Possible alternative loading device to induce adult height growth?

The key to adult height growth is to induce in vivo chondrogenesis in the bone marrow to get height growth from new endochondral ossification.  LSJL is one method to do such that.  However, there may be another device capable of inducing in vivo chondrogenesis in the bone marrow and therefore other devices capable of adult height growth.

A combination of shear and dynamic compression leads to mechanically induced chondrogenesis of human mesenchymal stem cells.

"Articular motion is a combination of compressive, tensile and shear deformations; therefore, one can presume that compression alone is unlikely to be a sufficient mechanical signal to generate a cartilage-like tissue in vitro[so compressive, tensile, and shear deformations are likely needed to induce chondrogenesis in bone marrow]. we aimed to determine the role of shear on the fate of stem cell differentiation[LSJL induces fluid based shear strain]. Specifically, we investigated the potential enhancing effect of surface shear, superimposed on cyclic axial compression, on chondrogenic differentiation of human bone marrow-derived stem cells. Using a custom built loading device[could this device be an alternative to LSJL?] we applied compression, shear or a combination of both stimuli onto fibrin/polyurethane composites in which human mesenchymal stem cells were embedded, while no exogenous growth-factors were added to the culture medium. Both compression or shear alone was insufficient for the chondrogenic induction of human mesenchymal stem cells. However, the application of shear superimposed upon dynamic compression led to significant increases in chondrogenic gene expression[LSJL should imply both shear and compressive forces.  Axial loading should only apply compressive forces as there is no pressure gradient hence why axial loading does not induce height growth]. Histological analysis detected sulphated glycosaminoglycan and collagen II only in the compression and shear group."

The device is basically a ball placed directly on the mesenchymal stem cells.  I assume to be like the ball of the knee joint.  So the purpose of the ball was for it to oscillate to generate fluid shear strain.

"Group A was the free-swelling (unloaded) control. Group B was exposed to unconfined dynamic compression at 1 Hz with 0.4 mm sinusoidal strain, superimposed on a 0.4 mm static offset strain, resulting in a strain amplitude of 10-20 % of the scaffold height at the centre of the construct. Group C was exposed to ball oscillation of ±25° at 1 Hz, superimposed on a 0.4 mm static compression offset strain. Group D was a combination of both loading regimes. Mechanical load was applied during 1 h a day for 5 consecutive days per week over 3 weeks"<-LSJL loading applies load for slightly over 1 minute which is much less than 1 hour.

"There was a trend towards higher total GAG/DNA values in the loaded groups which included shear[so shear strain is very important for inducing chondrogenesis, axial loading induces no shear strain thus no chondrogenesis], but no significant difference over the compression only group was detected. All individual donors demonstrated the same trend[so all individual bone marrow sources were capable of chondrogenesis]"

Compression and Sox9 groups expressed much more Sox9 than just shear groups alone.  So compressive forces are still important to chondrogenesis.  If you look at Figure 6D in the study you can almost see a growth plate.

What we can take from this study is that maybe the LSJL clamping routine is not dynamic enough at inducing fluid based shear strain.  Perhaps rapid clamping and unclamping would be a way to make LSJL induce more shear forces.

The ball device is not something that could be used as you'd need to put the ball directly against the bone marrow.  Maybe surgically implanting a ball in the bone marrow may be a possibility for the future.