2 levels do not directly cause cancer.  Just more cells = more opportunities for malfunction=increased likelihood for cancer.

“LOI of IGF2 causes a bi-allelic expression of the gene, resulting in the overexpression of the IGF2 protein”

” a diet lacking synthetic methyl donors, including folic acid, vitamin B12, choline, and methionine, could cause LOI of IGF2 in murine models”<-Not really something you want to do however.

IGF2 injections were shown to induce height growth in an LSJL related study.

There are no known supplements that increase IGF2 in humans and I don’t know of any therapies involving injections.

Using CTCF decoy proteins may be a way though:

Interruption of intrachromosomal looping by CCCTC binding factor decoy proteins abrogates genomic imprinting of human insulin-like growth factor II.

“Monoallelic expression of IGF2 is regulated by CCCTC binding factor (CTCF) binding to the imprinting control region (ICR) on the maternal allele, with subsequent formation of an intrachromosomal loop to the promoter region. The N-terminal domain of CTCF interacts with SUZ12, part of the polycomb repressive complex-2 (PRC2), to silence the maternal allele. We synthesized decoy CTCF proteins, fusing the CTCF deoxyribonucleic acid-binding zinc finger domain to CpG methyltransferase Sss1{not an easy thing to do homemade} or to enhanced green fluorescent protein. In normal human fibroblasts and breast cancer MCF7 cell lines, the CTCF decoy proteins bound to the unmethylated ICR and to the IGF2 promoter region but did not interact with SUZ12. EZH2, another part of PRC2, was unable to methylate histone H3-K27 in the IGF2 promoter region, resulting in reactivation of the imprinted allele. The intrachromosomal loop between the maternal ICR and the IGF2 promoters was not observed when IGF2 imprinting was lost. CTCF epigenetically governs allelic gene expression of IGF2 by orchestrating chromatin loop structures involving PRC2.”

” A maternally transmitted microdeletion of two CTCF binding sites in the ICR results in biallelic IGF2 expression and H19 silencing in Beckwith-Wiedemann syndrome”<-A syndrome that results in increased height.

Here’s a paper that states that Paxillin could be involved in IGF2 related growth:

Paxillin-dependent regulation of IGF2 and H19 gene cluster expression.

“Paxillin (PXN) is a focal adhesion protein that has been implicated in signal transduction from the extracellular matrix. Recently, it has been shown to shuttle between the cytoplasm and the nucleus. When inside the nucleus, paxillin promotes cell proliferation. Here, we introduce paxillin as a transcriptional regulator of IGF2 and H19 genes. It does not affect the allelic expression of the two genes; rather, it regulates long-range chromosomal interactions between the IGF2 or H19 promoter and a shared distal enhancer on an active allele. Specifically, paxillin stimulates the interaction between the enhancer and the IGF2 promoter, thus activating IGF2 gene transcription, whereas it restrains the interaction between the enhancer and the H19 promoter, downregulating the H19 gene. We found that paxillin interacts with cohesin and the mediator complex, which have been shown to mediate long-range chromosomal looping. We propose that these interactions occur at the IGF2 and H19 gene cluster and are involved in the formation of loops between the IGF2 and H19 promoters and the enhancer, and thus the expression of the corresponding genes. These observations contribute to a mechanistic explanation of the role of paxillin in proliferation and fetal development.”

“focal adhesion proteins can be found not only at focal adhesion contacts but also inside the nucleus and they can shuttle out of it and back in”

” The block of CRM1-dependent export pathway causes accumulation of paxillin inside the nucleus ”

“reactivation of IGF2 expression on the maternal allele has been previously reported in a number of human tumors and tumor cell lines”<-controlled reactivation could help us grow taller.

“SMC1A and MED23 play a role in paxillin-dependent regulation of the H19–IGF2 gene cluster. ”

 An essential role for IGF2 in cartilage development and glucose metabolism during postnatal long bone growth.

“Postnatal bone growth involves a dramatic increase in length and girth. Intriguingly, this period of growth is independent of growth hormone and the underlying mechanism is poorly understood. Recently, an IGF2 mutation was identified in humans with early postnatal growth restriction. Here, we show that IGF2 is essential for longitudinal and appositional murine postnatal bone development, which involves proper timing of chondrocyte maturation and perichondrial cell differentiation and survival. Importantly, the Igf2 null mouse model does not represent a simple delay of growth but instead uncoordinated growth plate development. Furthermore, biochemical and two-photon imaging analyses identified elevated and imbalanced glucose metabolism in the Igf2 null mouse. Attenuation of glycolysis rescued the mutant phenotype of premature cartilage maturation, thereby indicating that IGF2 controls bone growth by regulating glucose metabolism in chondrocytes. This work links glucose metabolism with cartilage development and provides insight into the fundamental understanding of human growth abnormalities.”

“Newly formed chondrocytes are proliferative and morphologically round, but eventually become flat chondrocytes to form the ‘columnar zone’”

“the Igf2 null growth plate cartilage was shorter and disproportionally thinner than the WT.  The mutant growth plate was generally well formed, but its hypertrophic zone was disproportionally larger and the epiphyseal zone shorter. In addition, there was a clear delay in SOC formation in the mutant, which contributed to the shortened cartilage template ”

“IGF2 deficiency caused a shortening of the prehypertrophic zone ”

” Our prior study on human adult articular chondrocytes also failed to detect Akt activation by IGF2, suggesting that IGF2 may act differently than IGF1 in chondrocytes ”

“the regulatory role of IGF2 on chondrocyte maturation and matrix production in endochondral ossification is mediated by its activity on glucose metabolism in chondrocytes.”

“TheIgf1r null mouse has shorter bones, but the IR null mouse has a normal bone length.  However, both knockouts had a reduced hypertrophic zone which is consistent with the phenotype of the Igf1 knockout.  Igf2 null bones, on the other hand, exhibit a disproportionally larger hypertrophic zone. These data indicate different roles of IGF1 and IGF2 on cartilage development. Consistent with this notion, although IGF2 overexpression promoted postnatal growth, it failed to compensate the phenotype caused by the loss of IGF1 ”

“IGF2 is unique in its ability to bind to IGF2R, and it has been shown that the direct binding of IGF2 to IGF2R stimulated proteoglycan synthesis and induced calcium influx in chondrocytes, as it occurs even in the presence of an antiIGF-IR antibody.On the other hand, knockout of Igf2r exhibits increased skeletal growth{Maybe because this encourages IGF2 to bind to different receptors? Thus,none of the single knockout of the potential receptors exhibits the same phenotype as that of the Igf2 null mouse. However, it is possible that the phenotype of the Igf2 null mouse is a result of its binding to multiple receptors, together with interaction of multiple IGF-binding proteins and subsequent complex downstream signaling”

Inhibiting Phd2 may be a potential drug target to help people grow taller.

Conditional Deletion of Prolyl Hydroxylase Domain-containing Protein 2 (Phd2) Gene Reveals its Essential Role in Chondrocyte Function and Endochondral Bone Formation.

“The hypoxic growth plate cartilage requires hypoxia-inducible factors (HIFs)-mediated pathways to maintain chondrocyte survival and differentiation. HIF proteins are tightly regulated by prolyl hydroxylase domain-containing protein 2 (Phd2) mediated proteosomal degradation. We conditionally disrupted the Phd2 gene in chondrocytes by crossing Phd2 floxed mice with Col2α1-Cre transgenic mice, and found massive increases (>50%) in the trabecular bone mass of long bones and lumbar vertebra of the Phd2 conditional knockout (cKO) mice caused by significant increases in trabecular number and thickness and reductions in trabecular separation. Cortical thickness and tissue mineral density at the femoral mid-diaphysis of the cKO mice were also significantly increased. Dynamic histomorphometric analyses revealed increased longitudinal length and osteoid surface per bone surface (OS/BS) in the primary spongiosa of the cKO mice, suggesting elevated conversion rate from hypertrophic chondrocytes to mineralized bone matrix as well as increased bone formation in the primary spongiosa. In the secondary spongiosa, bone formation measured by MS/BS and MAR were not changed but resorption was slightly reduced. Increases in the mRNA levels of Sox9, Osterix (Osx), Col2, Aggrecan, ALP, Bsp, VEGF, Epo, and glycolytic enzymes in the growth plate of cKO mice were detected by quantitative RT-PCR. Immunohistochemistry revealed an increased HIF-1α protein level in the hypertrophic chondrocytes of cKO mice. Infection of chondrocytes isolated from Phd2 floxed mice with adenoviral Cre resulted in similar gene expression patterns as observed in the cKO growth plate chondrocytes. Our findings indicate that Phd2 suppresses endochondral bone formation, in part, via HIF-dependent mechanisms in mice.”

“hypertrophic chondrocytes can transdifferentiate into osteoblasts and contribute to trabecular, endosteal, and cortical bone formation”

“In chondrocytes, HIF-1 increases the expression of VEGF and promotes angiogenesis in the
surrounding perichondrium ”

Only deletion of Phd2 in chondrocytes seems to increase height.  Deletion of Phd2 in say osteoblasts seems to decrease height.  Also Phd2 cKo seems to result in shorter overall body length. It’s just the primary spongosia that’s increased in length.

Bmpr1a is downregulated by aging in bone marrow.  LSJL upregulates Bmpr1b but expression of Bmpr1a is modulated by normal mechanical loading.  BMP-2 interacts with Bmpr1a.  LSJL upregulates BMP-2.  Cells in the perichondrial groove express Bmpr1a.  Persistent upregulation of Hoxa2 which causes short stature downregulates Bmpr1a.  Bmpr1a is upregulated in a fractured tibia.  These facts are consistent with the observation that bmpr1a could play an on/off-switch in neo-growth plate formation.

BMP Receptor 1A Determines the Cell Fate of the Postnatal Growth Plate.

“Embryos deficient in Bmp receptor (Bmpr)1a or Bmpr1b in cartilage display subtle skeletal defects; however, double mutant embryos develop severe skeletal defects, suggesting a functional redundancy that is essential for early chondrogenesis. In this study, we examined the postnatal role of Bmpr1a in cartilage. In the Bmpr1a conditional knockout (cKO, a cross between Bmpr1a flox and aggrecan-CreER (T2) induced by a one-time-tamoxifen injection at birth and harvested at ages of 2, 4, 8 and 20 weeks), there was essentially no long bone growth with little expression of cartilage markers such as SOX9, IHH and glycoproteins. Unexpectedly, the null growth plate was replaced by bone-like tissues, supporting the notions that the progenitor cells in the growth plate, which normally form cartilage, can form other tissues such as bone and fibrous; and that BMPR1A determines the cell fate. ”

“During endochondral ossification, the progenitor cells committed act as the stem cells that replenish the pool of proliferative chondrocytes in the resting zone of the growth plate. The resulting daughter cells exit the cycle and undergo maturation via prehypertrophic, hypertrophic and terminal hypertrophic processes, followed by calcified cartilage formation. The vascular invasion then leads to the removal of cartilage, formation of bone marrow, and new bone formation and growth.”

“Is [there] a molecule that initiates and guides the progenitor cell in the resting zone of the growth plate, which solely differentiates chondrogenesis?”<-We want to find this molecule and induce it in adult bone.

” The failure of long bone growth indicates that there is no new progenitor cells added after deletions of Bmpr1a gene by one time injection of tamoxifen at newborn stage.”<-This is bad news that there may be a fixed pool of progenitor cells that is used up.  However, other stem cells could become progenitor cells after the right mechanical stimulus.

“The work with a one-time injection of tamoxifen to remove Bmpr1a in cartilage at birth, which leads to a lack of long bone growth postnatally, raises the possibility that the progenitor cell number might already be present in the growth plate at birth with no more new progenitor cells added. This observation may explain why the rodent growth plate remains unfused during the animal’s lifetime but there is essentially no long bone lengthening after 28-30 weeks. In fact, in the 5-month-old control mouse, there is very limited cell proliferation in the growth plate compared to the early stage ”

So the goal in a bone lengthening program is to alter cell morphology of stem cells to be more like the progenitor cells present in the zone of ranvier and then to upregulate bmpr1a expression to encourage a chondrogenic fate.

This fixed pool of progenitor cells is also supported by s1p-ko mice which can form new growth plates from this pool of progenitors.

IGF-2 could play a role in priming MSCs to be more like the progenitor cells that form new growth plates.  IGF-2 has been used to induce longitudinal bone growth.  The LSJL scientists have also suggested that IGF-2 injections may be beneficial to LSJL lengthening.  CTGF is linked to IGF2 and is another target to increase for supplements as well as HMGA2.  IGF2 is downregulated almost 1000-fold during senescence which further links IGF2 to the creation of progenitor cells.

I couldn’t find any supplements that increase IGF-2.  There’s a supplement called IGF-2 but that just seems to be the brand name.

Epigenetic consequences of a changing human diet.

“The ultimate methyl donor for epigenetic-methylation reactions is S-adenosylmethionine that is produced by the methylation cycle and it has been reported that periconceptional folic acid use alters the level of methylation within IGF2. A larger study of human pregnancy also observed an effect of folic acid use on IGF2 methylation in the offspring but the effect was restricted to folic acid use after 12 weeks gestation when women are not recommended to take the supplement. Late gestation use of folic acid was also associated with reduced LINE-1 methylation and altered paternally expressed gene 3 (PEG3) methylation. Three of the four significant associations with folic acid use and folate status were negative and one was positive, suggesting that it may be naive to assume that this is a simple substrate limitation effect or that the supply of nutrients involved in the methylation cycle will affect all genes equally.
Imprinting occurs before fertilisation but changes in imprinting methylation in animal models in response to nutritional exposures have been demonstrated into the early post-natal period for IGF2, after which the imprint is apparently fixed”

Choline can result in hypermethylation of IGF2 in the liver.  Liver production of IGF2 is not stimulated by GH in adult mammals.  In adult mammals, IGF2 does not seem to respond to physiological status or vary with growth rate.

Expression of bone-related genes in bone marrow MSCs after cyclic mechanical strain: implications for distraction osteogenesis.

“In this study, a single period of cyclic mechanical stretch (0.5 Hz, 2,000 microepsilon) [for 40 minutes] was performed on rat bone marrow MSCs. Cellular proliferation and alkaline phosphatase (ALP) activity was examined. The mRNA expression of six bone-related genes (Ets-1, bFGF, IGF-II, TGF-beta, Cbfa1 and ALP) was detected using real-time quantitative RT-PCR.
The results showed that mechanical strain can promote MSCs proliferation, increase ALP activity, and up-regulate the expression of these genes. A significant increase in Ets-1 expression was detected immediately after mechanical stimulation, but Cbfa1 expression became elevated later. The temporal expression pattern of ALP coincided perfectly with Cbfa1.
The results of this study suggest that mechanical strain may act as a stimulator to induce differentiation of MSCs into osteoblasts{but could be chondrocytes with increase in bmpr1a levels}.”

This was the load applied to the cells during the study it’s reasonable to expect that the load is similar to that which is applied by LSJL.

“The transcription profiles of IGF-Ⅱand TGF-β were similar. Both genes reached maximum transcription immediately after mechanical strain and mRNA levels then decreased with time, except for a slight increase at 6 hours.”

The age of rats is not given and is vital information given that IGF2 is an age related gene.

It’s conceivable that LSJL modulates Bmpr1a expression given the study that shown it can be modified by mechanical loading and that LSJL modulates IGF2 expression given the study above that showed that it was upregulated by mechanical loading.

But still finding supplements that upregulate IGF2 and Bmpr1a would be exceptionally helpful.

Biomechanical and biophysical environment of bone from the macroscopic to the pericellular and molecular level.

“Bones with complicated hierarchical configuration and microstructures constitute the load-bearing system. Mechanical loading plays an essential role in maintaining bone health and regulating bone mechanical adaptation (modeling and remodeling). The whole-bone or sub-region (macroscopic) mechanical signals, including locomotion-induced loading and external actuator-generated vibration, ultrasound, oscillatory skeletal muscle stimulation, etc., give rise to sophisticated and distinct biomechanical and biophysical environments at the pericellular (microscopic) and collagen/mineral molecular (nanoscopic) levels, which are the direct stimulations that positively influence bone adaptation. While under microgravity, the stimulations decrease or even disappear, which exerts a negative influence on bone adaptation. A full understanding of the biomechanical and biophysical environment at different levels is necessary for exploring bone biomechanical properties and mechanical adaptation. In this review, the mechanical transferring theories from the macroscopic to the microscopic and nanoscopic levels are elucidated. First, detailed information of the hierarchical structures and biochemical composition of bone, which are the foundations for mechanical signal propagation, are presented. Second, the deformation feature of load-bearing bone during locomotion is clarified as a combination of bending and torsion rather than simplex bending. The bone matrix strains at microscopic and nanoscopic levels directly induced by bone deformation are critically discussed, and the strain concentration mechanism due to the complicated microstructures is highlighted. Third, the biomechanical and biophysical environments at microscopic and nanoscopic levels positively generated during bone matrix deformation or by dynamic mechanical loadings induced by external actuators, as well as those negatively affected under microgravity, are systematically discussed, including the interstitial fluid flow (IFF) within the lacunar-canalicular system and at the endosteum, the piezoelectricity at the deformed bone surface, and the streaming potential accompanying the IFF. Their generation mechanisms and the regulation effect on bone adaptation are presented. The IFF-induced chemotransport effect, shear stress, and fluid drag on the pericellular matrix are meaningful and noteworthy. Furthermore, we firmly believe that bone adaptation is regulated by the combination of bone biomechanical and biophysical environment, not only the commonly considered matrix strain, fluid shear stress, and hydrostatic pressure, but also the piezoelectricity and streaming potential. Especially, it is necessary to incorporate bone matrix piezoelectricity and streaming potential to explain how osteoblasts (bone formation cells) and osteoclasts (bone resorption cells) can differentiate among different types of loads. Specifically, the regulation effects and the related mechanisms of the biomechanical and biophysical environments on bone need further exploration, and the incorporation of experimental research with theoretical simulations is essential.”

“bone  adaptation is regulated by the combination of bone biomechanical and biophysical environment, not only the commonly considered matrix strain, fluid shear stress, and hydrostatic pressure, but also the piezoelectricity and streaming potential”

“At the macroscopic level in long bone such as the femur, cortical bone with compact structures
and low porosity forms the hard shell, and trabecular bone with a three-dimensional interconnected  network of trabecular rods and plates forms the inner surface.  In flat bone, e.g. the calvaria and iliac crest, the cortical bone and trabecular bone form the cortical-trabecular-cortical sandwich structure”

the pericellular spaces between osteocytes and the lacunar-canalicular wall are filled with interstitial fluid and pericellular matrix (PCM), which is a gel-like fiber matrix thought to be composed of proteoglycans and other matrix molecules ”

” Due to  the low permeability of mineralized bone matrix, interstitial fluid flow (IFF) is principally generated during alteration of intramedullary pressurization (ImP) and bone matrix deformation ”

” Uniform pressurization [such as that due to decreased intramedullary cavity resulting from elevated bone marrow lipids induced by high level of corticosteroid administration will generate radial flow from the intramedullary compartment to the endosteal surface and into the LCS due to the pressure gradient from the marrow cavity to the bone matrix”

” Non-uniform pressure gradients within the intramedullary cavity [such as those due to local heterogeneous permeability or fluid displacement changes in the intramedullary compartment from the interaction between mechanical loading/oscillatory muscle stimulation and capillary filtration in bone tissue  will cause tangential fluid flow to the endosteal surface ”

“The matrix deformation generated pressure gradient within LCS stimulates the interstitial fluid to move towards the lower pressure zone”

“the profiles of IFF within the LCS are sophisticated and can be considered as a combination of
oscillating and unidirectional fluid flow ”

“Three stimuli induced by fluid flow, namely chemotransport effects, IFF-induced shear stress, and fluid drag on the PCM, have been shown to regulate osteocyte activity”

“IFF within the LCS serves as the primary transport mechanism between the blood supply and osteocytes. Furthermore, the shear stress induced by IFF provides potent mechanical stimulation for osteocytes ”

” In the inverse piezoelectric effect, subjecting bone to an electric field induces deformation”

“varying degrees of deformations, or even irreversible deformations, will also be evoked in collagen fibrils and mineral crystals oriented in different directions”

Development of a Portable Knee Rehabilitation Device That Uses Mechanical Loading

development of portable knee device<-Full study there

“Joint loading is a recently developed mechanical modality, which potentially provides a therapeutic regimen to activate bone formation and prevent degradation of joint tissues. Few joint loading devices are available for clinical or point-of-care applications. Using a voice-coil actuator, we developed an electromechanical loading system appropriate for human studies and preclinical trials that should prove both safe and effective. Two specific tasks for this loading system were development of loading conditions (magnitude and frequency) suitable for humans, and provision of a convenient and portable joint loading apparatus. Desktop devices have been previously designed to evaluate the effects of various loading conditions using small and large animals. However, a portable knee loading device is more desirable from a usability point of view. We present a device that is designed to be portable, providing a compact, user-friendly loader. The portable device was employed to evaluate its capabilities using a human knee model. The portable device was characterized for force-pulse width modulation duty cycle and loading frequency properties. The results demonstrate that the device is capable of producing the necessary magnitude of forces at appropriate frequencies to promote the stimulation of bone growth and which can be used in clinical studies for further evaluations.”

Note how the device looks like a table clamp:

“Dynamic loads applied laterally to the knee joint have been found to stimulate new bone formation not only in the distal femur and proximal tibia epiphyses, but along the entire length of each bone.”

“Knee loading is applied laterally to the epiphysis of the femur and tibia, which consist mostly of trabecular bone modeled to resist axial stresses{if the trabecular bone is modeled to resist axial strain than it is less resistant to lateral strain}. This allows greater deformations than are possible with similar loads in different loading modalities.  Dynamic deformations of the epiphysis cause alterations in fluid pressure in the intramedullary cavity, driving oscillatory fluid flow and molecular transport in the lacunocanalicular network in the bone matrix and in the medullary cavity”<-It is alterations in fluid pressure that could induce chondrogenic differentiation of the MSCs in the epiphysis forming new micro growth plates.

“The device applies cyclic loading of magnitudes up to 30N at frequencies ranging from 1 to 20 Hz and can cause small deformation in the knee.”

“The device proposed in this paper differs [from LIPUS and PEMF] in that it stimulates the bone tissue through direct mechanical loading at low frequencies.”

“A cyclic force applied on [the knee] would force a slight shift of the fluid within the bone towards the opposite end of the bone in a controlled fashion.”

“The device must provide sufficient force in a transverse load to the joint without being bulky or unbalanced.”<-This is a problem we may have too.  We might have to use a larger clamp for the knee.  The standard c-class clamp may work for smaller joints but a larger clamp may perform better for the knee.

“The force magnitudes that the device can produce must be at least 30 N”

“power generation units used in conjunction with a mechanism comprised of linkages was proposed as a means of shifting the power generation component into a position that allowed for better balance.”

“Operating the device at frequencies between 1 and 5 Hz is meant to simulate the therapeutic and rehabilitative effects of walking or running without the need to put the patient’s weight on the leg.”<-But would the effect be more significant than walking or running?  Walking and running have a lot of evidence showing that they don’t make you taller.

“the motor shaft is acting as the sliding block while the linkage connecting to the base plate serves as the crank. The rigid pivot arm that connects the motor shaft and crank before ultimately connecting with the pad at the top is the connecting arm.”<-much like a table clamp.

“Aluminum was chosen for the base plate, side plates, and the adjustable side as it is lightweight, but still provides the necessary strength. The pivot arm and lever arm were made of O1 steel. O1 steel has a high carbon content and a correspondingly high modulus of elasticity. This is crucial as these parts are subjected to higher stresses than are found in any other part of the device; it is important to minimize the deflection in these pieces since deflection of these parts would directly affect the range of displacement provided by the mechanism and may also contribute to damping{a decrease in the amplitude of an oscillation as a result of energy being drained from the system to overcome frictional or other resistive forces.}. High density polyethylene was selected for the pads as it allows a slight amount of deformation to increase comfort to the user while still being sufficiently rigid to transfer most of the force to the knee being loaded.”<-Could be helpful in designing a self-made LSJL device

“For the static loading, a 6.9 kPa pressure is evenly distributed across the 64.5 cm2 surface of both side of the pads directed outwards. A 44.5 N force is applied to the center of the motor shaft pushing away from the motor. This loading simulates the force applied by the motor and the reaction on the pads from the knee being loaded. “<-a lot of studies make it clear though that dynamic load is needed.

According to figure 11, Pressure generated is 6000Pa Or 0.006MPa.  Most figures show 0.1 to 10 MPA is what’s needed for chondroinduction but perhaps the pressure generated on the outside is not reflective of the pressure generated inside the bone which could be higher.

Here’s some force generated measurements:

Here’s some displacement measurements:

“the force and corresponding displacement [of the artificial knee] over a period of five cycles at duty cycles of 50% and duty cycles of 100%. Such experiments when performed on an actual knee could be used to assist in the study of the force versus displacement of human tissue, a highly nonlinear reaction, as well as the effects of light mechanical loading to the bone tissue.”

The mechanics definition of displacement is the final position of a point (Rf) relative to its initial position (Ri).  Tissue displacement refers to the change in the form or position of the tissues as a result of pressure.  So the displacement of the artificial knee was about 2.5mm when the force generated was about 30N.  Since the displacement turns to normal it is referred to as an elastic deformation a plastic deformation would be a permanent change.  Thus the only way this device can induce new longitudinal bone growth is if it stimulates neo-endochondral ossification.

Here’s some information about the effects of tissue deformation on tissue deformation from a paper called Biomechanics of Tissues from the Journal of Rheumatology: “In a creep test, an instantaneous step or ramp load is applied to the tissue sample and held constant for an extended period of time. This is considered a load control test, and the resulting tissue displacement is measured. The displacement shows an initial elastic response of the tissue followed by a gradual increase of lengthening of the tissue. As the test proceeds, fluid is exuded from the tissue, and the solid components of the tissue are supporting the applied load. A “solid-like” material will be distracted to a point at which the solid components of the tissue will balance the applied load and will not elongate further. The modulus of the tissue is calculated as the stress of the tissue divided by the end displacement of the tissue. A “fluid-like” material will not be able to balance the applied load and will continue to elongate.“<-I don’t believe this occurred during my LSJL finger lengthening as the fingers increased in width greatly as well.

No mention of using the device for lengthening.  The basis of using LSJL on lengthening is based on studies that show that hydrostatic pressure can induce chondrogenic differentiation and that LSJL upregulates genes that do not only stimulate chondrogenesis of chondrogenitors but also of MSCs such as FGF-2, Gli3, and Cyr61 and of signs of mesenchymal condensation in LSJL images.  Also, in those images is apparent degradation of trabecular bone which would be permissive to neo-growth plate formation.

The condensed stem cells in the images are most consistent with granulocytes which are capable of chondrogenic differentiation.  According to Comparative study of the biological characteristics of mesenchymal stem cells from bone marrow and peripheral blood of rats., peripheral blood MSCs are more chondrogenic than bone marrow MSCs but chondrogenesis of bone marrow MSCs is not impossible.

This study does not provide more evidence that LSJL can increase length but it does support the notion that a table clamp is a perfect home made solution for performing LSJL.

Here’s a study with more about the effects of tissue deformation on the joint region:

The effects of manual therapy on connective tissue<-connective tissue therapy

“a low level of CT[connective tissue] damage must occur in order to produce permanent elongation. The collagen breakage will be followed by a classical cycle of tissue inflammation, repair, and remodeling”<-This paper doesn’t mention cartilage specifically but it mentions other tissues made of collagen fibers.

“Connective tissue that is loaded more quickly will behave more stiffly (will deform less) than
the same tissue that is loaded at a slower rate”

In figure 5, a graph is shown where it appears that microfailure of a tissue(the kind of stimulus that must occur in order to generate permanent lengthening of connective tisues) occurs 4-6mm(with a safer region being between 4-4.5mm) of displacement beyond which is complete failure of the tissue.  The displacement generated by the LSJL device is 2.5mm which is below this level to generate permanent lengthening of connective tissues.

Michael has explored human limb regeneration for height increase in the past.

Retinoic Acid is mentioned as a key to human limb regeneration and p53 has been implicated as being modified by Retinoic Acid in a number of studies.  If we can find a protein link such as p53 that is important to limb regeneration and supplements to modify expression of that protein than perhaps we can use that information to grow taller.

In one instance, p53 activation due to Endoplasmic Reticulum stress resulted in dedifferentiation of hypertrophic chondrocytes into proliferative chondrocytes.  The p53 pathway can be activated by a variety of oxidative and mechanical stresses.  Since activation of p53 is so common it’s unlikely that stimulating p53 is key to stimulating the processes of limb regeneration.  p53 activation is likely a necessary but not sufficient condition.

Regulation of p53 is critical for vertebrate limb regeneration.

“Extensive regeneration of the vertebrate body plan is found in salamander and fish species. In these organisms, regeneration takes place through reprogramming of differentiated cells, proliferation, and subsequent redifferentiation of adult tissues{so humans are likely missing one of these stages likely the reprogramming, can we induce this reprogramming with physical stimulus or supplements?}. Such plasticity is rarely found in adult mammalian tissues, and this has been proposed as the basis of their inability to regenerate complex structures.  Here, we analyzed the role of the tumor-suppressor p53 during salamander limb regeneration. The activity of p53 initially decreases and then returns to baseline. Its down-regulation is required for formation of the blastema, and its up-regulation is necessary for the redifferentiation phase{Since MAPK p38 activates p53, MAPK p38 levels may need to have similar trends as p53 levels during chondrogenic differentiation}. Importantly, we show that a decrease in the level of p53 activity is critical for cell cycle reentry of postmitotic, differentiated cells, whereas an increase is required for muscle differentiation. In addition, we have uncovered a potential mechanism for the regulation of p53 during limb regeneration, based on its competitive inhibition by ΔNp73. The regulation of p53 activity is a pivotal mechanism that controls the plasticity of the differentiated state during regeneration.”

To form a new growth plate you don’t necessarily have to form a blastema, thus reducing p53 levels may not be required.  Just inducing chondrogenic differentiation in MSCs may be enough.

“In salamanders, such as the newt and axolotl, limb regeneration depends on the formation of
a blastema, a mound of progenitor cells of restricted potential that arises after amputation. Following a period of proliferation, blastema cells redifferentiate and restore the structures of the limb.”

“Upon amputation, muscle, cartilage, and connective tissue cells underneath the injury site lose their differentiated characteristics and reenter the cell cycle to give rise to the blastema”

“inhibiting p53 disrupts limb regrowth in salamanders”

“a decrease in the expression levels of Gadd45 and Mdm2 between the early (9 d postamputation, dpa) and late (18 dpa) bud stages, corresponding to the period of blastema formation, followed by a return to the initial levels upon redifferentiation”

“α-pifithrin [is] a p53 inhibitor and nutlin3a [is] a p53 stabilizer, which disrupts the p53–Mdm2 interaction”

“Stabilization of the p53 level at the time of blastema formation, when it normally decreases, led to an impairment of the regeneration process”

“[There exists] upper and lower thresholds of p53 activity, above or below which blastema formation is impaired.”

“the overexpression of the p53 dominant-negative construct DDp53, from the mid-bud stage onwards, resulted in delayed and defective regeneration”<-But not completely absent which means that if a way to inhibit p53 is not found it does not mean completely inhibited regeneration.

“[UV light results] in p53 stabilization and up-regulation of Gadd45 [in both humans and salamanders]”

P53 levels are self reduced because p53 produces MDM2 which degrades p53.  Unless there is oxidative or mechanical stress, p53 levels tend to degrade.  Perhaps this is why spontaneous chondrogenic differentiation can occur in microgravity where there are no oxidative and mechanical stresses?