Mechanical Loading on Tendons(Some evidence for Entheses LSJL)

Considering the alternative LSJL method relies on pushing two bones against one other at ligament and tendon attachment sites, understanding how mechanical loading affects tendons is important.

The effects of mechanical loading on tendons–an in vivo and in vitro model study.

“Mechanical loading constantly acts on tendons. [We] investigate tendon mechanobiological responses through the use of mouse treadmill running as an in vivo model and mechanical stretching of tendon cells as an in vitro model. Mice underwent moderate treadmill running (MTR) and intensive treadmill running (ITR) regimens. Treadmill running elevated the expression of mechanical growth factors (MGF) and enhanced the proliferative potential of tendon stem cells (TSCs) in both patellar and Achilles tendons. In both tendons, MTR upregulated tenocyte-related genes: collagen type I (Coll. I ∼10 fold) and tenomodulin (∼3-4 fold), but did not affect non-tenocyte-related genes: LPL (adipocyte), Sox9 (chondrocyte){this is the gene were are looking for}, Runx2 and Osterix (both osteocyte). However, ITR upregulated both tenocyte (Coll. I ∼7-11 fold; tenomodulin ∼4-5 fold) and non-tenocyte-related genes (∼3-8 fold){so the load has to be sufficient to affect the target chondrogenic gene for our purposes.  If the load is not intense enough it will not upregulate novel genes.}. In the in vitro study, TSCs and tenocytes were stretched to 4% and 8% using a custom made mechanical loading system. Low mechanical stretching (4%) of TSCs from both patellar and Achilles tendons increased the expression of only the tenocyte-related genes (Coll. I ∼5-6 fold; tenomodulin ∼6-13 fold), but high mechanical stretching (8%) increased the expression of both tenocyte (Coll. I ∼28-50 fold; tenomodulin ∼14-48 fold) and non-tenocyte-related genes (2-5-fold){Stretching has to be high to affect the target gene}. However, in tenocytes, non-tenocyte related gene expression was not altered by the application of either low or high mechanical stretching{So mechanical stretching likely cannot induce transdifferentiation or the microenvironment is partially responsible for the upregulation of non-tendon specific genes}. Excessive mechanical loading caused anabolic changes in tendons, it also induced differentiation of TSCs into non-tenocytes.”

So we induce the differentiation of TSCs and Ligament Stem Cells(which are likely similar to tenocyte stem cells) into chondrocytes at the entheses which can then form new growth plates.

“[IGF-1’s] Eb isoform, also known as mechano-growth factor (MGF), may be a key component of the mechanism that translates mechanical loads into cellular biological changes.”

“under mechanical loading conditions, TSC population in the tendon grows, providing progenitors”

““round tenocytes” were observed in the supraspinatus tendon after intensive treadmill running (16.7 m/min) for 12 weeks. Based on our findings in this study, we suspect that these “round tenocytes” could be chondrocytes differentiated from TSCs, because i) TSCs, not tenocytes, are able to undergo non-tenocyte differentiation under high mechanical loading conditions; ii) a round shape is a typical morphology of chondrocytes, and iii) these round cells produce abundant proteoglycans detected around the cells in the tendon”

This study provides evidence for the entheses method of LSJL loading(termed henceforth as entheses LSJL).  Where the bone is clamped at the site where two bones are connected by a ligament.  These ligaments contain entheses which attach to the bone and are similar in attachment to the Zone of Ranvier.  That tendons contain stem cells which can differentiate into chondrocytes suggests that it’s probably highly similar that ligaments contain ligament stem cells which can differentiate into chondrocytes.  The difference primarily being that tendons are constantly subjected to mechanical load by virtue of their attachment to muscle.  The issue now is proving that there are stem cells within the entheses of a ligament.

4 thoughts on “Mechanical Loading on Tendons(Some evidence for Entheses LSJL)

  1. SMoKeR

    How’s it goin Tyler?!
    Sent you a message about a bone growth on my ankle at the insertion point of the Achilles Tendon.
    Hoping to get a response from you.

    Reply
  2. Vinayak Shenoy

    Okay….so how would the then produced new chondrocytes produce growth? Would the outer part of joint get bigger instead of the diaphysis ? im confused about how the new growth plate will become correctly positioned between diaphysis and upper part of long bone ?? please reply

    Reply
    1. Tyler Post author

      Well the enthesis of the ligaments is like the zone of ranvier from which the growth plate reforms if there are active stem cells. So a growth plate structure is possible to be created from such a structure.

      Reply
      1. Vinayak Shenoy

        Ok,but where would the growth plate be positioned /formed ? how will it form inside the epiphysis
        Please reply

        Reply

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