Hydrostatic Pressure may not increase height growth for everyone

Hydrostatic pressure is an important basis for the theory of LSJL.  Could some individuals cells be responsive to hydrostatic pressure while others are not?  Note in the following study 10 MPa is used which is far greater than what can be achieved by a clamp.

The effect of cyclic hydrostatic pressure on the functional development of cartilaginous tissues engineered using bone marrow derived mesenchymal stem cells.

"Mechanical signals can play a key role in regulating the chondrogenic differentiation of mesenchymal stem cells (MSCs)[We are trying to use the mechanical signal of LSJL to induce chondrogenic differentiation of mesenchymal stem cells in the epiphyseal bone marrow]. The objective of this study was to determine if the long-term application of cyclic hydrostatic pressure could be used to improve the functional properties of cartilaginous tissues engineered using bone marrow derived MSCs. MSCs were isolated from the femora of two porcine donors[so pig donors], expanded separately under identical conditions, and then suspended in cylindrical agarose hydrogels. Constructs from both donors were maintained in a chemically defined media supplemented with TGF-β3 for 42 days. TGF-β3 was removed from a subset of constructs from day 21 to 42. Loaded groups were subjected to 10 MPa of cyclic hydrostatic pressurisation at 1 Hz for one hour/day, five days/week. Loading consisted either of continuous hydrostatic pressure (CHP) initiated at day 0, or delayed hydrostatic pressure (DHP) initiated at day 21. Free swelling (FS) constructs were cultured in parallel as controls. Constructs were assessed at days 0, 21 and 42. MSCs isolated from both donors were morphologically similar, demonstrated comparable colony forming unit-fibroblast (CFU-F) numbers, and accumulated near identical levels of collagen and GAG following 42 days of free swelling culture[So the MSCs from different donors responded differently to other variables than hydrostatic pressure].  The two donors displayed a differential response to hydrostatic pressure. For one donor the application of CHP resulted in increased collagen and GAG accumulation by day 42, resulting in an increased dynamic modulus compared to FS controls. In contrast, CHP had no effect on matrix accumulation for the other donor[So for one donor the hydrostatic pressure did not work at enhancing chondrogenic differentiation]. The application of DHP had no effect on either matrix accumulation or construct mechanical properties for both donors[So Hydrostatic Pressure works better at initiating chondrogenic differentiation which is what we're working towards with LSJL]. Variability in the response to hydrostatic pressure was also observed for three further donors. Application of long-term hydrostatic pressure can be used to improve the functional properties of cartilaginous tissues engineered using bone marrow derived MSCs by enhancing collagen and GAG accumulation. The response to such loading is donor dependent."

Since the bone marrow was isolated from the bone itself, it cannot be bone properties that altered the resistance of stem cells to hydrostatic pressure.  Some stem cells must be resistant to the stimulus of hydrostatic pressure to induce cartilage growth.


"Cyclic hydrostatic pressure has been shown to enhance chondrogenesis of MSC aggregates, as evidenced by increases in type II collagen and aggrecan mRNA expression and/or proteoglycan and collagen accumulation"<-MSC aggregates means before any signs of chondrogenesis is detected.  Just if there are sufficient number of MSCs aggregated in a certain area.  Hydrostatic Pressure has the ability to initiate chondrogenesis where there is none which is why it's so powerfully potential to induce height growth.

"It has also been demonstrated that the magnitude of hydrostatic pressure (0.1, 1 or 10 MPa) differentially regulates chondrogenesis of MSC aggregates, with greater type II collagen mRNA expression and collagen accumulation at higher pressures"<-Unfortunately, we are limited in how much hydrostatic pressure we can induce but we will still get some Type II collagen mRNA expression and collagen accumulation.

"In contrast, other studies report that hydrostatic pressure has little or no effect on chondrogenic gene expression or matrix accumulation in MSC aggregates, in either the presence or absence of TGF-β1 or BMP-2. Furthermore, hydrostatic pressure has been shown to have no effect on aggrecan and collagen II mRNA expression for MSCs embedded in agarose hydrogels"<-So hydrostatic pressure does not help induce height growth sometimes.

"The response of stem cells to mechanical signals [may be individual] dependent."<-Some stem cells may not send out chondrogenic signals to hydrostatic pressure which would mean that LSJL would not work for those people.

"Our hypothesis was initially motivated by our previous findings that other forms of mechanical stimulation, specifically dynamic compression, can inhibit chondrogenesis of MSCs if applied before chondrogenesis has occurred"<-Weight lifting is dynamic compression so weight lifting could inhibit chondrogenesis.  This does not affect pubertal growth as the MSCs have already engaged in chondrogenesis although there may be some MSCs that have not yet.

"It may be that 3 weeks of delayed hydrostatic pressure was of insufficient duration, as previous studies have also suggested that multiple days of hydrostatic pressure may be required to enhance chondrogenesis of bone marrow derived MSCs"<-So it's possible that some people may need a longer duration of hydrostatic pressure to experience results.

"MSCs from different donors [respond differently] to cytokine induced chondrogenic differentiation. Animal model studies investigating mechanically induced chondrogenesis in vivo often report dramatic donor dependent response to loading"<-MSCs respond differently to various cytokines and other mechanical signals so responding differently to hydrostatic pressure is not out of the question.

So LSJL may not be effective for some individuals based on the responsiveness of their MSCs to hydrostatic pressure.  Now this might not be solely genetic(which can be altered by the environment as well) but environment.  Some MSCs could become conditioned to hydrostatic pressure or some MSCs might not be sufficiently primed for hydrostatic pressure by exposure to compounds like IGF-1 and Hyaluronic Acid.

We really have to know why some MSCs don't respond to hydrostatic pressure to know how to fix it.


Cell-matrix interactions regulate mesenchymal stem cell response to hydrostatic pressure

"Bone marrow derived MSCs were seeded into either agarose or fibrin hydrogels and exposed to 10 MPa of cyclic HP (1 Hz, 4h/day, 5 days/week for 3 weeks) in the presence of either 1 or 10 ng/ml TGF- 3. Agarose hydrogels were found to support a spherical cellular morphology, while MSCs seeded into fibrin hydrogels attached and spread, with clear stress fiber formation. Hydrogel contraction was also observed in MSC-fibrin constructs. While agarose hydrogels better supported chondrogenesis of MSCs, HP only enhanced sulphated glycosaminoglycans (sGAG) accumulation in fibrin hydrogels, which correlated with a reduction in fibrin contraction. HP also reduced alkaline phosphatase activity in the media for both agarose and fibrin constructs, suggesting that this stimulus plays a role in the maintenance of the chondrogenic phenotype. This study demonstrates that a complex relationship exists between cell-matrix interactions and hydrostatic pressure which plays a key role in regulating the chondrogenic differentiation of MSCs."

Which hydrogel is closer to the epiphyseal bone marrow?

"when MSCs are seeded in RGD-modified alginate hydrogels chondrogenic gene expression and matrix accumulation is inhibited relative to arginine-glycine-glutamic acid (RGE)-modified controls to which MSCs cannot adhere"

"The inhibitory effect of RGD can be blocked with the addition of soluble RGD or cytochalasin D (an F-actin cytoskeleton inhibitor), demonstrating a role for cell attachment and actin cytoskeleton formation in suppressing chondrogenic differentiation"

"an intact dynamic actin cytoskeleton under tension has been shown to be necessary for fluid flow-induced changes in Sox-9 gene expression in MSCs"

"chondrocytes in pellet culture respond more favorably to HP relative to cells embedded in alginate hydrogels"

"In the current study, HP increased sGAG synthesis when MSCs were cultured in the presence of 1 ng/ml TGFBeta- 3 but not 10 ng/ml TGFBeta- 3"<-TGFBeta may affect mechanotransduction.

"long term application of HP (6 weeks) can enhance chondrogenesis of MSCs embedded in agarose hydrogels"

Human cells derived from degenerate intervertebral discs respond differently to those derived from non-degenerate intervertebral discs following application of dynamic hydrostatic pressure.

"The intervertebral disc (IVD) is one of the body's most important load-bearing structures with the major mechanical force experienced in the nucleus pulposus (NP) being hydrostatic pressure (HP). Physiological levels of HP have an anabolic effect on IVD matrix metabolism in cells derived from non-degenerate animal and herniated IVD while excessive HP has a catabolic effect. However, no studies have investigated the response of non-degenerate and degenerate human disc cells derived from non-herniated discs to HP. Here we investigate the effect of physiological HP on such cells using a novel loading rig. Human IVD cells (both NP and AF) cultured in alginate were subjected to dynamic HP (0.8-1.7 MPa 0.5 Hz) for 2 h. Cell viability was assessed, RNA extracted and qRT-PCR for 18 s, c-fos, Sox-9, collagen type II, aggrecan and MMP-3 performed. Cell viability was unaffected by the loading regime. In non-degenerate NP cells, HP increased c-fos, aggrecan, Sox-9 and collagen type II[LSJL increases all of these proteins] (significantly so in the case of c-fos and aggrecan), but not MMP-3{up} gene expression. In contrast, application of HP to AF or degenerate NP cells had no effect on target gene expression. Our data shows that cells obtained from the healthy NP respond to dynamic HP by up-regulating genes indicative of healthy matrix homeostasis. However, responses differed in degenerate NP cells suggesting that an altered mechanotransduction pathway may be operational[so HP won't work if the mechanotransductive mechanisms don't work]."

2.5HP has a catbolic effect whereas lower levels especially 0.25 to 1MPa have an anabolic effect.

"Static pressure of 1.7 MPa was applied for 1 h at room temperature "